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Search for "dihydroquinoline" in Full Text gives 22 result(s) in Beilstein Journal of Organic Chemistry.
Photoredox catalysis harvesting multiple photon or electrochemical energies
- Mattia Lepori,
- Simon Schmid and
- Joshua P. Barham
Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81
Graphical Abstract
Figure 1: Oxidative and reductive activations of organic compounds harvesting photoredox catalysis.
Figure 2: General catalytic cycles of radical ion conPET (left) and radical ion e-PRC (right).
Figure 3: “Beginner’s guide”: comparison between advantages, capacities, and prospectives of conPET and PEC.
Figure 4: A) conPET reductive dehalogenation of aryl halides with PDI. B) Reductive C–H arylation with pyrrol...
Figure 5: A) Chromoselective mono- and disubstitution or polybrominated pyrimidines with pyrroles. B) Sequent...
Figure 6: A) Synthesis of pyrrolo[1,2-a]quinolines. B) Synthesis of ullazines.
Figure 7: A) Reductive phosphorylation of aryl halides via conPET. B) Selected examples from the substrate sc...
Figure 8: A) Reductive dehalogenation of aryl halides via conPET and selected examples from the substrate sco...
Figure 9: A) Reductive C–H arylation of aryl halides via conPET (top) and selected examples from the substrat...
Figure 10: A) Reductive hydrodehalogenation of aryl halides with Mes-Acr-BF4. B) Selected examples from the su...
Figure 11: A) Reductive hydrodechlorination of aryl chlorides with 4-DPAIPN. B) Proposed formation of CO2•−. C...
Figure 12: A) Reductive conPET borylation with 3CzEPAIPN (top) and selected examples from the substrate scope ...
Figure 13: Scale-up of conPET phosphorylation with 3CzEPAIPN.
Figure 14: A) Borylation of 1d. B) Characteristics and structure of PC1 with green and red parts showing the l...
Figure 15: A) Reductive C–H arylation scope with polysulfide conPET (top) and selected examples from the subst...
Figure 16: Scale-up of A) C–H arylation and B) dehaloborylation with polysulfide photocatalysis in continuous-...
Figure 17: A) Formation of [Ir1]0 and [Ir2]0 upon PET between [Ir1]+ and Et3N. B) Mechanism of multi-photon ta...
Figure 18: A) Reductive hydrodehalogenation of aryl halides via multi-photon tandem photocatalysis. B) Selecte...
Figure 19: A) Carbonylative amidation of aryl halides in continuous flow. B) Selected examples from the substr...
Figure 20: A) General scheme for reductive (RQ) and oxidative quenching (OQ) protocols using [FeIII(btz)3](PF6)...
Figure 21: A) Carbonylative amidation of alkyl iodides with [IrIII(ppy)2(dtbbpy)]PF6. B) Selected examples fro...
Figure 22: A) Carboxylative C–N bond cleavage in cyclic amines. B) Selected examples from the substrate scope....
Figure 23: A) Formal reduction of alkenes to alkanes via transfer hydrogenation. B) Selected examples from the...
Figure 24: A) Birch-type reduction of benzenes with PMP-BPI. B) Selected examples from the substrate scope (sc...
Figure 25: Proposed mechanism of the OH− mediated conPET Birch-type reduction of benzene via generation of sol...
Figure 26: Reductive detosylation of N-tosylated amides with Mes-Acr-BF4. B) Selected examples from the substr...
Figure 27: A) Reductive detosylation of N-tosyl amides by dual PRC. B) Selected examples from the substrate sc...
Figure 28: A) Mechanism of the dual PRC based on PET between [Cu(dap)2]+ and DCA. B) Mechanism of the dual PRC...
Figure 29: A) N–O bond cleavage in Weinreb amides with anthracene. B) N–O bond cleavage in Weinreb amides rely...
Figure 30: A) Pentafluorosulfanylation and fluoride elimination. B) Mechanism of the pentafluorosulfanylation ...
Figure 31: A) α-Alkoxypentafluorosulfanylation (top) and selected examples from the substrate scope (bottom). ...
Figure 32: A) Oxidative amination of arenes with azoles catalyzed by N-Ph PTZ. B) Selected examples from the s...
Figure 33: A) C(sp3)–H bond activation by HAT via chloride oxidation by *N-Ph PTZ•+. B) Proposed mechanism for...
Figure 34: A) Recycling e-PRC C–H azolation of electron-rich arenes with pyrazoles using Mes-Acr+ as a photoca...
Figure 35: A) Radical ion e-PRC direct oxidation of unactivated arenes using TAC+ as an electro-activated phot...
Figure 36: A) Radical ion e-PRC direct oxidation of unactivated arenes using TPA as an electro-activated photo...
Figure 37: Proposed mechanism (top) and mode of preassembly (bottom).
Figure 38: A) Possible preassemblies of reactive (left) vs unreactive (right) arenes. B) Calculated spin densi...
Figure 39: A) Recycling e-PRC C(sp2 )–H acetoxylation of arenes using DDQ as a photocatalyst. B) Proposed cata...
Figure 40: Gram scale hydroxylation of benzene in a recirculated flow setup.
Figure 41: A) Radical ion e-PRC vicinal diamination of alkylarenes using TAC+ as an electro-activated photocat...
Figure 42: A) Sequential oxygenation of multiple adjacent C–H bonds under radical ion e-PRC using TAC+ as an e...
Figure 43: A) Enantioselective recycling e-PRC cyanation of benzylic C–H bonds using ADQS as photocatalyst. B)...
Figure 44: Proposed tandem mechanism by Xu and co-workers.
Figure 45: A) Enantioselective recycling e-PRC decarboxylative cyanation using Cu(acac)2, Ce(OTf)3 and a box l...
Figure 46: A) Enantioselective recycling e-PRC benzylic cyanation using Cu(MeCN)4BF4, box ligand and anthraqui...
Figure 47: A) Radical ion e-PRC acetoxyhydroxylation of aryl olefins using TAC+ as an electro-activated photoc...
Figure 48: Selected examples from the substrate scope.
Figure 49: Photoelectrochemical acetoxyhydroxylation in a recirculated flow setup.
Figure 50: A) Radical ion e-PRC aminooxygenation of aryl olefins using TAC+ as an electro-activated photocatal...
Figure 51: A) Recycling e-PRC C–H alkylation of heteroarenes with organic trifluoroborates using Mes-Acr+ as p...
Figure 52: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using CeCl3·7H2O as catalyst. B) ...
Figure 53: A) Recycling e-PRC decarboxylative C–H alkylation of heteroarenes using Fe(NH4)2(SO4)2·6H2O as cata...
Figure 54: A) Recycling e-PRC C–H alkylation of heteroarenes with alkyl oxalates and 4CzIPN as photocatalyst. ...
Figure 55: A) Recycling e-PRC decarboxylative C–H carbamoylation of heteroarenes using 4CzIPN as photocatalyst...
Figure 56: A) Photoelectrochemical HAT-mediated hydrocarbon activation via the chlorine radical. B) Proposed m...
Figure 57: A) Selected examples from the substrate scope. B) Gram and decagram scale semi-continuous flow PEC ...
Figure 58: A) Photoelectrochemical HAT-mediated dehydrogenative coupling of benzothiazoles with aliphatic C–H ...
Figure 59: A) Photoelectrochemical HAT activation of ethers using electro-activated TAC+ as photocatalyst. B) ...
Figure 60: Selected examples from the substrate scope.
Figure 61: A) Photoelectrochemical HAT-mediated synthesis of alkylated benzimidazo-fused isoquinolinones using...
Figure 62: A) Decoupled photoelectrochemical cerium-catalyzed oxydichlorination of alkynes using CeCl3 as cata...
Figure 63: Proposed decoupled photoelectrochemical mechanism.
Figure 64: A) Decoupled photoelectrochemical ring-opening bromination of tertiary cycloalkanols using MgBr2 as...
Figure 65: A) Recycling e-PRC ring-opening functionalization of cycloalkanols using CeCl3 as catalyst. B) Prop...
Figure 66: Selected examples from the substrate scope of the PEC ring-opening functionalization.
Figure 67: A) Radical ion e-PRC reduction of chloro- and bromoarenes using DCA as catalyst and various accepto...
Figure 68: A) Screening of different phthalimide derivatives as catalyst for the e-PRC reduction of aryl halid...
Figure 69: Screening of different organic catalysts for the e-PRC reduction of trialkylanilium salts.
Figure 70: A) e-PRC reduction of phosphonated phenols and anilinium salts. B) Selected examples from the subst...
Figure 71: A) ConPET and e-PRC reduction of 4-bromobenzonitrile using a naphthalene diimide (NDI) precatalyst ...
Figure 72: A) Radical ion e-PRC reduction of phosphinated aliphatic alcohols with n-BuO-NpMI as catalyst. B) C...
Figure 73: Selected examples from the substrate scope.
Figure 74: A) Recycling e-PRC reductive dimerization of benzylic chlorides using a [Cu2] catalyst. B) Proposed...
Figure 75: A) Decoupled photoelectrochemical C–H alkylation of heteroarenes through deamination of Katritzky s...
Figure 76: Proposed mechanism by Chen and co-workers.
Cyclometalated iridium complexes-catalyzed acceptorless dehydrogenative coupling reaction: construction of quinoline derivatives and evaluation of their antimicrobial activities
- Hongling Shui,
- Yuhong Zhong,
- Renshi Luo,
- Zhanyi Zhang,
- Jiuzhong Huang,
- Ping Yang and
- Nianhua Luo
Beilstein J. Org. Chem. 2022, 18, 1507–1517, doi:10.3762/bjoc.18.159
- accompanied by 27% yield of 1,2-dihydroquinoline 4aa (Table 1, entry 1). Then, several other cyclometalated iridium complexes were studied. The catalysts TC-2 and TC-4 containing electron-donating ligands provided quinoline 3aa in higher chemoselectivity and yield (Table 1, entries 2 and 4). On the contrary
Graphical Abstract
Figure 1: Some new quinoline antibacterial drugs.
Figure 2: Cyclometalated iridium-catalyzed ADC reaction of o-aminobenzyl alcohols and secondary alcohols.
Figure 3: Gram-scale transformations.
Figure 4: Mechanistic investigation.
Figure 5: A speculated possible mechanism.
First series of N-alkylamino peptoid homooligomers: solution phase synthesis and conformational investigation
- Maxime Pypec,
- Laurent Jouffret,
- Claude Taillefumier and
- Olivier Roy
Beilstein J. Org. Chem. 2022, 18, 845–854, doi:10.3762/bjoc.18.85
- isolated in 78% yield after chromatography. The use of stoichiometric amounts of both partners led to incomplete conversion, with about 1/3 of the starting hydrazine being recovered after two days of reaction. We then tested 2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline (EEDQ), in dioxane, a method for in
Graphical Abstract
Figure 1: (A) Summary of the main side chains exerting significant steric and/or electronic effects and influ...
Figure 2: Solution-phase synthesis of N-(methylamino)glycine oligomers using N-Boc-N-methylhydrazine as a sub...
Scheme 1: Submonomer synthesis used for the construction of peptoids 1–5 containing N-methylamino side chains...
Scheme 2: Evaluation of the efficiency of mixed anhydride methods by coupling of 1a and 1c.
Scheme 3: (3 + 3) segment coupling of trimers 3-OH onto trimer hydrazine 3a.
Figure 3: X-ray crystal structure of peptoid dimer 2: (A) single molecule; (B) unit cell, view along b axis (...
Figure 4: NOE effect interaction observed in the 2D-NOESY spectra of monomer 1 and dimer 2 in DMSO-d6.
Figure 5: Comparison of monomers A and B with respect to their ability to form intramolecular and intermolecu...
Figure 6: Model structure of N-(NMe)glycine peptoid. (A) dimer in the repeating (pp) conformation; (B) dimer ...
Synthetic strategies toward 1,3-oxathiolane nucleoside analogues
- Umesh P. Aher,
- Dhananjai Srivastava,
- Girij P. Singh and
- Jayashree B. S
Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182
- was formylated using 2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline (EEDQ) as formylating reagent. Finally, the tert-butyldiphenylsilyl (TBDPS) group was desilylated using TBAF in THF solvent, which gave compound 99. For compound 99, the IC50 value of HIV-I cytopathogenicity in MT-4 cells was 8.0 µM
Graphical Abstract
Figure 1: Representative modified 1,3-oxathiolane nucleoside analogues.
Figure 2: Mechanism of antiviral action of 1,3-oxathiolane nucleosides, 3TC (1) and FTC (2), as chain termina...
Figure 3: Synthetic strategies for the construction of the 1,3-oxathiolane sugar ring.
Scheme 1: Synthesis of 4 from benzoyloxyacetaldehyde (3a) and 2-mercapto-substituted dimethyl acetal 3na.
Scheme 2: Synthesis of 8 from protected glycolic aldehyde 3b and 2-mercaptoacetic acid (3o).
Scheme 3: Synthesis of 20 from ᴅ-mannose (3c).
Scheme 4: Synthesis of 20 from 1,6-thioanhydro-ᴅ-galactose (3d).
Scheme 5: Synthesis of 8 from 2-(tert-butyldiphenylsilyloxy)methyl-5-oxo-1,2-oxathiolane (3m).
Scheme 6: Synthesis of 20a from ʟ-gulose derivative 3f.
Scheme 7: Synthesis of 31 from (+)-thiolactic acid 3p and 2-benzoyloxyacetaldehyde (3a).
Scheme 8: Synthesis of 35a from 1,4-dithiane-2,5-diol (3q) and glyoxylic acid (3g) hydrate.
Scheme 9: Synthetic routes toward 41 through Pummerer reaction from methyl 2-mercaptoacetate (3j) and bromoac...
Scheme 10: Strategy for the synthesis of 2,5-substituted 1,3-oxathiolane 41a using 4-nitrobenzyl glyoxylate an...
Scheme 11: Synthesis of 44 by a resolution method using Mucor miehei lipase.
Scheme 12: Synthesis of 45 from benzoyloxyacetaldehyde (3a) and 2-mercaptoacetaldehyde bis(2-methoxyethyl) ace...
Scheme 13: Synthesis of 46 from 2-mercaptoacetaldehyde bis(2-methoxyethyl) acetal (3nc) and diethyl 3-phosphon...
Scheme 14: Synthesis of 48 from 1,3-dihydroxyacetone dimer 3l.
Scheme 15: Approach toward 52 from protected alkene 3rb and lactic acid derivative 51 developed by Snead et al....
Scheme 16: Recent approach toward 56a developed by Kashinath et al.
Scheme 17: Synthesis of 56a from ʟ-menthyl glyoxylate (3h) hydrate by DKR.
Scheme 18: Possible mechanism with catalytic TEA for rapid interconversion of isomers.
Scheme 19: Synthesis of 35a by a classical resolution method through norephedrine salt 58 formation.
Scheme 20: Synthesis of 63 via [1,2]-Brook rearrangement from silyl glyoxylate 61 and thiol 3nb.
Scheme 21: Combined use of STS and CAL-B as catalysts to synthesize an enantiopure oxathiolane precursor 65.
Scheme 22: Synthesis of 1 and 1a from glycolaldehyde dimer 64 and 1,4-dithiane-2,5-diol (3q) using STS and CAL...
Scheme 23: Synthesis of 68 by using Klebsiella oxytoca.
Scheme 24: Synthesis of 71 and 72 using Trichosporon taibachii lipase and kinetic resolution.
Scheme 25: Synthesis of 1,3-oxathiolan-5-ones 77 and 78 via dynamic covalent kinetic resolution.
Figure 4: Pathway for glycosidic bond formation.
Scheme 26: First synthesis of (±)-BCH-189 (1c) by Belleau et al.
Scheme 27: Enantioselective synthesis of 3TC (1).
Scheme 28: Synthesis of cis-diastereomer 3TC (1) from oxathiolane propionate 44.
Scheme 29: Synthesis of (±)-BCH-189 (1c) via SnCl4-mediated N-glycosylation of 8.
Scheme 30: Synthesis of (+)-BCH-189 (1a) via TMSOTf-mediated N-glycosylation of 20.
Scheme 31: Synthesis of 3TC (1) from oxathiolane precursor 20a.
Scheme 32: Synthesis of 83 via N-glycosylation of 20 with pyrimidine bases.
Scheme 33: Synthesis of 85 via N-glycosylation of 20 with purine bases.
Scheme 34: Synthesis of 86 and 87 via N-glycosylation using TMSOTf and pyrimidines.
Scheme 35: Synthesis of 90 and 91 via N-glycosylation using TMSOTf and purines.
Scheme 36: Synthesis of 3TC (1) via TMSI-mediated N-glycosylation.
Scheme 37: Stereoselective N-glycosylation for the synthesis of 1 by anchimeric assistance of a chiral auxilia...
Scheme 38: Whitehead and co-workers’ approach for the synthesis of 1 via direct N-glycosylation without an act...
Scheme 39: ZrCl4-mediated stereoselective N-glycosylation.
Scheme 40: Plausible reaction mechanism for stereoselective N-glycosylation using ZrCl4.
Scheme 41: Synthesis of enantiomerically pure oxathiolane nucleosides 1 and 2.
Scheme 42: Synthesis of tetrazole analogues of 1,3-oxathiolane nucleosides 97.
Scheme 43: Synthetic approach toward 99 from 1,3-oxathiolane 45 by Camplo et al.
Scheme 44: Synthesis of 100 from oxathiolane phosphonate analogue 46.
Scheme 45: Synthetic approach toward 102 and the corresponding cyclic thianucleoside monophosphate 102a by Cha...
Scheme 46: Synthesis of emtricitabine (2) from 1,4-dithiane-2,5-diol (3q) and glyoxylic acid (3g).
Scheme 47: Synthesis of 1 and 2, respectively, from 56a–d using iodine-mediated N-glycosylation.
Scheme 48: Plausible mechanism for silane- and I2-mediated N-glycosylation.
Scheme 49: Pyridinium triflate-mediated N-glycosylation of 35a.
Scheme 50: Possible pathway for stereoselective N-glycosylation via in situ chelation with a metal ligand.
Scheme 51: Synthesis of novel 1,3-oxathiolane nucleoside 108 from oxathiolane precursor 8 and 3-benzyloxy-2-me...
Scheme 52: Synthesis of 110 using T-705 as a nucleobase and 1,3-oxathiolane derivative 8 via N-glycosylation.
Scheme 53: Synthesis of 1 using an asymmetric leaving group and N-glycosylation with bromine and mesitylene.
Scheme 54: Cytidine deaminase for enzymatic separation of 1c.
Scheme 55: Enzymatic resolution of the monophosphate derivative 116 for the synthesis of (−)-BCH-189 (1) and (...
Scheme 56: Enantioselective resolution by PLE-mediated hydrolysis to obtain FTC (2).
Scheme 57: (+)-Menthyl chloroformate as a resolving agent to separate a racemic mixture 120.
Scheme 58: Separation of racemic mixture 1c by cocrystal 123 formation with (S)-(−)-BINOL.
Advances in mercury(II)-salt-mediated cyclization reactions of unsaturated bonds
- Sumana Mandal,
- Raju D. Chaudhari and
- Goutam Biswas
Beilstein J. Org. Chem. 2021, 17, 2348–2376, doi:10.3762/bjoc.17.153
- for the synthesis of 1,4-dihydroquinoline 129 possessing a quaternary carbon center from 128 [93]. The reaction was reported via a seven-membered bicyclic hemiaminal as mentioned in the mechanism. This catalytic rearrangement protocol was successfully applied for the construction of complex carbon
- -dihydroquinoline derivatives by Hg(OTf)2 and b) plausible mechanism of formation. Synthesis of Hg(II)-salt-catalyzed heteroaromatic derivatives. Hg(II)-salt-catalyzed synthesis of dihydropyranone derivatives. Hg(II)-salt-catalyzed cyclization of alkynoic acids. Hg(II)-salt-mediated cyclization of alkyne carboxylic
Graphical Abstract
Scheme 1: Schematic representation of Hg(II)-mediated addition to an unsaturated bond.
Scheme 2: First report of Hg(II)-mediated synthesis of 2,5-dioxane derivatives from allyl alcohol.
Scheme 3: Stepwise synthesis of 2,6-distubstituted dioxane derivatives.
Scheme 4: Cyclization of carbohydrate alkene precursor.
Scheme 5: Hg(II)-mediated synthesis of C-glucopyranosyl derivatives.
Scheme 6: Synthesis of C-glycosyl amino acid derivative using Hg(TFA)2.
Scheme 7: Hg(OAc)2-mediated synthesis of α-ᴅ-ribose derivative.
Scheme 8: Synthesis of β-ᴅ-arabinose derivative 18.
Scheme 9: Hg(OAc)2-mediated synthesis of tetrahydrofuran derivatives.
Scheme 10: Synthesis of Hg(TFA)2-mediated bicyclic nucleoside derivative.
Scheme 11: Synthesis of pyrrolidine and piperidine derivatives.
Scheme 12: HgCl2-mediated synthesis of diastereomeric pyrrolidine derivatives.
Scheme 13: HgCl2-mediated cyclization of alkenyl α-aminophosphonates.
Scheme 14: Cyclization of 4-cycloocten-1-ol with Hg(OAc)2 forming fused bicyclic products.
Scheme 15: trans-Amino alcohol formation through Hg(II)-salt-mediated cyclization.
Scheme 16: Hg(OAc)2-mediated 2-aza- or 2-oxa-bicyclic ring formations.
Scheme 17: Hg(II)-salt-induced cyclic peroxide formation.
Scheme 18: Hg(OAc)2-mediated formation of 1,2,4-trioxanes.
Scheme 19: Endocyclic enol ether derivative formation through Hg(II) salts.
Scheme 20: Synthesis of optically active cyclic alanine derivatives.
Scheme 21: Hg(II)-salt-mediated formation of tetrahydropyrimidin-4(1H)-one derivatives.
Scheme 22: Cyclization of ether derivatives to form stereoselective oxazolidine derivatives.
Scheme 23: Cyclization of amide derivatives induced by Hg(OAc)2.
Scheme 24: Hg(OAc)2/Hg(TFA)2-promoted cyclization of salicylamide-derived amidal auxiliary derivatives.
Scheme 25: Hg(II)-salt-mediated cyclization to form dihydrobenzopyrans.
Scheme 26: HgCl2-induced cyclization of acetylenic silyl enol ether derivatives.
Scheme 27: Synthesis of exocyclic and endocyclic enol ether derivatives.
Scheme 28: Cyclization of trans-acetylenic alcohol by treatment with HgCl2.
Scheme 29: Synthesis of benzofuran derivatives in presence of HgCl2.
Scheme 30: a) Hg(II)-salt-mediated cyclization of 4-hydroxy-2-alkyn-1-ones to furan derivatives and b) its mec...
Scheme 31: Cyclization of arylacetylenes to synthesize carbocyclic and heterocyclic derivatives.
Scheme 32: Hg(II)-salt-promoted cyclization–rearrangement to form heterocyclic compounds.
Scheme 33: a) HgCl2-mediated cyclization reaction of tethered alkyne dithioacetals; and b) proposed mechanism.
Scheme 34: Cyclization of aryl allenic ethers on treatment with Hg(OTf)2.
Scheme 35: Hg(TFA)2-mediated cyclization of allene.
Scheme 36: Hg(II)-catalyzed intramolecular trans-etherification reaction of 2-hydroxy-1-(γ-methoxyallyl)tetrah...
Scheme 37: a) Cyclization of alkene derivatives by catalytic Hg(OTf)2 salts and b) mechanism of cyclization.
Scheme 38: a) Synthesis of 1,4-dihydroquinoline derivatives by Hg(OTf)2 and b) plausible mechanism of formatio...
Scheme 39: Synthesis of Hg(II)-salt-catalyzed heteroaromatic derivatives.
Scheme 40: Hg(II)-salt-catalyzed synthesis of dihydropyranone derivatives.
Scheme 41: Hg(II)-salt-catalyzed cyclization of alkynoic acids.
Scheme 42: Hg(II)-salt-mediated cyclization of alkyne carboxylic acids and alcohol to furan, pyran, and spiroc...
Scheme 43: Hg(II)-salt-mediated cyclization of 1,4-dihydroxy-5-alkyne derivatives.
Scheme 44: Six-membered morpholine derivative formation by catalytic Hg(II)-salt-induced cyclization.
Scheme 45: Hg(OTf)2-catalyzed hydroxylative carbocyclization of 1,6-enyne.
Scheme 46: a) Hg(OTf)2-catalyzed hydroxylative carbocyclization of 1,6-enyne. b) Proposed mechanism.
Scheme 47: a) Synthesis of carbocyclic derivatives using a catalytic amount of Hg(II) salt. b) Proposed mechan...
Scheme 48: Cyclization of 1-alkyn-5-ones to 2-methylfuran derivatives.
Scheme 49: Hg(NO3)2-catalyzed synthesis of 2-methylenepiperidine.
Scheme 50: a) Preparation of indole derivatives through cycloisomerization of 2-ethynylaniline and b) its mech...
Scheme 51: a) Hg(OTf)2-catalyzed synthesis of 3-indolinones and 3-coumaranones and b) simplified mechanism.
Scheme 52: a) Hg(OTf)2-catalyzed one pot cyclization of nitroalkyne and b) its plausible mechanism.
Scheme 53: Synthesis of tricyclic heterocyclic scaffolds.
Scheme 54: HgCl2-mediated cyclization of 2-alkynylphenyl alkyl sulfoxide.
Scheme 55: a) Hg(OTf)2-catalyzed cyclization of allenes and alkynes. b) Proposed mechanism of cyclization.
Scheme 56: Stereoselective synthesis of tetrahydropyran derivatives.
Scheme 57: a) Hg(ClO4)2-catalyzed cyclization of α-allenol derivatives. b) Simplified mechanism.
Scheme 58: Hg(TFA)2-promoted cyclization of a γ-hydroxy alkene derivative.
Scheme 59: Synthesis Hg(II)-salt-mediated cyclization of allyl alcohol for the construction of ventiloquinone ...
Scheme 60: Hg(OAc)2-mediated cyclization as a key step for the synthesis of hongconin.
Scheme 61: Examples of Hg(II)-salt-mediated cyclized ring formation in the syntheses of (±)-fastigilin C and (...
Scheme 62: Formal synthesis of (±)-thallusin.
Scheme 63: Total synthesis of hippuristanol and its analog.
Scheme 64: Total synthesis of solanoeclepin A.
Scheme 65: a) Synthesis of Hg(OTf)2-catalyzed azaspiro structure for the formation of natural products. b) Pro...
Microwave-assisted multicomponent reactions in heterocyclic chemistry and mechanistic aspects
- Shivani Gulati,
- Stephy Elza John and
- Nagula Shankaraiah
Beilstein J. Org. Chem. 2021, 17, 819–865, doi:10.3762/bjoc.17.71
Graphical Abstract
Figure 1: Marketed drugs with acridine moiety.
Scheme 1: Synthesis of 4-arylacridinediones.
Scheme 2: Proposed mechanism for acridinedione synthesis.
Scheme 3: Synthesis of tetrahydrodibenzoacridinones.
Scheme 4: Synthesis of naphthoacridines.
Scheme 5: Plausible mechanism for naphthoacridines.
Figure 2: Benzoazepines based potent molecules.
Scheme 6: Synthesis of azepinone.
Scheme 7: Proposed mechanism for azepinone formation.
Scheme 8: Synthesis of benzoazulenen-1-one derivatives.
Scheme 9: Proposed mechanism for benzoazulene-1-one synthesis.
Figure 3: Indole-containing pharmacologically active molecules.
Scheme 10: Synthesis of functionalized indoles.
Scheme 11: Plausible mechanism for the synthesis of functionalized indoles.
Scheme 12: Synthesis of spirooxindoles.
Scheme 13: Synthesis of substituted spirooxindoles.
Scheme 14: Plausible mechanism for the synthesis of substituted spirooxindoles.
Scheme 15: Synthesis of pyrrolidinyl spirooxindoles.
Scheme 16: Proposed mechanism for pyrrolidinyl spirooxindoles.
Figure 4: Pyran-containing biologically active molecules.
Scheme 17: Synthesis of functionalized benzopyrans.
Scheme 18: Plausible mechanism for synthesis of benzopyran.
Scheme 19: Synthesis of indoline-spiro-fused pyran derivatives.
Scheme 20: Proposed mechanism for indoline-spiro-fused pyran.
Scheme 21: Synthesis of substituted naphthopyrans.
Figure 5: Marketed drugs with pyrrole ring.
Scheme 22: Synthesis of tetra-substituted pyrroles.
Scheme 23: Mechanism for silica-supported PPA-SiO2-catalyzed pyrrole synthesis.
Scheme 24: Synthesis of pyrrolo[1,10]-phenanthrolines.
Scheme 25: Proposed mechanism for pyrrolo[1,10]-phenanthrolines.
Figure 6: Marketed drugs and molecules containing pyrimidine and pyrimidinones skeletons.
Scheme 26: MWA-MCR pyrimidinone synthesis.
Scheme 27: Two proposed mechanisms for pyrimidinone synthesis.
Scheme 28: MWA multicomponent synthesis of dihydropyrimidinones.
Scheme 29: Proposed mechanism for dihydropyrimidinones.
Figure 7: Biologically active fused pyrimidines.
Scheme 30: MWA- MCR for the synthesis of pyrrolo[2,3-d]pyrimidines.
Scheme 31: Proposed mechanism for pyrrolo[2,3-d]pyrimidines.
Scheme 32: Synthesis of substituted pyrrolo[2,3-d]pyrimidine-2,4-diones.
Scheme 33: Probable pathway for pyrrolo[2,3-d]pyrimidine-2,4-diones.
Scheme 34: Synthesis of pyridopyrimidines.
Scheme 35: Plausible mechanism for the synthesis of pyridopyrimidines.
Scheme 36: Synthesis of dihydropyridopyrimidine and dihydropyrazolopyridine.
Scheme 37: Proposed mechanism for the formation of dihydropyridopyrimidine.
Scheme 38: Synthesis of thiopyrano[4,3-d]pyrimidines.
Scheme 39: Plausible mechanism for the synthesis of thiopyrano[4,3-d]pyrimidines.
Scheme 40: Synthesis of decorated imidazopyrimidines.
Scheme 41: Proposed mechanism for imidazopyrimidine synthesis.
Figure 8: Pharmacologically active molecules containing purine bases.
Scheme 42: Synthesis of aza-adenines.
Scheme 43: Synthesis of 5-aza-7-deazapurines.
Scheme 44: Proposed mechanism for deazapurines synthesis.
Figure 9: Biologically active molecules containing pyridine moiety.
Scheme 45: Synthesis of steroidal pyridines.
Scheme 46: Proposed mechanism for steroidal pyridine.
Scheme 47: Synthesis of N-alkylated 2-pyridones.
Scheme 48: Two possible mechanisms for pyridone synthesis.
Scheme 49: Synthesis of pyridone derivatives.
Scheme 50: Postulated mechanism for synthesis of pyridone.
Figure 10: Biologically active fused pyridines.
Scheme 51: Benzimidazole-imidazo[1,2-a]pyridines synthesis.
Scheme 52: Mechanism for the synthesis of benzimidazole-imidazo[1,2-a]pyridines.
Scheme 53: Synthesis of pyrazolo[3,4-b]pyridine-5-spirocycloalkanedione derivatives.
Scheme 54: Proposed mechanism for spiro-pyridines.
Scheme 55: Functionalized macrocyclane-fused pyrazolo[3,4-b]pyridine derivatives.
Scheme 56: Mechanism postulated for macrocyclane-fused pyrazolo[3,4-b]pyridine.
Scheme 57: Generation of pyrazolo[3,4-b]pyridines.
Scheme 58: Proposed mechanism for the synthesis of pyrazolo[3,4-b]pyridines.
Scheme 59: Proposed mechanism for the synthesis of azepinoindole.
Figure 11: Pharmaceutically important molecules with quinoline moiety.
Scheme 60: Povarov-mediated quinoline synthesis.
Scheme 61: Proposed mechanism for Povarov reaction.
Scheme 62: Synthesis of pyrazoloquinoline.
Scheme 63: Plausible mechanism for pyrazoloquinoline synthesis.
Figure 12: Quinazolinones as pharmacologically significant scaffolds.
Scheme 64: Four-component reaction for dihydroquinazolinone.
Scheme 65: Proposed mechanism for dihydroquinazolinones.
Scheme 66: Synthesis purine quinazolinone and PI3K-δ inhibitor.
Scheme 67: Synthesis of fused benzothiazolo/benzoimidazoloquinazolinones.
Scheme 68: Proposed mechanism for fused benzothiazolo/benzoimidazoloquinazolinones.
Scheme 69: On-water reaction for synthesis of thiazoloquinazolinone.
Scheme 70: Proposed mechanism for the thiazoloquinazolinone synthesis.
Scheme 71: β-Cyclodextrin-mediated synthesis of indoloquinazolinediones.
Scheme 72: Proposed mechanism for synthesis of indoloquinazolinediones.
Figure 13: Triazoles-containing marketted drugs and pharmacologically active molecules.
Scheme 73: Cu(I) DAPTA-catalyzed 1,2,3-triazole formation.
Scheme 74: Mechanism for Cu(I) DAPTA-catalyzed triazole formation.
Scheme 75: Synthesis of β-hydroxy-1,2,3-triazole.
Scheme 76: Proposed mechanism for synthesis of β-hydroxy-1,2,3-triazoles.
Scheme 77: Synthesis of bis-1,2,4-triazoles.
Scheme 78: Proposed mechanism for bis-1,2,4-triazoles synthesis.
Figure 14: Thiazole containing drugs.
Scheme 79: Synthesis of a substituted thiazole ring.
Scheme 80: Synthesis of pyrazolothiazoles.
Figure 15: Chromene containing drugs.
Scheme 81: Magnetic nanocatalyst-mediated aminochromene synthesis.
Scheme 82: Proposed mechanism for the synthesis of chromenes.
Total synthesis of pyrrolo[2,3-c]quinoline alkaloid: trigonoine B
- Takashi Nishiyama,
- Erina Hamada,
- Daishi Ishii,
- Yuuto Kihara,
- Nanase Choshi,
- Natsumi Nakanishi,
- Mari Murakami,
- Kimiko Taninaka,
- Noriyuki Hatae and
- Tominari Choshi
Beilstein J. Org. Chem. 2021, 17, 730–736, doi:10.3762/bjoc.17.62
- triflate 7, and the total syntheses of marinoquinolines 3a, 3b, and 3e were accomplished by introducing different substituents at the C4 position. However, despite our efforts to introduce dihydroquinoline derivatives into triflate 7 using various conditions, the synthesis of 8 could not be achieved
- by electrocyclization of 2-(pyrrol-3-yl)benzene containing a carbodiimide moiety as a 2-azahexatriene system. Results and Discussion Scheme 2 illustrates the retrosynthetic strategy designed to synthesize triogonoine B (1). It was speculated that the dihydroquinoline moiety of trigonoine B (1) could
Graphical Abstract
Figure 1: Natural products possessing the pyrrolo[2,3-c]quinoline skeleton.
Scheme 1: Total synthesis of marinoquinolines and the failure of the introduction of a tetrahydroquinoline mo...
Scheme 2: Retrosynthetic analysis of the pyrrolo[2,3-c]quinoline ring construction.
Scheme 3: Synthesis of N-substituted 4-aminopyrrolo[3,2-c]quinoline 18.
Scheme 4: Synthesis of the tetrahydroquinoline moiety through cycloamination.
Scheme 5: Synthesis of trigonoine B (1).
Study on the regioselectivity of the N-ethylation reaction of N-benzyl-4-oxo-1,4-dihydroquinoline-3-carboxamide
- Pedro N. Batalha,
- Luana da S. M. Forezi,
- Maria Clara R. Freitas,
- Nathalia M. de C. Tolentino,
- Ednilsom Orestes,
- José Walkimar de M. Carneiro,
- Fernanda da C. S. Boechat and
- Maria Cecília B. V. de Souza
Beilstein J. Org. Chem. 2019, 15, 388–400, doi:10.3762/bjoc.15.35
- antibacterial and antiviral. The presence of a carboxamide unit connected to carbon C-3 of the 4-oxoquinoline core has been associated with various biological activities. Experimentally, the N-ethylation reaction of N-benzyl-4-oxo-1,4-dihydroquinoline-3-carboxamide occurs at the nitrogen of the oxoquinoline
- group, in a regiosselective way. In this work, we employed DFT methods to investigate the regiosselective ethylation reaction of N-benzyl-4-oxo-1,4-dihydroquinoline-3-carboxamide, evaluating its acid/base behavior and possible reaction paths. Keywords: alkylation; carboxamide; oxoquinoline; quinolone
- mentioned above, we have been putting some effort on synthesizing different 4-oxoquinoline-3-carboxamide derivatives as potential anticancer agents [13]. The synthesis of such derivatives have been planned considering that, once having obtained the 4-oxo-1,4-dihydroquinoline-3-carboxamide scaffold
Graphical Abstract
Figure 1: Structures of some bioactive 4-oxoquinoline-3-carboxamide derivatives 1–4 with different bioactive ...
Figure 2: Structural modifications on the 4-oxo-1,4-dihydroquinoline-3-carboxamide scaffold.
Scheme 1: Synthetic route for the preparation of 1-ethyl-4-oxoquinoline-3-carboxamide 7.
Scheme 2: Reaction steps and main transition state leading to compound 7.
Figure 3: Same scale partial 1H NMR spectra of compounds 5 and 7 (DMSO-d6, 500 MHz).
Figure 4: 1H,1H-COSY spectrum of derivative 7 (DMSO-d6, 500 MHz).
Figure 5: Partial HMBC spectrum of derivative 7 (DMSO-d6, 500 MHz).
Figure 6: Asymmetric unit of product 7.
Scheme 3: Deprotonation of 5 forming 8a and 8b, followed by reaction with bromoethane leading to products 7 a...
Scheme 4: Acid–base equilibria considered for the data displayed in Table 2.
Scheme 5: Charge dispersion due to resonance effects for both deprotonated species.
Transition-metal-free [3 + 3] annulation of indol-2-ylmethyl carbanions to nitroarenes. A novel synthesis of indolo[3,2-b]quinolines (quindolines)
- Michał Nowacki and
- Krzysztof Wojciechowski
Beilstein J. Org. Chem. 2018, 14, 194–202, doi:10.3762/bjoc.14.14
- to azaxylylene E that electrocyclizes to the dihydroquinoline framework F from which, after elimination of another molecule of silanol, the final product is formed. Similar electrocyclizations of aza-ortho-xylylenes leading to condensed heterocycles are known processes [30][31]. Conclusion We
Graphical Abstract
Figure 1: Selected indolo[3,2-b]quinolines (quindolines) with biological activity.
Scheme 1: Selected starting materials for the construction of the quindoline system.
Scheme 2: Synthesis of condensed pyridines mediated by a σH-adduct.
Scheme 3: Formation of condensed isoxazole derivatives.
Scheme 4: Reaction of unprotected indole ester 1c with 4-chloronitrobenzene.
Scheme 5: A plausible mechanism for the formation of 11-(phenylsulfonyl)indolo[3,2-b]quinolines.
Progress in copper-catalyzed trifluoromethylation
- Guan-bao Li,
- Chao Zhang,
- Chun Song and
- Yu-dao Ma
Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11
- tetrahydroisoquinoline with DDQ generates dihydroquinoline salt A. Next, CuCF3, generated by the reaction of CuI and CF3TMS/KF, undergoes a nucleophilic addition with A affording the desired products and the copper salt. The generated copper salt would be reused to form CuCF3 in the nucleophilic step again. So, only a
Graphical Abstract
Figure 1: Selected examples of pharmaceutical and agrochemical compounds containing the trifluoromethyl group....
Scheme 1: Introduction of a diamine into copper-catalyzed trifluoromethylation of aryl iodides.
Scheme 2: Addition of a Lewis acid into copper-catalyzed trifluoromethylation of aryl iodides and the propose...
Scheme 3: Trifluoromethylation of heteroaromatic compounds using S-(trifluoromethyl)diphenylsulfonium salts a...
Scheme 4: The preparation of a new trifluoromethylation reagent and its application in trifluoromethylation o...
Scheme 5: Trifluoromethylation of aryl iodides using CF3CO2Na as a trifluoromethyl source.
Scheme 6: Trifluoromethylation of aryl iodides using MTFA as a trifluoromethyl source.
Scheme 7: Trifluoromethylation of aryl iodides using CF3CO2K as a trifluoromethyl source.
Scheme 8: Trifluoromethylation of aryl iodides and heteroaryl bromides using [Cu(phen)(O2CCF3)] as a trifluor...
Scheme 9: Trifluoromethylation of aryl iodides with DFPB and the proposed mechanism.
Scheme 10: Trifluoromethylation of aryl iodides using TCDA as a trifluoromethyl source. Reaction conditions: [...
Scheme 11: The mechanism of trifluoromethylation using Cu(II)(O2CCF2SO2F)2 as a trifluoromethyl source.
Scheme 12: Trifluoromethylation of benzyl bromide reported by Shibata’s group.
Scheme 13: Trifluoromethylation of allylic halides and propargylic halides reported by the group of Nishibayas...
Scheme 14: Trifluoromethylation of propargylic halides reported by the group of Nishibayashi.
Scheme 15: Trifluoromethylation of alkyl halides reported by Nishibayashi’s group.
Scheme 16: Trifluoromethylation of pinacol esters reported by the group of Gooßen.
Scheme 17: Trifluoromethylation of primary and secondary alkylboronic acids reported by the group of Fu.
Scheme 18: Trifluoromethylation of boronic acid derivatives reported by the group of Liu.
Scheme 19: Trifluoromethylation of organotrifluoroborates reported by the group of Huang.
Scheme 20: Trifluoromethylation of aryl- and vinylboronic acids reported by the group of Shibata.
Scheme 21: Trifluoromethylation of arylboronic acids via the merger of photoredox and Cu catalysis.
Scheme 22: Trifluoromethylation of arylboronic acids reported by Sanford’s group. Isolated yield. aYields dete...
Scheme 23: Trifluoromethylation of arylboronic acids and vinylboronic acids reported by the group of Beller. Y...
Scheme 24: Copper-mediated Sandmeyer type trifluoromethylation using Umemoto’s reagent as a trifluoromethylati...
Scheme 25: Copper-mediated Sandmeyer type trifluoromethylation using TMSCF3 as a trifluoromethylation reagent ...
Scheme 26: One-pot Sandmeyer trifluoromethylation reported by the group of Gooßen.
Scheme 27: Copper-catalyzed trifluoromethylation of arenediazonium salts in aqueous media.
Scheme 28: Copper-mediated Sandmeyer trifluoromethylation using Langlois’ reagent as a trifluoromethyl source ...
Scheme 29: Trifluoromethylation of terminal alkenes reported by the group of Liu.
Scheme 30: Trifluoromethylation of terminal alkenes reported by the group of Wang.
Scheme 31: Trifluoromethylation of tetrahydroisoquinoline derivatives reported by Li and the proposed mechanis...
Scheme 32: Trifluoromethylation of phenol derivatives reported by the group of Hamashima.
Scheme 33: Trifluoromethylation of hydrazones reported by the group of Baudoin and the proposed mechanism.
Scheme 34: Trifluoromethylation of benzamides reported by the group of Tan.
Scheme 35: Trifluoromethylation of heteroarenes and electron-deficient arenes reported by the group of Qing an...
Scheme 36: Trifluoromethylation of N-aryl acrylamides using CF3SO2Na as a trifluoromethyl source.
Scheme 37: Trifluoromethylation of aryl(heteroaryl)enol acetates using CF3SO2Na as the source of CF3 and the p...
Scheme 38: Trifluoromethylation of imidazoheterocycles using CF3SO2Na as a trifluoromethyl source and the prop...
Scheme 39: Copper-mediated trifluoromethylation of terminal alkynes using TMSCF3 as a trifluoromethyl source a...
Scheme 40: Improved copper-mediated trifluoromethylation of terminal alkynes reported by the group of Qing.
Scheme 41: Copper-catalyzed trifluoromethylation of terminal alkynes reported by the group of Qing.
Scheme 42: Copper-catalyzed trifluoromethylation of terminal alkynes using Togni’s reagent and the proposed me...
Scheme 43: Copper-catalyzed trifluoromethylation of terminal alkynes using Umemoto’s reagent reported by the g...
Scheme 44: Copper-catalyzed trifluoromethylation of 3-arylprop-1-ynes reported by Xiao and Lin and the propose...
Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis
- Anna Kuźnik,
- Roman Mazurkiewicz and
- Beata Fryczkowska
Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269
- -(1,2-dihydroquinoline-2-ylidene)pyruvate (91), Yavari and co-workers obtained 4-(2-quinolyl)cyclobutene-1,2,3-tricarboxylic acid triesters 94 and isomeric cyclopentenone derivatives 95 with total yields of 87–94% and a ratio of 1:4 via the intramolecular Wittig reaction. The addition of
- expected ylide 97. The subsequent intramolecular Wittig reaction in boiling toluene gave the 1,2-dihydroquinoline derivatives 98, which underwent dehydrogenation into the corresponding 4-arylquinolines 99 in yields of 55–90% (Scheme 57) [70]. In an analogous manner, Yavari and Mosslemin synthesized furan
Graphical Abstract
Scheme 1: Generation of phosphorus ylides from vinylphosphonium salts.
Scheme 2: Intramolecular Wittig reaction with the use of vinylphosphonium salts.
Scheme 3: Alkylation of diphenylvinylphosphine with methyl or benzyl iodide.
Scheme 4: Methylation of isopropenyldiphenylphosphine with methyl iodide.
Scheme 5: Alkylation of phosphines with allyl halide derivatives and subsequent isomerization of intermediate...
Scheme 6: Alkylation of triphenylphosphine with vinyl triflates in the presence of (Ph3P)4Pd.
Scheme 7: Mechanism of alkylation of triphenylphosphine with vinyl triflates in the presence of (Ph3P)4Pd as ...
Scheme 8: β-Elimination of phenol from β-phenoxyethyltriphenylphosphonium bromide.
Scheme 9: β-Elimination of phenol from β-phenoxyethylphosphonium salts in an alkaline environment.
Scheme 10: Synthesis and subsequent dehydrohalogenation of α-bromoethylphosphonium bromide.
Scheme 11: Synthesis of tributylvinylphosphonium iodides via Peterson-type olefination of α-trimethylsilylphos...
Scheme 12: Synthesis of 1-cycloalkenetriphenylphosphonium salts by electrochemical oxidation of triphenylphosp...
Scheme 13: Suggested mechanism for the electrochemical synthesis of 1-cycloalkenetriphenylphosphonium salts.
Scheme 14: Generation of α,β-(dialkoxycarbonyl)vinylphosphonium salts by addition of triphenylphosphine to ace...
Scheme 15: Synthesis of 2-(N-acylamino)vinylphosphonium halides by imidoylation of β-carbonyl ylides with imid...
Scheme 16: Imidoylation of β-carbonyl ylides with imidoyl halides generated in situ.
Scheme 17: Synthesis of 2-benzoyloxyvinylphosphonium bromide from 2-propynyltriphenylphosphonium bromide.
Scheme 18: Synthesis of 2-aminovinylphosphonium salts via nucleophilic addition of amines to 2-propynyltriphen...
Scheme 19: Deacylation of 2-(N-acylamino)vinylphosphonium chlorides to 2-aminovinylphosphonium salts.
Scheme 20: Resonance structures of 2-aminovinylphosphonium salts and tautomeric equilibrium between aminovinyl...
Scheme 21: Synthesis of 2-aminovinylphosphonium salts by reaction of (formylmethyl)triphenylphosphonium chlori...
Scheme 22: Generation of ylides by reaction of vinyltriphenylphosphonium bromide with nucleophiles and their s...
Scheme 23: Intermolecular Wittig reaction with the use of vinylphosphonium bromide and organocopper compounds ...
Scheme 24: Intermolecular Wittig reaction with the use of ylides generated from vinylphosphonium bromides and ...
Scheme 25: Direct transformation of vinylphosphonium salts into ylides in the presence of potassium tert-butox...
Scheme 26: A general method for synthesis of carbo- and heterocyclic systems by the intramolecular Wittig reac...
Scheme 27: Synthesis of 2H-chromene by reaction of vinyltriphenylphosphonium bromide with sodium 2-formylpheno...
Scheme 28: Synthesis of 2,5-dihydro-2,3-dimethylfuran by reaction of vinylphosphonium bromide with 3-hydroxy-2...
Scheme 29: Synthesis of 2H-chromene and 2,5-dihydrofuran derivatives in the intramolecular Wittig reaction wit...
Scheme 30: Enantioselective synthesis of 3,6-dihydropyran derivatives from vinylphosphonium bromide and enanti...
Scheme 31: Synthesis of 2,5-dihydrothiophene derivatives in the intramolecular Wittig reaction from vinylphosp...
Scheme 32: Synthesis of bicyclic pyrrole derivatives in the reaction of vinylphosphonium halides and 2-pyrrolo...
Scheme 33: Stereoselective synthesis of bicyclic 2-pyrrolidinone derivatives in the reaction of vinylphosphoni...
Scheme 34: Stereoselective synthesis of 3-pyrroline derivatives in the intramolecular Wittig reaction from vin...
Scheme 35: Synthesis of cyclic alkenes in the intramolecular Wittig reaction from vinylphosphonium bromide and...
Scheme 36: Synthesis of 1,3-cyclohexadienes by reaction of 1,3-butadienyltriphenylphosphonium bromide with eno...
Scheme 37: Synthesis of bicyclo[3.3.0]octenes by reaction of vinylphosphonium salts with cyclic diketoester.
Scheme 38: Synthesis of quinoline derivatives in the intramolecular Wittig reaction from 2-(2-acylphenylamino)...
Scheme 39: Stereoselective synthesis of γ-aminobutyric acid in the intermolecular Wittig reaction from chiral ...
Scheme 40: Synthesis of allylamines in the intermolecular Wittig reaction from 2-aminovinylphosphonium bromide...
Scheme 41: A general route towards α,β-di(alkoxycarbonyl)vinylphosphonium salts and their subsequent possible ...
Scheme 42: Generation of resonance-stabilized phosphorus ylides via the reaction of triphenylphosphine with di...
Scheme 43: Synthesis of resonance-stabilized phosphorus ylides in the reaction of triphenylphosphine, dialkyl ...
Scheme 44: Synthesis of resonance-stabilized phosphorus ylides via the reaction of triphenylphosphine with dia...
Scheme 45: Generation of resonance-stabilized phosphorus ylides in the reaction of acetylenedicarboxylate, tri...
Scheme 46: Synthesis of resonance-stabilized phosphorus ylides via the reaction of dialkyl acetylenedicarboxyl...
Scheme 47: Synthesis of resonance-stabilized ylides derived from semicarbazones, aromatic amides, and 3-(aryls...
Scheme 48: Synthesis of resonance-stabilized ylides via the reaction of triphenylphosphine with dialkyl acetyl...
Scheme 49: Synthesis of resonance-stabilized ylides in the reaction of triphenylphosphine, dialkyl acetylenedi...
Scheme 50: Synthesis of N-acylated α,β-unsaturated γ-lactams via resonance-stabilized phosphorus ylides derive...
Scheme 51: Synthesis of resonance-stabilized phosphorus ylides derived from 6-amino-N,N'-dimethyluracil and th...
Scheme 52: Generation of resonance-stabilized phosphorus ylides in the reaction of triphenylphosphine, dialkyl...
Scheme 53: Synthesis of resonance-stabilized phosphorus ylides via the reaction of triphenylphosphine with dia...
Scheme 54: Synthesis of 1,3-dienes via intramolecular Wittig reaction with the use of resonance-stabilized yli...
Scheme 55: Synthesis of 1,3-dienes in the intramolecular Wittig reaction from ylides generated from dimethyl a...
Scheme 56: Synthesis of 4-(2-quinolyl)cyclobutene-1,2,3-tricarboxylic acid triesters and isomeric cyclopenteno...
Scheme 57: Synthesis of 4-arylquinolines via resonance-stabilized ylides in the intramolecular Wittig reaction....
Scheme 58: Synthesis of furan derivatives via resonance-stabilized ylides in the intramolecular Wittig reactio...
Scheme 59: Synthesis of 1,3-indanedione derivatives via resonance-stabilized ylides in the intermolecular Witt...
Scheme 60: Synthesis of coumarin derivatives via nucleophilic displacement of the triphenylphosphonium group i...
Scheme 61: Synthesis of 6-formylcoumarin derivatives and their application in the synthesis of dyads.
Scheme 62: Synthesis of di- and tricyclic coumarin derivatives in the reaction of pyrocatechol with two vinylp...
Scheme 63: Synthesis of mono-, di-, and tricyclic derivatives in the reaction of pyrogallol with one or two vi...
Scheme 64: Synthesis of 1,4-benzoxazine derivative by nucleophilic displacement of the triphenylphosphonium gr...
Scheme 65: Synthesis of 7-oxo-7H-pyrido[1,2,3-cd]perimidine derivative via nucleophilic displacement of the tr...
Scheme 66: Application of vinylphosphonium salts in the Diels–Alder reaction with dienes.
Scheme 67: Synthesis of pyrroline derivatives from vinylphosphonium bromide and 5-(4H)-oxazolones.
Scheme 68: Synthesis of pyrrole derivatives in the reactions of vinyltriphenylphosphonium bromide with protona...
Scheme 69: Synthesis of dialkyl 2-(alkylamino)-5-aryl-3,4-furanedicarboxylates via intermediate α,β-di(alkoxyc...
Scheme 70: Synthesis of 1,4-benzoxazine derivatives from acetylenedicarboxylates, phosphines, and 1-nitroso-2-...
Practical synthetic strategies towards lipophilic 6-iodotetrahydroquinolines and -dihydroquinolines
- David R. Chisholm,
- Garr-Layy Zhou,
- Ehmke Pohl,
- Roy Valentine and
- Andrew Whiting
Beilstein J. Org. Chem. 2016, 12, 1851–1862, doi:10.3762/bjoc.12.174
- temperatures. Coupling these strongly electron-donating scaffolds to electron-accepting moieties caused the resulting structures to exhibit strong fluorescence. Keywords: cyclisation; dihydroquinoline; elimination; reduction; tetrahydroquinoline; Introduction Tetrahydroquinolines (THQ) and dihydroquinolines
- (ca. 5%) of 1,4-DHQ 22 in addition to 21. Ab initio simulation of 22 (Figure 2) indicated that the enamine functionality causes a flattening of the dihydroquinoline ring to give a more planar, quinoline-like structure. We were intrigued by the result of these stereoelectronic and conformational
- in the literature. Iodoquinolin-2-ones 13, 19 and 20a, are stable intermediates, and we have developed straightforward, practical and scalable procedures towards their synthesis. We have also demonstrated the novel synthesis of dihydroquinoline 22, by what appears to be a collapse of the intermediate
Graphical Abstract
Figure 1: Tetrahydroquinoline (THQ) and dihydroquinoline (DHQ) scaffolds to be synthesised.
Scheme 1: Proposed retrosynthesis scheme to access N-isopropyl-THQ 2.
Scheme 2: Synthesis of THQ 3 by initial N-alkylations, followed by PPA-mediated cyclisation.
Scheme 3: Bromination of 3 and attempted halogen exchange of the intermediate 7.
Scheme 4: Synthesis of THQ 10, by initial aza-Michael addition, followed by formation of the tertiary alcohol ...
Scheme 5: Synthesis of THQ 14 by initial acylation, cyclisation with H2SO4 and reduction with borane·dimethyl...
Scheme 6: N-Alkylation of 13 and 14.
Scheme 7: Facile route for the synthesis of 20a.
Scheme 8: Synthesis of THQ 21 and DHQ 22 using borane·dimethyl sulphide complex or DIBAL, respectively.
Figure 2: Simulated structure of 22 indicates a flattened quinoline-like structure. Hartree–Fock calculations...
Scheme 9: Postulated mechanism for the formation of 22 using DIBAL.
Figure 3: Combined, normalised absorption and emission spectra of 28 in chloroform. Absorption spectrum was r...
Scheme 10: Miyaura borylation of 21 and 22 to give crystalline boronic esters 29 and 30.
Figure 4: Comparison of the crystal structures of 29 (left) and 30 (right) as viewed along the plane of the a...
Figure 5: Combined, normalised absorption and emission spectra of 30 in diethyl ether. Absorption spectrum wa...
Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates
- Mohammad Haji
Beilstein J. Org. Chem. 2016, 12, 1269–1301, doi:10.3762/bjoc.12.121
- ) [88]. Further, 1-acyl-1,2-dihydroquinoline-2-phosphonates 251 and 2-acyl-1,2-dihydroisoquinoline-1-phosphonates 252 have been prepared via the one-pot reaction of quinoline (242) or isoquinolines 249 with acyl chlorides 250 and trimethyl phosphite in the presence of NaI in 22–94% yields depending on
- via the [3 + 2] cycloaddition of phosphonate azomethine ylides with ynones. Three-component synthesis of 1H-pyrrol-2-ylphosphonates. The classical Reissert reaction. One-pot three-component synthesis of N-phosphorylated isoquinolines. One-pot three-component synthesis of 1-acyl-1,2-dihydroquinoline-2
Graphical Abstract
Scheme 1: The Biginelli condensation.
Scheme 2: The Biginelli reaction of β-ketophosphonates catalyzed by ytterbium triflate.
Scheme 3: Trimethylchlorosilane-mediated Biginelli reaction of diethyl (3,3,3-trifluoropropyl-2-oxo)phosphona...
Scheme 4: Biginelli reaction of dialkyl (3,3,3-trifluoropropyl-2-oxo)phosphonate with trialkyl orthoformates ...
Scheme 5: p-Toluenesulfonic acid-promoted Biginelli reaction of β-ketophosphonates, aryl aldehydes and urea.
Scheme 6: General Kabachnik–Fields reaction for the synthesis of α-aminophosphonates.
Scheme 7: Phthalocyanine–AlCl catalyzed Kabachnik–Fields reaction of N-Boc-piperidin-4-one with diethyl phosp...
Scheme 8: Kabachnik–Fields reaction of isatin with diethyl phosphite and benzylamine.
Scheme 9: Magnetic Fe3O4 nanoparticle-supported phosphotungstic acid-catalyzed Kabachnik–Fields reaction of i...
Scheme 10: The Mg(ClO4)2-catalyzed Kabachnik–Fields reaction of 1-tosylpiperidine-4-one.
Scheme 11: An asymmetric version of the Kabachnik–Fields reaction for the synthesis of α-amino-3-piperidinylph...
Scheme 12: A classical Kabachnik–Fields reaction followed by an intramolecular ring-closing reaction for the s...
Scheme 13: Synthesis of (S)-piperidin-2-phosphonic acid through an asymmetric Kabachnik–Fields reaction.
Scheme 14: A modified diastereoselective Kabachnik–Fields reaction for the synthesis of isoindolin-1-one-3-pho...
Scheme 15: A microwave-assisted Kabachnik–Fields reaction toward isoindolin-1-ones.
Scheme 16: The synthesis of 3-arylmethyleneisoindolin-1-ones through a Horner–Wadsworth–Emmons reaction of Kab...
Scheme 17: An efficient one-pot method for the synthesis of ethyl (2-alkyl- and 2-aryl-3-oxoisoindolin-1-yl)ph...
Scheme 18: FeCl3 and PdCl2 co-catalyzed three-component reaction of 2-alkynylbenzaldehydes, anilines, and diet...
Scheme 19: Three-component reaction of 6-methyl-3-formylchromone (75) with hydrazine derivatives or hydroxylam...
Scheme 20: Three-component reaction of 6-methyl-3-formylchromone (75) with thiourea, guanidinium carbonate or ...
Scheme 21: Three-component reaction of 6-methyl-3-formylchromone (75) with 1,4-bi-nucleophiles in the presence...
Scheme 22: One-pot three-component reaction of 2-alkynylbenzaldehydes, amines, and diethyl phosphonate.
Scheme 23: Lewis acid–surfactant combined catalysts for the one-pot three-component reaction of 2-alkynylbenza...
Scheme 24: Lewis acid catalyzed cyclization of different Kabachnik–Fields adducts.
Scheme 25: Three-component synthesis of N-arylisoquinolone-1-phosphonates 119.
Scheme 26: CuI-catalyzed three-component tandem reaction of 2-(2-formylphenyl)ethanones with aromatic amines a...
Scheme 27: Synthesis of 1,5-benzodiazepin-2-ylphosphonates via ytterbium chloride-catalyzed three-component re...
Scheme 28: FeCl3-catalyzed four-component reaction for the synthesis of 1,5-benzodiazepin-2-ylphosphonates.
Scheme 29: Synthesis of indole bisphosphonates through a modified Kabachnik–Fields reaction.
Scheme 30: Synthesis of heterocyclic bisphosphonates via Kabachnik–Fields reaction of triethyl orthoformate.
Scheme 31: A domino Knoevenagel/phospha-Michael process for the synthesis of 2-oxoindolin-3-ylphosphonates.
Scheme 32: Intramolecular cyclization of phospha-Michael adducts to give dihydropyridinylphosphonates.
Scheme 33: Synthesis of fused phosphonylpyrans via intramolecular cyclization of phospha-Michael adducts.
Scheme 34: InCl3-catalyzed three-component synthesis of (2-amino-3-cyano-4H-chromen-4-yl)phosphonates.
Scheme 35: Synthesis of phosphonodihydropyrans via a domino Knoevenagel/hetero-Diels–Alder process.
Scheme 36: Multicomponent synthesis of phosphonodihydrothiopyrans via a domino Knoevenagel/hetero-Diels–Alder ...
Scheme 37: One-pot four-component synthesis of 1,2-dihydroisoquinolin-1-ylphosphonates under multicatalytic co...
Scheme 38: CuI-catalyzed four-component reactions of methyleneaziridines towards alkylphosphonates.
Scheme 39: Ruthenium–porphyrin complex-catalyzed three-component synthesis of aziridinylphosphonates and its p...
Scheme 40: Copper(I)-catalyzed three-component reaction towards 1,2,3-triazolyl-5-phosphonates.
Scheme 41: Three-component reaction of acylphosphonates, isocyanides and dialkyl acetylenedicarboxylate to aff...
Scheme 42: Synthesis of (4-imino-3,4-dihydroquinazolin-2-yl)phosphonates via an isocyanide-based three-compone...
Scheme 43: Silver-catalyzed three-component synthesis of (2-imidazolin-4-yl)phosphonates.
Scheme 44: Three-component synthesis of phosphonylpyrazoles.
Scheme 45: One-pot three-component synthesis of 3-carbo-5-phosphonylpyrazoles.
Scheme 46: A one-pot two-step method for the synthesis of phosphonylpyrazoles.
Scheme 47: A one-pot method for the synthesis of (5-vinylpyrazolyl)phosphonates.
Scheme 48: Synthesis of 1H-pyrrol-2-ylphosphonates via the [3 + 2] cycloaddition of phosphonate azomethine yli...
Scheme 49: Three-component synthesis of 1H-pyrrol-2-ylphosphonates.
Scheme 50: The classical Reissert reaction.
Scheme 51: One-pot three-component synthesis of N-phosphorylated isoquinolines.
Scheme 52: One-pot three-component synthesis of 1-acyl-1,2-dihydroquinoline-2-phosphonates and 2-acyl-1,2-dihy...
Scheme 53: Three-component reaction of pyridine derivatives with ethyl propiolate and dialkyl phosphonates.
Scheme 54: Three-component reactions for the phosphorylation of benzothiazole and isoquinoline.
Scheme 55: Three-component synthesis of diphenyl [2-(aminocarbonyl)- or [2-(aminothioxomethyl)-1,2-dihydroisoq...
Scheme 56: Three-component stereoselective synthesis of 1,2-dihydroquinolin-2-ylphosphonates and 1,2-dihydrois...
Scheme 57: Diphosphorylation of diazaheterocyclic compounds via a tandem 1,4–1,2 addition of dimethyl trimethy...
Scheme 58: Multicomponent reaction of alkanedials, acetamide and acetyl chloride in the presence of PCl3 and a...
Scheme 59: An oxidative domino three-component synthesis of polyfunctionalized pyridines.
Scheme 60: A sequential one-pot three-component synthesis of polysubstituted pyrroles.
Scheme 61: Three-component decarboxylative coupling of proline with aldehydes and dialkyl phosphites for the s...
Scheme 62: Three-component domino aza-Wittig/phospha-Mannich sequence for the phosphorylation of isatin deriva...
Scheme 63: Stereoselective synthesis of phosphorylated trans-1,5-benzodiazepines via a one-pot three-component...
Scheme 64: One-pot three-component synthesis of phosphorylated 2,6-dioxohexahydropyrimidines.
The search for new amphiphiles: synthesis of a modular, high-throughput library
- George C. Feast,
- Thomas Lepitre,
- Xavier Mulet,
- Charlotte E. Conn,
- Oliver E. Hutt,
- G. Paul Savage and
- Calum J. Drummond
Beilstein J. Org. Chem. 2014, 10, 1578–1588, doi:10.3762/bjoc.10.163
- the diol prior to acylation [32]. For the triple-chained tails, triol 15 was synthesised from tris(hydroxymethyl)methylamine (TRIS) and 4-pentynoic acid using ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ), following a similar method to Pucci et al. (Scheme 2) [33]. TRIS has been used previously
Graphical Abstract
Figure 1: Examples of amphiphile applications.
Figure 2: Upon self-assembly, amphiphiles pack and curve away from (normal phase) or towards (inverse phase) ...
Scheme 1: Synthesis of double-chain, alkyne-tethered tails.
Scheme 2: Synthesis of triple-chain, alkyne-tethered tails.
Figure 3: Azido-sugar head groups used in library.
Scheme 3: Synthesis of azido-xylose.
Figure 4: 24-vial array set up.
Figure 5: Multi-tap vacuum chamber for high-throughput filtering.
Figure 6: Cross-polarised microscopy of (A) glucose 2 × C7, 33, (B) xylose 2 × C7, 53, and (C) lactose 2 × C7...
Figure 7: Differences in head group volume lead to differences in the curvature (and thus liquid-crystalline ...
Tandem Cu-catalyzed ketenimine formation and intramolecular nucleophile capture: Synthesis of 1,2-dihydro-2-iminoquinolines from 1-(o-acetamidophenyl)propargyl alcohols
- Gadi Ranjith Kumar,
- Yalla Kiran Kumar,
- Ruchir Kant and
- Maddi Sridhar Reddy
Beilstein J. Org. Chem. 2014, 10, 1255–1260, doi:10.3762/bjoc.10.125
- materials were selected with the variation in substitution on propargyl alcohols as well as sulfonyl azides. It was found that the cascade process was applicable for a wide range of substrates providing the dihydroquinoline derivatives 9 in yields ranging from 36% to 77% (Scheme 3). Initially, we screened 2
Graphical Abstract
Scheme 1: Synthesis of unsaturated amides via ketenimine formation.
Scheme 2: Intramolecular nucleophilic capture by ketenimines.
Scheme 3: Synthesis of 1,2-dihydro-2-tosyliminoquinolines. Reaction conditions: Sulfonyl azide (1.2 mmol), 2 ...
Figure 1: X-ray Structure of 9j (CCDC number 971729).
Copper–phenanthroline catalysts for regioselective synthesis of pyrrolo[3′,4′:3,4]pyrrolo[1,2-a]furoquinolines/phenanthrolines and of pyrrolo[1,2-a]phenanthrolines under mild conditions
- Rupankar Paira,
- Tarique Anwar,
- Maitreyee Banerjee,
- Yogesh P. Bharitkar,
- Shyamal Mondal,
- Sandip Kundu,
- Abhijit Hazra,
- Prakas R. Maulik and
- Nirup B. Mondal
Beilstein J. Org. Chem. 2014, 10, 692–700, doi:10.3762/bjoc.10.62
- carbon signals appearing at δ 101.6 and 110.8 could be assigned to the CH units present in the dihydroquinoline ring. Moreover, the presence of peaks for three carbonyl carbons at δ 174.9, 176.6, 194.5, and for ten other quaternary carbons and 19 methine carbons in the aromatic region (δ 116.0–159.8
Graphical Abstract
Scheme 1: Preparation of maleimide dipolarophiles 4a–c.
Scheme 2: Preparation of 1,3-dipole precursors 9a–d.
Figure 1: Bi-/tridentate ligands used for the optimization of the reaction conditions.
Figure 2: ORTEP diagram showing the molecular structure of 10a at 30% probability level.
Scheme 3: Plausible mechanistic pathway for the synthesis of pyrrolo[3′,4′:3,4]pyrrolo[1,2-a]furoquinolines.
Scheme 4: Synthesis of pyrrolo[3′,4′:3,4]pyrrolo[1,2-a]furoquinoline analogues under the optimized protocol.
Scheme 5: Construction of pyrrolo[3′,4′:3,4]pyrrolo[1,2-a]phenanthrolines 14a–c and of pyrrolo[1,2-a]phenanth...
Figure 3: ORTEP diagram showing the molecular structure of 14e at 30% probability level.
An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles
- Marcus Baumann and
- Ian R. Baxendale
Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265
- phenylalanine residue as well as through several H-bonds facilitated by the adjacent polar substituents (Figure 8). The reported synthesis of carmegliptin enlists a Bischler-Napieralski reaction utilising the primary amine 2.76 and methyl formate to yield the initial dihydroquinoline 2.77 as its HCl salt
Graphical Abstract
Scheme 1: Scaled industrial processes for the synthesis of simple pyridines.
Scheme 2: Synthesis of nicotinic acid from 2-methyl-5-ethylpyridine (1.11).
Scheme 3: Synthesis of 3-picoline and nicotinic acid.
Scheme 4: Synthesis of 3-picoline from 2-methylglutarodinitrile 1.19.
Scheme 5: Picoline-based synthesis of clarinex (no yields reported).
Scheme 6: Mode of action of proton-pump inhibitors and structures of the API’s.
Scheme 7: Hantzsch-like route towards the pyridine rings in common proton pump inhibitors.
Figure 1: Structures of rosiglitazone (1.40) and pioglitazone (1.41).
Scheme 8: Synthesis of rosiglitazone.
Scheme 9: Syntheses of 2-pyridones.
Scheme 10: Synthesis and mechanism of 2-pyrone from malic acid.
Scheme 11: Polymer-assisted synthesis of rosiglitazone.
Scheme 12: Synthesis of pioglitazone.
Scheme 13: Meerwein arylation reaction towards pioglitazone.
Scheme 14: Route towards pioglitazone utilising tyrosine.
Scheme 15: Route towards pioglitazone via Darzens ester formation.
Scheme 16: Syntheses of the thiazolidinedione moiety.
Scheme 17: Synthesis of etoricoxib utilising Negishi and Stille cross-coupling reactions.
Scheme 18: Synthesis of etoricoxib via vinamidinium condensation.
Figure 2: Structures of nalidixic acid, levofloxacin and moxifloxacin.
Scheme 19: Synthesis of moxifloxacin.
Scheme 20: Synthesis of (S,S)-2,8-diazabicyclo[4.3.0]nonane 1.105.
Scheme 21: Synthesis of levofloxacin.
Scheme 22: Alternative approach to the levofloxacin core 1.125.
Figure 3: Structures of nifedipine, amlodipine and clevidipine.
Scheme 23: Mg3N2-mediated synthesis of nifedipine.
Scheme 24: Synthesis of rac-amlodipine as besylate salt.
Scheme 25: Aza Diels–Alder approach towards amlodipine.
Scheme 26: Routes towards clevidipine.
Figure 4: Examples of piperidine containing drugs.
Figure 5: Discovery of tiagabine based on early leads.
Scheme 27: Synthetic sequences to tiagabine.
Figure 6: Structures of solifenacin (2.57) and muscarine (2.58).
Scheme 28: Enantioselective synthesis of solifenacin.
Figure 7: Structures of DPP-4 inhibitors of the gliptin-type.
Scheme 29: Formation of inactive diketopiperazines from cis-rotameric precursors.
Figure 8: Co-crystal structure of carmegliptin bound in the human DPP-4 active site (PDB 3kwf).
Scheme 30: Improved route to carmegliptin.
Figure 9: Structures of lamivudine and zidovudine.
Scheme 31: Typical routes accessing uracil, thymine and cytosine.
Scheme 32: Coupling between pyrimidones and riboses via the Vorbrüggen nucleosidation.
Scheme 33: Synthesis of lamivudine.
Scheme 34: Synthesis of raltegravir.
Scheme 35: Mechanistic studies on the formation of 3.22.
Figure 10: Structures of selected pyrimidine containing drugs.
Scheme 36: General preparation of pyrimidines and dihydropyrimidones.
Scheme 37: Synthesis of imatinib.
Scheme 38: Flow synthesis of imatinib.
Scheme 39: Syntheses of erlotinib.
Scheme 40: Synthesis of erlotinib proceeding via Dimroth rearrangement.
Scheme 41: Synthesis of lapatinib.
Scheme 42: Synthesis of rosuvastatin.
Scheme 43: Alternative preparation of the key aldehyde towards rosuvastatin.
Figure 11: Structure comparison between nicotinic acetylcholine receptor agonists.
Scheme 44: Syntheses of varenicline and its key building block 4.5.
Scheme 45: Synthetic access to eszopiclone and brimonidine via quinoxaline intermediates.
Figure 12: Bortezomib bound in an active site of the yeast 20S proteasome ([114], pdb 2F16).
Scheme 46: Asymmetric synthesis of bortezomib.
Figure 13: Structures of some prominent piperazine containing drugs.
Figure 14: Structural comparison between the core of aplaviroc (4.35) and a type-1 β-turn (4.36).
Scheme 47: Examplary synthesis of an aplaviroc analogue via the Ugi-MCR.
Scheme 48: Syntheses of azelastine (5.1).
Figure 15: Structures of captopril, enalapril and cilazapril.
Scheme 49: Synthesis of cilazapril.
Figure 16: Structures of lamotrigine, ceftriaxone and azapropazone.
Scheme 50: Synthesis of lamotrigine.
Scheme 51: Alternative synthesis of lamotrigine (no yields reported).
Figure 17: Structural comparison between imiquimod and the related adenosine nucleoside.
Scheme 52: Conventional synthesis of imiquimod (no yields reported).
Scheme 53: Synthesis of imiquimod.
Scheme 54: Synthesis of imiquimod via tetrazole formation (not all yields reported).
Figure 18: Structures of various anti HIV-medications.
Scheme 55: Synthesis of abacavir.
Figure 19: Structures of diazepam compared to modern replacements.
Scheme 56: Synthesis of ocinaplon.
Scheme 57: Access to zaleplon and indiplon.
Scheme 58: Different routes towards the required N-methylpyrazole 6.65 of sildenafil.
Scheme 59: Polymer-supported reagents in the synthesis of key aminopyrazole 6.72.
Scheme 60: Early synthetic route to sildenafil.
Scheme 61: Convergent preparations of sildenafil.
Figure 20: Comparison of the structures of sildenafil, tadalafil and vardenafil.
Scheme 62: Short route to imidazotriazinones.
Scheme 63: Alternative route towards vardenafils core imidazotriazinone (6.95).
Scheme 64: Bayer’s approach to the vardenafil core.
Scheme 65: Large scale synthesis of vardenafil.
Scheme 66: Mode of action of temozolomide (6.105) as methylating agent.
Scheme 67: Different routes to temozolomide.
Scheme 68: Safer route towards temozolomide.
Figure 21: Some unreported heterocyclic scaffolds in top market drugs.
Gold(I)-catalyzed hydroarylation reaction of aryl (3-iodoprop-2-yn-1-yl) ethers: synthesis of 3-iodo-2H-chromene derivatives
- Pablo Morán-Poladura,
- Eduardo Rubio and
- José M. González
Beilstein J. Org. Chem. 2013, 9, 2120–2128, doi:10.3762/bjoc.9.249
- proposed to mediate related hydroarylation reactions affording halogenated phenanthrenes [45] and 3-iodo-N-tosyl-1,2-dihydroquinoline derivatives [43]. Recent studies have provided strong evidence for their existence, and have demonstrated their powerful reactivity [51][52][53][54][55], identifying them as
Graphical Abstract
Scheme 1: Synthesis of 3-halo-2H-chromenes.
Figure 1: X-ray molecular structure of 2f.
Scheme 2: Gram-scale synthesis of 2f.
Scheme 3: Retaining propargylic chirality.
Scheme 4: Mechanistic basis postulated for the synthesis of 2.
The multicomponent approach to N-methyl peptides: total synthesis of antibacterial (–)-viridic acid and analogues
- Ricardo A. W. Neves Filho,
- Sebastian Stark,
- Bernhard Westermann and
- Ludger A. Wessjohann
Beilstein J. Org. Chem. 2012, 8, 2085–2090, doi:10.3762/bjoc.8.234
- -ethoxy-1,2-dihydroquinoline (EEDQ) as coupling reagent, which gave the optically active tripeptide 7 in 51% yield [16][17]. Intermediate 7 was converted into amine 8 under acidic conditions, and coupled directly to N,N-dimethylanthranilic acid (9). It was already reported that carbodiimide-mediated
Graphical Abstract
Scheme 1: Retrosynthetic strategies for (−)-viridic acid (1) and analogues by (a) a bidirectional peptide-cou...
Scheme 2: Reactions and conditions: (a) Boc-Gly-OH, EDCI, HOAt, TEA, CH2Cl2, rt, 20 h, 73%. (b) LiOH, THF/H2O...
Scheme 3: Reactions and conditions: (a) H-Gly-OBn·HCl, NMM, ethyl chloroformate, CHCl3, 18 h, rt, 88%. (b) H2...
Organocatalytic tandem Michael addition reactions: A powerful access to the enantioselective synthesis of functionalized chromenes, thiochromenes and 1,2-dihydroquinolines
- Chittaranjan Bhanja,
- Satyaban Jena,
- Sabita Nayak and
- Seetaram Mohapatra
Beilstein J. Org. Chem. 2012, 8, 1668–1694, doi:10.3762/bjoc.8.191
- the construction of 1,2-dihydroquinoline derivatives. In their protocol, the reaction of 2-N-protected aminobenzaldehydes 54 with α,β-unsaturated aldehydes 2 promoted by (S)-diphenylprolinol TES ether Ie in the presence of NaOAc afforded the pharmaceutically valuable chiral 1,2-dihydroquinolines 55
- reaction time. By taking advantage of the above methodology, Hamada et al. [75] in 2008 reported a similar type of reaction for the construction of the 1,2-dihydroquinoline chiral core of martinelline (a nonpeptide bradykinin receptor antagonist) and its diastereoisomer. Using a domino aza-Michael–aldol
Graphical Abstract
Figure 1: Some representative molecules having chromene, thiochromene or 1,2-dihydroquinolin structural motif...
Figure 2: Screened chiral proline and its derivatives as organocatalysts. Rb = rubidium.
Figure 3: Screened chiral bifunctional thiourea, its derivatives, cinchona alkaloids and other organocatalyst...
Scheme 1: Diarylprolinolether-catalyzed tandem oxa-Michael–aldol reaction reported by Arvidsson.
Scheme 2: Tandem oxa-Michael–aldol reaction developed by Córdova.
Scheme 3: Domino oxa-Michael-aldol reaction developed by Wei and Wang.
Scheme 4: Chiral amine/chiral acid catalyzed tandem oxa-Michael–aldol reaction developed by Xu et al.
Scheme 5: Modified diarylproline ether as amino catalyst in oxa-Michael–aldol reaction as reported by Xu and ...
Scheme 6: Chiral secondary amine promoted oxa-Michael–aldol cascade reactions as reported by Wang and co-work...
Scheme 7: Reaction of salicyl-N-tosylimine with aldehydes by domino oxa-Michael/aza-Baylis–Hillman reaction, ...
Scheme 8: Silyl prolinol ether-catalyzed oxa-Michael–aldol tandem reaction of alkynals with salicylaldehydes ...
Scheme 9: Oxa-Michael–aldol sequence for the synthesis of tetrahydroxanthones developed by Córdova.
Scheme 10: Synthesis of tetrahydroxanthones developed by Xu.
Scheme 11: Diphenylpyrrolinol trimethylsilyl ether catalyzed oxa-Michael–Michael–Michael–aldol reaction for th...
Scheme 12: Enantioselective cascade oxa-Michael–Michael reaction of alkynals with 2-(E)-(2-nitrovinyl)-phenols...
Scheme 13: Domino oxa-Michael–Michael–Michael–aldol reaction of 2-(2-nitrovinyl)-benzene-1,4-diol with α,β-uns...
Scheme 14: Tandem oxa-Michael–Henry reaction catalyzed by organocatalyst and salicylic acid, as reported by Xu....
Scheme 15: Asymmetric synthesis of nitrochromenes from salicylaldehydes and β-nitrostyrene, as reported by San...
Scheme 16: Domino Michael–aldol reaction between salicyaldehydes with β-nitrostyrene, as reported by Das and c...
Scheme 17: Enantioselective synthesis of 2-aryl-3-nitro-2H-chromenes, as reported by Schreiner.
Scheme 18: (S)-diphenylpyrrolinol silyl ether-promoted cascade thio-Michael–aldol reactions, as reported by Wa...
Scheme 19: Organocatalytic asymmetric domino Michael–aldol condensation of mercaptobenzaldehyde and α,β-unsatu...
Scheme 20: Organocatalytic asymmetric domino Michael–aldol condensation between mercaptobenzaldehyde and α,β-u...
Scheme 21: Hydrogen-bond-mediated Michael–aldol reaction of 2-mercaptobenzaldehyde with α,β-unsaturated oxazol...
Scheme 22: Domino Michael–aldol reaction of 2-mercaptobenzaldehydes with maleimides catalyzed by cinchona alka...
Scheme 23: Domino thio-Michael–aldol reaction between 2-mercaptoacetophenone and enals developed by Córdova an...
Scheme 24: Enantioselective tandem Michael–Henry reaction of 2-mercaptobenzaldehyde with β-nitrostyrenes repor...
Scheme 25: Enantioselective tandem Michael–Knoevenagel reaction between 2-mercaptobenzaldehydes and benzyliden...
Scheme 26: Cinchona alkaloid thiourea catalyzed Michael–Michael cascade reaction, as reported by Wang and co-w...
Scheme 27: Domino aza-Michael–aldol reaction between 2-aminobenzaldehydes and α,β-unsaturated aldehydes, as re...
Scheme 28: (S)-Diphenylprolinol TES ether-promoted aza-Michael–aldol cascade reaction, as developed by Wang’s ...
Scheme 29: Domino aza-Michael–aldol reaction reported by Hamada.
Scheme 30: Organocatalytic asymmetric synthesis of 3-nitro-1,2-dihydroquinolines by a dual activation protocol...
Scheme 31: Asymmetric synthesis of 3-nitro-1,2-dihydroquinolines by cascade aza-Michael–Henry–dehydration reac...
Multicomponent reaction access to complex quinolines via oxidation of the Povarov adducts
- Esther Vicente-García,
- Rosario Ramón,
- Sara Preciado and
- Rodolfo Lavilla
Beilstein J. Org. Chem. 2011, 7, 980–987, doi:10.3762/bjoc.7.110
- and amine moieties, leading to dihydroquinoline intermediates that, after spontaneous oxidation in air, provide the final fragmented quinolines. The ability of DDQ to act as a Lewis acid and promote this alternative pathway has some precedent in the literature [19]. Furthermore, TFA treatment of
Graphical Abstract
Scheme 1: Povarov oxidation access to substituted quinolines.
Scheme 2: Tetrahydroquinoline oxidation.
Scheme 3: Synthesis of the Povarov adducts and their oxidation products.
Figure 1: Optimization of the reaction conditions for the preparation of quinoline 18.
Scheme 4: Oxidation of lactam-fused tetrahydroquinolines 20,20'.
Recent advances in the gold-catalyzed additions to C–C multiple bonds
- He Huang,
- Yu Zhou and
- Hong Liu
Beilstein J. Org. Chem. 2011, 7, 897–936, doi:10.3762/bjoc.7.103
- by the AuCl3/AgSbF6 catalyst and ionization of the starting material, which causes intramolecular nucleophilic addition of the sulfonamide unit to the allylic cation moiety and construction of a 1,2-dihydroquinoline. Our group also discovered that a regioselective hydroamidation of 2-(1-alkynyl
Graphical Abstract
Scheme 1: Gold-catalyzed addition of alcohols.
Scheme 2: Gold-catalyzed cycloaddition of alcohols.
Scheme 3: Ionic liquids as the solvent in gold-catalyzed cycloaddition.
Scheme 4: Gold-catalyzed cycloaddition of diynes.
Scheme 5: Gold(I) chloride catalyzed cycloisomerization of 2-alkynyl-1,5-diols.
Scheme 6: Gold-catalyzed cycloaddition of glycols and dihydroxy compounds.
Scheme 7: Gold-catalyzed ring-opening of cyclopropenes.
Scheme 8: Gold-catalyzed intermolecular hydroalkoxylation of alkynes. PR3 = 41–45.
Scheme 9: Gold-catalyzed intramolecular 6-endo-dig cyclization of β-hydroxy-α,α-difluoroynones.
Scheme 10: Gold-catalyzed intermolecular hydroalkoxylation of non-activated olefins.
Scheme 11: Preparation of unsymmetrical ethers from alcohols.
Scheme 12: Expedient synthesis of dihydrofuran-3-ones.
Scheme 13: Catalytic approach to functionalized divinyl ketones.
Scheme 14: Gold-catalyzed glycosylation.
Scheme 15: Gold-catalyzed cycloaddition of aldehydes and ketones.
Scheme 16: Gold-catalyzed annulations of 2-(ynol)aryl aldehydes and o-alkynyl benzaldehydes.
Scheme 17: Gold-catalyzed addition of carboxylates.
Scheme 18: Dual-catalyzed rearrangement reaction of allenoates.
Scheme 19: Meyer–Schuster rearrangement of propargylic alcohols.
Scheme 20: Propargylic alcohol rearrangements.
Scheme 21: Gold-catalyzed synthesis of imines and amine alkylation.
Scheme 22: Hydroamination of allenes and allenamides.
Scheme 23: Gold-catalyzed inter- and intramolecular amination of alkynes and alkenes.
Scheme 24: Gold-catalyzed cycloisomerization of O-propioloyl oximes and β-allenylhydrazones.
Scheme 25: Intra- and intermolecular amination with ureas.
Scheme 26: Gold-catalyzed cyclization of ortho-alkynyl-N-sulfonylanilines and but-3-yn-1-amines.
Scheme 27: Gold-catalyzed piperidine ring synthesis.
Scheme 28: Ring expansion of alkylnyl cyclopropanes.
Scheme 29: Gold-catalyzed annulations of N-propargyl-β-enaminones and azomethine imines.
Scheme 30: Gold(I)-catalyzed cycloisomerization of aziridines.
Scheme 31: AuCl3/AgSbF6-catalyzed intramolecular amination of 2-(tosylamino)phenylprop-1-en-3-ols.
Scheme 32: Gold-catalyzed cyclization via a 7-endo-dig pathway.
Scheme 33: Gold-catalyzed synthesis of fused xanthines.
Scheme 34: Gold-catalyzed synthesis of amides and isoquinolines.
Scheme 35: Gold-catalyzed oxidative cross-coupling reactions of propargylic acetates.
Scheme 36: Gold-catalyzed nucleophilic addition to allenamides.
Scheme 37: Gold-catalyzed direct carbon–carbon bond coupling reactions.
Scheme 38: Gold-catalyzed C−H functionalization of indole/pyrrole heterocycles and non-activated arenes.
Scheme 39: Gold-catalyzed cycloisomerization of cyclic compounds.
Scheme 40: Gold-catalyzed cycloaddition of 1-aryl-1-allen-6-enes and propargyl acetates.
Scheme 41: Gold(I)-catalyzed cycloaddition with ligand-controlled regiochemistry.
Scheme 42: Gold(I)-catalyzed cycloaddition of dienes and enynes.
Scheme 43: Gold-catalyzed intramolecular cycloaddition of 3-alkoxy-1,5-enynes and 2,2-dipropargylmalonates.
Scheme 44: Gold-catalyzed intramolecular cycloaddition of 1,5-allenynes.
Scheme 45: Gold(I)-catalyzed cycloaddition of indoles.
Scheme 46: Gold-catalyzed annulation reactions.
Scheme 47: Gold–carbenoid induced cleavage of a sp3-hybridized C−H bond.
Scheme 48: Furan- and indole-based cascade reactions.
Scheme 49: Tandem process using aromatic alkynes.
Scheme 50: Gold-catalyzed cycloaddition of 1,3-dien-5-ynes.
Scheme 51: Gold-catalyzed cascade cyclization of diynes, propargylic esters, and 1,3-enynyl ketones.
Scheme 52: Tandem reaction of β-phenoxyimino ketones and alkynyl oxime ethers.
Scheme 53: Gold-catalyzed tandem cyclization of enynes, 2-(tosylamino)phenylprop-1-yn-3-ols, and allenoates.
Scheme 54: Cyclization of 2,4-dien-6-yne carboxylic acids.
Scheme 55: Gold(I)-catalyzed tandem cyclization approach to tetracyclic indolines.
Scheme 56: Gold-catalyzed tandem reactions of alkynes.
Scheme 57: Aminoarylation and oxyarylation of alkenes.
Scheme 58: Cycloaddition of 2-ethynylnitrobenzene with various alkenes.
Scheme 59: Gold-catalyzed tandem reactions of allenoates and alkynes.
Scheme 60: Gold-catalyzed asymmetric synthesis of 2,3-dihydropyrroles.
Scheme 61: Chiral [NHC–Au(I)]-catalyzed cyclization of enyne.
Scheme 62: Gold-catalyzed hydroaminations and hydroalkoxylations.
Scheme 63: Gold(I)-catalyzed asymmetric hydroalkoxylation of 1,3-dihydroxymethyl-2-alkynylbenzene chromium com...
Scheme 64: Gold-catalyzed synthesis of julolidine derivatives.
Scheme 65: Gold-catalyzed the synthesis of chiral fused heterocycles.
Scheme 66: Gold-catalyzed asymmetric reactions with 3,5-(t-Bu)2-4-MeO-MeOBIPHEP.
Scheme 67: Gold-catalyzed cyclization of o-(alkynyl) styrenes.
Scheme 68: Asymmetric gold(I)-catalyzed redox-neutral domino reactions of enynes.
Scheme 69: Gold(I)-catalyzed enantioselective polyene cyclization reaction.
Scheme 70: Gold(I)-catalyzed enantioselective synthesis of benzopyrans.
Scheme 71: Gold(I)-catalyzed enantioselective ring expansion of allenylcyclopropanols.
