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Search for "primary amine" in Full Text gives 169 result(s) in Beilstein Journal of Organic Chemistry.
A straightforward approach towards combined α-amino and α-hydroxy acids based on Passerini reactions
- Ameer F. Zahoor,
- Sarah Thies and
- Uli Kazmaier
Beilstein J. Org. Chem. 2011, 7, 1299–1303, doi:10.3762/bjoc.7.151
- powerful tool for the synthesis of acylated α-hydroxyacid amides [10]. Later on, in 1961, Ugi and Steinbrückner reported the extension of this protocol by incorporating also a primary amine as a fourth component [11]. Therefore, the Ugi reaction is even more flexible than the Passerini approach, but both
Graphical Abstract
Scheme 1: Passerini reactions of α,β-unsaturated aldehyde 5.
Scheme 2: Passerini and Ugi reaction of saturated aldehyde 7.
Reductive amination with zinc powder in aqueous media
- Giovanni B. Giovenzana,
- Daniela Imperio,
- Andrea Penoni and
- Giovanni Palmisano
Beilstein J. Org. Chem. 2011, 7, 1095–1099, doi:10.3762/bjoc.7.125
- process could be considerably simplified by the development of a one-pot procedure involving the combination of a primary amine, aldehyde, and zinc in water, thereby avoiding the isolation of the intermediate imine. Although this combination appears to be plausible, its success is far from obvious: i) the
Graphical Abstract
Scheme 1: Reductive amination with zinc in aqueous base solution.
Homoallylic amines by reductive inter- and intramolecular coupling of allenes and nitriles
- Peter Wipf and
- Marija D. Manojlovic
Beilstein J. Org. Chem. 2011, 7, 824–830, doi:10.3762/bjoc.7.94
- methodology, we demonstrated that the homoallylic amine products could be readily converted to synthetically useful building blocks, such as β-amino acids (Scheme 4). N-Boc-protection of the primary amine 12 followed by ozonolysis under Marshall’s conditions [40] yielded the β-amino acid derivative 24. The
Graphical Abstract
Scheme 1: One-pot hydrozirconation-reductive coupling of allene 2 and nitrile 7.
Scheme 2: Cyclization of allenylnitrile 18.
Figure 1: Coupling constant analysis of the Boc-protected aminopyran ring in 21.
Scheme 3: Proposed chelated transition state model.
Scheme 4: Conversion of homoallylic amines to β-amino acid derivatives.
An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals
- Marcus Baumann,
- Ian R. Baxendale,
- Steven V. Ley and
- Nikzad Nikbin
Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57
- synthetic approach was based on the classical Paal–Knorr cyclocondensation of a highly substituted 1,4-diketone with a primary amine bearing a masked aldehyde functionality. The 1,4-diketone component, which can be accessed via a 3-step sequence [5] starting from aniline, was refluxed with 3
- the indole ring and the pendant primary amine group in a single operation (Scheme 17). However, the main disadvantage of this process is the need for high temperatures which leads to the formation of dimeric impurities and results in the requirement for extensive chromatographic purification. An
Graphical Abstract
Figure 1: Structures of atorvastatin and other commercial statins.
Figure 2: Structure of compactin.
Scheme 1: Synthesis of pentasubstituted pyrroles.
Scheme 2: [3 + 2] Cycloaddition to prepare 5-isopropylpyrroles.
Scheme 3: Regiospecific [3 + 2] cycloaddition to prepare the pyrrole scaffold.
Scheme 4: Formation of the pyrrole core of atorvastatin via [3 + 2] cycloaddition.
Scheme 5: Formation of pyrrole 33 via the Paal–Knorr reaction.
Scheme 6: Convergent synthesis towards atorvastatin.
Figure 3: Binding pocket of sunitinib in the TRK KIT.
Scheme 7: Synthesis of sunitinib.
Scheme 8: Alternative synthesis of sunitinib.
Scheme 9: Key steps in the syntheses of sumatriptan and zolmitriptan.
Scheme 10: Introduction of the N,N-dimethylaminoethyl side chain.
Scheme 11: Japp–Klingemann reaction in the synthesis of sumatriptan.
Scheme 12: Synthesis of the intermediate sulfonyl chlorides 62 and 63.
Scheme 13: Alternative introduction of the sulfonamide.
Scheme 14: Negishi-type coupling to benzylic sulfonamides.
Scheme 15: Heck reaction used to introduce the sulfonamide side chain of naratriptan.
Scheme 16: Synthesis of the oxazolinone appendage of zolmitriptan.
Scheme 17: Grandberg indole synthesis used in the preparation of rizatriptan.
Scheme 18: Improved synthesis of rizatriptan.
Scheme 19: Larock-type synthesis of rizatriptan.
Scheme 20: Synthesis of eletriptan.
Scheme 21: Heck coupling for the indole system in eletriptan.
Scheme 22: Attempted Fischer indole synthesis of elatriptan.
Scheme 23: Successful Fischer indole synthesis for eletriptan.
Scheme 24: Mechanistic rationale for the Bischler–Möhlau reaction.
Scheme 25: Bischler-type indole synthesis used in the fluvastatin sodium synthesis.
Scheme 26: Palladium-mediated synthesis of ondansetron.
Scheme 27: Fischer indole synthesis of ondansetron.
Scheme 28: Optimised Pictet–Spengler reaction towards tadalafil.
Figure 4: Structures of carvedilol 136 and propranolol 137.
Scheme 29: Synthesis of the carbazole core of carvedilol.
Scheme 30: Alternative syntheses of 4-hydroxy-9H-carbazole.
Scheme 31: Convergent synthesis of etodolac.
Scheme 32: Alternative synthesis of etodolac.
Figure 5: Structures of imidazole-containing drugs.
Scheme 33: Synthesis of functionalised imidazoles towards losartan.
Scheme 34: Direct synthesis of the chlorinated imidazole in losartan.
Scheme 35: Synthesis of trisubstituted imidazoles.
Scheme 36: Preparation of the imidazole ring in olmesartan.
Scheme 37: Synthesis of ondansetron.
Scheme 38: Alternative route to ondansetron and its analogues.
Scheme 39: Proton pump inhibitors and synthesis of esomeprazole.
Scheme 40: Synthesis of benzimidazole core pantoprazole.
Figure 6: Structure of rabeprazole 194.
Scheme 41: Synthesis of candesartan.
Scheme 42: Alternative access to the candesartan key intermediate 216.
Scheme 43: .Medicinal chemistry route to telmisartan.
Scheme 44: Improved synthesis of telmisartan.
Scheme 45: Synthesis of zolpidem.
Scheme 46: Copper-catalysed 3-component coupling towards zolpidem.
Figure 7: Structure of celecoxib.
Scheme 47: Preparation of celecoxib.
Scheme 48: Alternative synthesis of celecoxib.
Scheme 49: Regioselective access to celecoxib.
Scheme 50: Synthesis of pazopanib.
Scheme 51: Syntheses of anastrozole, rizatriptan and letrozole.
Scheme 52: Regioselective synthesis of anastrozole.
Scheme 53: Triazine-mediated triazole formation towards anastrozole.
Scheme 54: Alternative routes to 1,2,4-triazoles.
Scheme 55: Initial synthetic route to sitagliptin.
Figure 8: Binding of sitagliptin within DPP-IV.
Scheme 56: The process route to sitagliptin key intermediate 280.
Scheme 57: Synthesis of maraviroc.
Scheme 58: Synthesis of alprazolam.
Scheme 59: The use of N-nitrosoamidine derivatives in the preparation of fused benzodiazepines.
Figure 9: Structures of itraconazole, ravuconazole and voriconazole.
Scheme 60: Synthesis of itraconazole.
Scheme 61: Synthesis of rufinamide.
Scheme 62: Representative tetrazole formation in valsartan.
Figure 10: Structure of tetrazole containing olmesartan, candesartan and irbesartan.
Scheme 63: Early stage introduction of the tetrazole in losartan.
Scheme 64: Synthesis of cilostazol.
Figure 11: Structure of cefdinir.
Scheme 65: Semi-synthesis of cefdinir.
Scheme 66: Thiazole syntheses towards ritonavir.
Scheme 67: Synthesis towards pramipexole.
Scheme 68: Alternative route to pramipexole.
Scheme 69: Synthesis of famotidine.
Scheme 70: Efficient synthesis of the hyperuricemic febuxostat.
Scheme 71: Synthesis of ziprasidone.
Figure 12: Structure of mometasone.
Scheme 72: Industrial access to 2-furoic acid present in mometasone.
Scheme 73: Synthesis of ranitidine from furfuryl alcohol.
Scheme 74: Synthesis of nitrofurantoin.
Scheme 75: Synthesis of benzofuran.
Scheme 76: Synthesis of amiodarone.
Scheme 77: Synthesis of raloxifene.
Scheme 78: Alternative access to the benzo[b]thiophene core of raloxifene.
Scheme 79: Gewald reaction in the synthesis of olanzapine.
Scheme 80: Alternative synthesis of olanzapine.
Figure 13: Access to simple thiophene-containing drugs.
Scheme 81: Synthesis of clopidogrel.
Scheme 82: Pictet–Spengler reaction in the preparation of tetrahydrothieno[3,2-c]pyridine (422).
Scheme 83: Alternative synthesis of key intermediate 422.
Figure 14: Co-crystal structures of timolol (left) and carazolol (right) in the β-adrenergic receptor.
Scheme 84: Synthesis of timolol.
Scheme 85: Synthesis of tizanidine 440.
Scheme 86: Synthesis of leflunomide.
Scheme 87: Synthesis of sulfamethoxazole.
Scheme 88: Synthesis of risperidone.
Figure 15: Relative abundance of selected transformations.
Figure 16: The abundance of heterocycles within top 200 drugs (5-membered rings).
Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds
- Carolin Fischer and
- Burkhard Koenig
Beilstein J. Org. Chem. 2011, 7, 59–74, doi:10.3762/bjoc.7.10
- catalytic synthetic sequence is an inexpensive and efficient route to the target compounds (Scheme 12) [64]. A three-component coupling reaction of 2-bromobenzenethiol 57, a primary amine 58 and 1-bromo-2-iodobenzenes 59, also targeting promazine derivatives 60, was successfully under palladium catalysis
Graphical Abstract
Scheme 1: Synthesis of selective D3 receptor ligands.
Scheme 2: Synthesis of a novel 5-HT1B receptor antagonist.
Scheme 3: Synthesis of A-366833, a selective α4β2 neural nicotinic receptor agonist.
Scheme 4: A new route to oxcarbazepine.
Scheme 5: Synthesis of key intermediates for norepinephrine transporter (NET) inhibitors.
Scheme 6: N-Annulation yielding substituted indole for the synthesis of demethylasterriquinone A1.
Scheme 7: Palladium-catalysed double N-arylation contributing to the synthesis of murrazoline.
Scheme 8: Synthesis of vitamin E amines.
Scheme 9: Improved synthesis of martinellic acid.
Scheme 10: New tariquidar-derived ABCB1 inhibitors.
Scheme 11: β-Carbolin-1-ones as inhibitors of tumour cell proliferation.
Scheme 12: Copper-catalysed synthesis of promazine drugs.
Scheme 13: Palladium-catalysed multicomponent reaction for the synthesis of promazine drugs.
Scheme 14: Key intermediate for imatinib.
Scheme 15: Synthesis of an effective Chek1/KDR kinase inhibitor.
Scheme 16: Macrocyclization as final step of the synthesis of heat shock protein inhibitor.
Scheme 17: Synthesis of N-arylimidazoles.
Scheme 18: Synthesis of benzolactam V8.
Scheme 19: Synthesis of an intermediate for lotrafiban (SB-214857).
Scheme 20: Intermolecular effort towards lotrafiban.
Scheme 21: Synthesis of matrix metalloproteases (MMPs) inhibitor.
Scheme 22: Regioselective 9-N-arylation of purines.
Scheme 23: N-Arylation of adenine and cytosine.
Scheme 24: 9-N-Arylpurines as enterovirus inhibitors.
Scheme 25: Xanthine analogues as kinase inhibitors.
Scheme 26: Synthesis of dual PPARα/γ agonists.
Scheme 27: N-Aryltriazole ribonucleosides with anti-proliferative activity.
Hybrid biofunctional nanostructures as stimuli-responsive catalytic systems
- Gernot U. Marten,
- Thorsten Gelbrich and
- Annette M. Schmidt
Beilstein J. Org. Chem. 2010, 6, 922–931, doi:10.3762/bjoc.6.98
- methacrylate (SIMA (S), Figure 1) as an active ester-functional monomer in DMSO by using surface-modified Fe3O4 nanoparticles as macroinitiators (Scheme 1). Subsequently, subunits carrying primary amine groups, such as proteins or enzymes, can be immobilized via the active ester pendant groups of the brush
Graphical Abstract
Scheme 1: Synthesis of magnetic biocatalyst particles.
Figure 1: Structures of comonomers employed in the synthesis of functional core–shell particles.
Figure 2: TEM images of a) Fe3O4 nanoparticles electrostatically stabilized by citric acid; b) Fe3O4@P(M100) ...
Figure 3: a) Cloud point temperature Tc of Fe3O4@P(OxMy) in water in relation to molar fraction of MEMA χM,ex...
Figure 4: a) Normalized magnetization loops of dispersions based on Fe3O4@CA in water (solid line), Fe3O4@CPS...
Scheme 2:
Reaction scheme of the enzymatic digestion of BAPNA catalyzed by magnetically labeled trypsin (![[Graphic 1]](/bjoc/content/inline/1860-5397-6-98-i6.png?max-width=637&scale=0.1536366)
).
Figure 5: a) Cornish-Bowden diagram for the temperature-dependent kinetic data of trypsin activity, and b) Ea...
Scheme 3: Proposed mechanism of catalytic activity after heating magnetic biocatalyst particles above Tc.
Figure 6: a) Turnover number kcat and b) Michaelis constant Km of particle- immobilized trypsin vs free tryps...
Molecular recognition of organic ammonium ions in solution using synthetic receptors
- Andreas Späth and
- Burkhard König
Beilstein J. Org. Chem. 2010, 6, No. 32, doi:10.3762/bjoc.6.32
Graphical Abstract
Figure 1: Biologically important amines and quaternary ammonium salts: histamine (1), dopamine (2) and acetyl...
Figure 2: Crown ether 18-crown-6.
Figure 3: Conformations of 18-crown-6 (4) in solvents of different polarity.
Figure 4: Binding topologies of the ammonium ion depending on the crown ring size.
Figure 5: A “pseudorotaxane” structure consisting of 24-crown-8 and a secondary ammonium ion (5); R = Ph.
Figure 6: Typical examples of azacrown ethers, cryptands and related aza macrocycles.
Figure 7: Binding of ammonium to azacrown ethers and cryptands [111-113].
Figure 8: A 19-crown-6-ether with decalino blocking groups (11) and a thiazole-dibenzo-18-crown-6-ether (12).
Figure 9: 1,3-Bis(6-oxopyridazin-1-yl)propane derivatives 13 and 14 by Campayo et al.
Figure 10: Fluorescent azacrown-PET-sensors based on coumarin.
Figure 11: Two different pyridino-cryptands (17 and 18) compared to a pyridino-crown (19); chiral ammonium ion...
Figure 12: Pyridino-18-crown-6 ligand (21), a similar acridino-18-crown-6 ligand (22) and a structurally relat...
Figure 13: Ciral pyridine-azacrown ether receptors 24.
Figure 14: Chiral 15-crown-5 receptors 26 and an analogue 18-crown-6 ligand 27 derived from amino alcohols.
Figure 15: C2-symmetric chiral 18-crown-6 amino alcohol derivatives 28 and related macrocycles.
Figure 16: Macrocycles with diamide-diester groups (30).
Figure 17: C2-symmetric chiral aza-18-crown-6 ethers (31) with phenethylamine residues.
Figure 18: Chiral C-pivot p-methoxy-phenoxy-lariat ethers.
Figure 19: Chiral lariat crown ether 34.
Figure 20: Sucrose-based chiral crown ether receptors 36.
Figure 21: Permethylated fructooligosaccharide 37 showing induced-fit chiral recognition.
Figure 22: Biphenanthryl-18-crown-6 derivative 38.
Figure 23: Chiral lariat crown ethers derived from binol by Fuji et al.
Figure 24: Chiral phenolic crown ether 41 with “aryl chiral barriers” and guest amines.
Figure 25: Chiral bis-crown receptor 43 with a meso-ternaphthalene backbone.
Figure 26: Chromogenic pH-dependent bis-crown chemosensor 44 for diamines.
Figure 27: Triamine guests for binding to receptor 44.
Figure 28: Chiral bis-crown phenolphthalein chemosensors 46.
Figure 29: Crown ether amino acid 47.
Figure 30: Luminescent receptor 48 for bis-alkylammonium guests.
Figure 31: Luminescent CEAA (49a), a bis-CEAA receptor for amino acids (49b) and the structure of lysine bindi...
Figure 32: Luminescent CEAA tripeptide for binding small peptides.
Figure 33: Bis crown ether 51a self assembles co-operatively with C60-ammonium ion 51b.
Figure 34: Triptycene-based macrotricyclic dibenzo-[24]-crown-8 ether host 52 and guests.
Figure 35: Copper imido diacetic acid azacrown receptor 53a and the suggested His-Lys binding motif; a copper ...
Figure 36: Urea (54) and thiourea (55) benzo crown receptor for transport and extraction of amino acids.
Figure 37: Crown pyryliums ion receptors 56 for amino acids.
Figure 38: Ditopic sulfonamide bridged crown ether receptor 57.
Figure 39: Luminescent peptide receptor 58.
Figure 40: Luminescent receptor 59 for the detection of D-glucosamine hydrochloride in water/ethanol and lumin...
Figure 41: Guanidinium azacrown receptor 61 for simple amino acids and ditopic receptor 62 with crown ether an...
Figure 42: Chiral bicyclic guanidinium azacrown receptor 63 and similar receptor 64 for the enantioselective t...
Figure 43: Receptors for zwitterionic species based on luminescent CEAAs.
Figure 44: 1,10-Azacrown ethers with sugar podand arms and the anticancer agent busulfan.
Figure 45: Benzo-18-crown-6 modified β-cyclodextrin 69 and β-cyclodextrin functionalized with diaza-18-crown-6...
Figure 46: Receptors for colorimetric detection of primary and secondary ammonium ions.
Figure 47: Porphyrine-crown-receptors 72.
Figure 48: Porphyrin-crown ether conjugate 73 and fullerene-ammonium ion guest 74.
Figure 49: Calix[4]arene (75a), homooxocalix[4]arene (75b) and resorcin[4]arene (75c) compared (R = H, alkyl c...
Figure 50: Calix[4]arene and ammonium ion guest (R = H, alkyl, OAcyl etc.), possible binding sites; A: co-ordi...
Figure 51: Typical guests for studies with calixarenes and related molecules.
Figure 52: Lower rim modified p-tert-butylcalix[5]arenes 82.
Figure 53: The first example of a water soluble calixarene.
Figure 54: Sulfonated water soluble calix[n]arenes that bind ammonium ions.
Figure 55: Displacement assay for acetylcholine (3) with a sulfonato-calix[6]arene (84b).
Figure 56: Amino acid inclusion in p-sulfonatocalix[4]arene (84a).
Figure 57: Calixarene receptor family 86 with upper and lower rim functionalization.
Figure 58: Calix[6]arenes 87 with one carboxylic acid functionality.
Figure 59: Sulfonated calix[n]arenes with mono-substitution at the lower rim systematically studied on their r...
Figure 60: Cyclotetrachromotropylene host (91) and its binding to lysine (81c).
Figure 61: Calixarenes 92 and 93 with phosphonic acids groups.
Figure 62: Calix[4]arene tetraphosphonic acid (94a) and a double bridged analogue (94b).
Figure 63: Calix[4]arene tetraphosphonic acid ester (92c) for surface recognition experiments.
Figure 64: Calixarene receptors 95 with α-aminophosphonate groups.
Figure 65: A bridged homocalix[3]arene 95 and a distally bridged homocalix[4]crown 96.
Figure 66: Homocalix[3]arene ammonium ion receptor 97a and the Reichardt’s dye (97b) for colorimetric assays.
Figure 67: Chromogenic diazo-bridged calix[4]arene 98.
Figure 68: Calixarene receptor 99 by Huang et al.
Figure 69: Calixarenes 100 reported by Parisi et al.
Figure 70: Guest molecules for inclusion in calixarenes 100: DAP × 2 HCl (101a), APA (101b) and Lys-OMe × 2 HC...
Figure 71: Different N-linked peptido-calixarenes open and with glycol chain bridges.
Figure 72: (S)-1,1′-Bi-2-naphthol calixarene derivative 104 published by Kubo et al.
Figure 73: A chiral ammonium-ion receptor 105 based on the calix[4]arene skeleton.
Figure 74: R-/S-phenylalaninol functionalized calix[6]arenes 106a and 106b.
Figure 75: Capped homocalix[3]arene ammonium ion receptor 107.
Figure 76: Two C3 symmetric capped calix[6]arenes 108 and 109.
Figure 77: Phosphorous-containing rigidified calix[6]arene 110.
Figure 78: Calix[6]azacryptand 111.
Figure 79: Further substituted calix[6]azacryptands 112.
Figure 80: Resorcin[4]arene (75c) and the cavitands (113).
Figure 81: Tetrasulfonatomethylcalix[4]resorcinarene (114).
Figure 82: Resorcin[4]arenes (115a/b) and pyrogallo[4]arenes (115c, 116).
Figure 83: Displacement assay for acetylcholine (3) with tetracyanoresorcin[4]arene (117).
Figure 84: Tetramethoxy resorcinarene mono-crown-5 (118).
Figure 85: Components of a resorcinarene based displacement assay for ammonium ions.
Figure 86: Chiral basket resorcin[4]arenas 121.
Figure 87: Resorcinarenes with deeper cavitand structure (122).
Figure 88: Resorcinarene with partially open deeper cavitand structure (123).
Figure 89: Water-stabilized deep cavitands with partially structure (124, 125).
Figure 90: Charged cavitands 126 for tetralkylammonium ions.
Figure 91: Ditopic calix[4]arene receptor 127 capped with glycol chains.
Figure 92: A calix[5]arene dimer for diammonium salt recognition.
Figure 93: Calixarene parts 92c and 129 for the formation molecular capsules.
Figure 94: Encapsulation of a quaternary ammonium cation by two resorcin[4]arene molecules (NMe4+@[75c]2 × Cl−...
Figure 95: Encapsulation of a quaternary ammonium cation by six resorcin[4]arene molecules (NMe3D+@[130]6 × Cl−...
Figure 96: Structure and schematic of cucurbit[6]uril (CB[6], 131a).
Figure 97: Cyclohexanocucurbit[6]uril (CB′[6], 132) and the guest molecule spermine (133).
Figure 98: α,α,δ,δ-Tetramethylcucurbit[6]uril (134).
Figure 99: Structure of the cucurbituril-phthalhydrazide analogue 135.
Figure 100: Organic cavities for the displacement assay for amine differentiation.
Figure 101: Displacement assay methodology for diammonium- and related guests involving cucurbiturils and some ...
Figure 102: Nor-seco-Cucurbituril (±)-bis-ns-CB[6] (140) and guest molecules.
Figure 103: The cucurbit[6]uril based complexes 141 for chiral discrimination.
Figure 104: Cucurbit[7]uril (131c) and its ferrocene guests (142) opposed.
Figure 105: Cucurbit[7]uril (131c) guest inclusion and representative guests.
Figure 106: Cucurbit[7]uril (131c) binding to succinylcholine (145) and different bis-ammonium and bis-phosphon...
Figure 107: Paraquat-cucurbit[8]uril complex 149.
Figure 108: Gluconuril-based ammonium receptors 150.
Figure 109: Examples of clefts (151a), tweezers (151b, 151c, 151d) and clips (151e).
Figure 110: Kemp’s triacid (152a), on example of Rebek’s receptors (152b) and guests.
Figure 111: Amino acid receptor (154) by Rebek et al.
Figure 112: Hexagonal lattice designed hosts by Bell et al.
Figure 113: Bell’s amidinium receptor (156) and the amidinium ion (157).
Figure 114: Aromatic phosphonic acids.
Figure 115: Xylene phosphonates 159 and 160a/b for recognition of amines and amino alcohols.
Figure 116: Bisphosphonate recognition motif 161 for a colorimetric assay with alizarin complexone (163) for ca...
Figure 117: Bisphosphonate/phosphate clip 164 and bisphosphonate cleft 165.
Figure 118: N-Methylpyrazine 166a, N-methylnicotinamide iodide (166b) and NAD+ (166c).
Figure 119: Bisphosphate cavitands.
Figure 120: Bisphosphonate 167 of Schrader and Finocchiaro.
Figure 121: Tweezer 168 for noradrenaline (80b).
Figure 122: Different tripods and heparin (170).
Figure 123: Squaramide based receptors 172.
Figure 124: Cage like NH4+ receptor 173 of Kim et al.
Figure 125: Ammonium receptors 174 of Chin et al.
Figure 126: 2-Oxazolin-based ammonium receptors 175a–d and 176 by Ahn et al.
Figure 127: Racemic guest molecules 177.
Figure 128: Tripods based on a imidazole containing macrocycle (178) and the guest molecules employed in the st...
Figure 129: Ammonium ion receptor 180.
Figure 130: Tetraoxa[3.3.3.3]paracyclophanes 181 and a cyclophanic tetraester (182).
Figure 131: Peptidic bridged paraquat-cyclophane.
Figure 132: Shape-selective noradrenaline host.
Figure 133: Receptor 185 for binding of noradrenaline on surface layers from Schrader et al.
Figure 134: Tetraphosphonate receptor for binding of noradrenaline.
Figure 135: Tetraphosphonate 187 of Schrader and Finocchiaro.
Figure 136: Zinc-Porphyrin ammonium-ion receptors 188 and 189 of Mizutani et al.
Figure 137: Zinc porphyrin receptor 190.
Figure 138: Zinc porphyrin receptors 191 capable of amino acid binding.
Figure 139: Zinc-porphyrins with amino acid side chains for stereoinduction.
Figure 140: Bis-zinc-bis-porphyrin based on Tröger’s base 193.
Figure 141: BINAP-zinc-prophyrin derivative 194 and it’s guests.
Figure 142: Bisaryl-linked-zinc-porphyrin receptors.
Figure 143: Bis-zinc-porphyrin 199 for diamine recognition and guests.
Figure 144: Bis-zinc-porphyrin crown ether 201.
Figure 145: Bis-zinc-porphyrin 202 for stereodiscrimination (L = large substituent; S = small substituent).
Figure 146: Bis-zinc-porphyrin[3]rotaxane and its copper complex and guests.
Figure 147: Dien-bipyridyl ligand 206 for co-ordination of two metal atoms.
Figure 148: The ligand and corresponding tetradentate co-complex 207 serving as enantioselective receptor for a...
Figure 149: Bis(oxazoline)–copper(II) complex 208 for the recognition of amino acids in aqueous solution.
Figure 150: Zinc-salen-complexes 209 for the recognition tertiary amines.
Figure 151: Bis(oxazoline)–copper(II) 211 for the recognition of amino acids in aqueous solution.
Figure 152: Zn(II)-complex of a C2 terpyridine crown ether.
Figure 153: Displacement assay and receptor for aspartate over glutamate.
Figure 154: Chiral complex 214 for a colorimetric displacement assay for amino acids.
Figure 155: Metal complex receptor 215 with tripeptide side arms.
Figure 156: A sandwich complex 216 and its displaceable dye 217.
Figure 157: Lanthanide complexes 218–220 for amino acid recognition.
Figure 158: Nonactin (221), valinomycin (222) and vancomycin (223).
Figure 159: Monesin (224a) and a chiral analogue for enantiodiscrimination of ammonium guests (224b).
Figure 160: Chiral podands (226) compared to pentaglyme-dimethylether (225) and 18-crown-6 (4).
Figure 161: Lasalocid A (228).
Figure 162: Lasalocid derivatives (230) of Sessler et al.
Figure 163: The Coporphyrin I tetraanion (231).
Figure 164: Linear and cyclic peptides for ammonium ion recognition.
Figure 165: Cyclic and bicyclic depsipeptides for ammonium ion recognition.
Figure 166: α-Cyclodextrin (136a) and novocaine (236).
Figure 167: Helical diol receptor 237 by Reetz and Sostmann.
Figure 168: Ammonium binding spherand by Cram et al. (238a) and the cyclic[6]metaphenylacetylene 238b in compar...
Figure 169: Receptor for peptide backbone and ammonium binding (239).
Figure 170: Anion sensor principle with 3-hydroxy-2-naphthanilide of Jiang et al.
Figure 171: 7-bromo-3-hydroxy-N-(2-hydroxyphenyl)naphthalene 2-carboxamide (241) and its amine binding.
Figure 172: Naturally occurring catechins with affinity to quaternary ammonium ions.
Figure 173: Spiropyran (244) and merocyanine form (244a) of the amino acid receptors of Fuji et al.
Figure 174: Coumarin aldehyde (245) and its iminium species with amino acid bound (245a) by Glass et al.
Figure 175: Coumarin aldehyde appended with boronic acid.
Figure 176: Quinolone aldehyde dimers by Glass et al.
Figure 177: Chromogenic ammonium ion receptors with trifluoroacetophenone recognition motifs.
Figure 178: Chromogenic ammonium ion receptor with trifluoroacetophenone recognition motif bound on different m...
Synthesis of lipophilic 1-deoxygalactonojirimycin derivatives as D-galactosidase inhibitors
- Georg Schitter,
- Elisabeth Scheucher,
- Andreas J. Steiner,
- Arnold E. Stütz,
- Martin Thonhofer,
- Chris A. Tarling,
- Stephen G. Withers,
- Jacqueline Wicki,
- Katrin Fantur,
- Eduard Paschke,
- Don J. Mahuran,
- Brigitte A. Rigat,
- Michael Tropak and
- Tanja M. Wrodnigg
Beilstein J. Org. Chem. 2010, 6, No. 21, doi:10.3762/bjoc.6.21
- substituent. For the synthesis of compound 16, 4-isopropylbenzoic acid was reacted with the primary amine under amide coupling conditions with O-(benzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium tetrafluoro-borate (TBTU) as the coupling reagent in DMF and triethylamine. Likewise, nicotinic acid under the same
- )-1-deoxygalactonojirimycin (15) from 12 via 14. Synthesis of lipophilic 1-deoxy-D-galactonojirimycin derivatives 16–18 by chemoselective acylation of 15. Synthesis of compounds 19 as well as 20 from primary amine 15. Synthesis of compound 22. Inhibitory activities of compounds 16–20 and 22 with β
Graphical Abstract
Figure 1: Typical representatives of iminosugars.
Figure 2: N-Modified iminosugars 5–9 as potential pharmacological chaperones.
Figure 3: Structure of NOEV 10.
Scheme 1: Three-step-synthesis of partially protected 1-deoxy-D-galactonojirimycin derivative 12 from 10 via ...
Scheme 2: Synthesis of N-(6-aminohexyl)-1-deoxygalactonojirimycin (15) from 12 via 14.
Scheme 3: Synthesis of lipophilic 1-deoxy-D-galactonojirimycin derivatives 16–18 by chemoselective acylation ...
Scheme 4: Synthesis of compounds 19 as well as 20 from primary amine 15.
Scheme 5: Synthesis of compound 22.
A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis
- Magnus Rueping and
- Boris J. Nachtsheim
Beilstein J. Org. Chem. 2010, 6, No. 6, doi:10.3762/bjoc.6.6
- which provided the products with high enantioselectivities. Beside indoles, anilines have gained much attention as target for hydroarylation reactions. However, the main issues for FC alkylations of anilines are the deactivation of the catalyst due to coordination of the primary amine and/or concurrent
Graphical Abstract
Scheme 1: AlCl3-mediated reaction between amyl chloride and benzene as developed by Friedel and Crafts.
Figure 1: Most often used metal salts for catalytic FC alkylations and hydroarylations of arenes.
Figure 2: 1,1-diarylalkanes with biological activity.
Scheme 2: Alkylating reagents and side products produced.
Scheme 3: Initially reported TeCl4-mediated FC alkylation of 1-penylethanol with toluene.
Scheme 4: Sc(OTf)3-catalyzed FC benzylation of arenes.
Scheme 5: Reductive FC alkylation of arenes with arenecarbaldehydes.
Scheme 6: Iron(III)-catalyzed FC benzylation of arenes and heteroarenes.
Scheme 7: A gold(III)-catalyzed route to beclobrate.
Scheme 8: Catalytic FC-type alkylations of 1,3-dicarbonyl compounds.
Scheme 9: Iron(III)-catalyzed synthesis of phenprocoumon.
Scheme 10: Bi(OTf)3-catalyzed FC alkylation of benzyl alcohols developed by Rueping et al.
Scheme 11: (A) Bi(OTf)3-catalyzed intramolecular FC alkylation as an efficient route to substituted fulvenes. ...
Scheme 12: FC-type glycosylation of 1,2-dimethylindole and trimethoxybenzene.
Scheme 13: FC alkylation with highly reactive ferrocenyl- and benzyl alcohols. The reaction proceeds even with...
Scheme 14: Reductive FC alkylation of arenes with benzaldehyde and acetophenone catalyzed by the Ir-carbene co...
Scheme 15: Formal synthesis of 1,1-diarylalkanes from benzyl alcohols and styrenes.
Scheme 16: (A) Mo-catalyzed hydroarylation of styrenes and cyclohexenes. (B) Hydroalkylation–cyclization casca...
Scheme 17: Bi(III)-catalyzed hydroarylation of styrenes with arenes and heteroarenes.
Scheme 18: BiCl3-catalyzed ene/FC alkylation reaction cascade – A fast access to highly arylated dihydroindene...
Scheme 19: Au(I)/Ag(I)-catalyzed hydroarylation of indoles with styrenes, aliphatic and cyclic alkenes.
Scheme 20: First transition-metal-catalyzed ortho-hydroarylation developed by Beller et al.
Scheme 21: (A) Ti(IV)-mediated rearrangement of an N-benzylated aniline to the corresponding ortho-alkylated a...
Scheme 22: Dibenzylation of aniline gives potentially useful amine-based ligands in a one-step procedure.
Scheme 23: FC-type alkylations with allyl alcohols as alkylating reagents – linear vs. branched product format...
Scheme 24: (A) First catalytic FC allylation and cinnamylation using allyl alcohols and its derivatives. (B) E...
Scheme 25: FC allylation/cyclization reaction yielding substituted chromanes.
Scheme 26: Synthesis of (all-rac)-α-tocopherol utilizing Lewis- and strong Brønsted-acids.
Scheme 27: Au(III)-catalyzed cinnamylation of arenes.
Scheme 28: “Exhaustive” allylation of benzene-1,3,5-triol.
Scheme 29: Palladium-catalyzed allylation of indole.
Scheme 30: Pd-catalyzed synthesis of pyrroloindoles from L-tryptophane.
Scheme 31: Ru(IV)-catalyzed allylation of indole and pyrroles with unique regioselectivity.
Scheme 32: Silver(I)-catalyzed intramolecular FC-type allylation of arenes and heteroarenes.
Scheme 33: FC-type alkylations of arenes using propargyl alcohols.
Scheme 34: (A) Propargylation of arenes with stoichiometric amounts of the Ru-allenylidene complex 86. (B) Fir...
Scheme 35: Diruthenium-catalyzed formation of chromenes and 1H-naphtho[2,1-b]pyrans.
Scheme 36: Rhenium(V)-catalyzed FC propargylations as a first step in the total synthesis of podophyllotoxin, ...
Scheme 37: Scandium-catalyzed arylation of 3-sulfanyl- and 3-selanylpropargyl alcohols.
Scheme 38: Synthesis of 1,3-diarylpropynes via direct coupling of propargyl trichloracetimidates and arenes.
Scheme 39: Diastereoselective substitutions of benzyl alcohols.
Scheme 40: (A) First diastereoselective FC alkylations developed by Bach et al. (B) anti-Selective FC alkylati...
Scheme 41: Diastereoselective AuCl3-catalyzed FC alkylation.
Scheme 42: Bi(OTf)3-catalyzed alkylation of α-chiral benzyl acetates with silyl enol ethers.
Scheme 43: Bi(OTf)3-catalyzed diastereoselective substitution of propargyl acetates.
Scheme 44: Nucelophilic substitution of enantioenriched ferrocenyl alcohols.
Scheme 45: First catalytic enantioselective propargylation of arenes.
Mitomycins syntheses: a recent update
- Jean-Christophe Andrez
Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33
- requisite eight membered ring was formed by the well-established chemistry of quinones using an intramolecular Michael addition by the primary amine 157 (Scheme 44) [118]. The synthesis began with the known phenol 158 which was reacted with allyl bromide to trigger a Claisen rearrangement (Scheme 45). This
- selectively reduced to the corresponding amine with stannous chloride and thiophenol and the aziridine was fashioned by protection of the primary amine followed by an intramolecular Mistunobu reaction. The tetracyclic framework was completed by an intramolecular Michael addition to give desmethoxymitomycin A
Graphical Abstract
Scheme 1: Aziridine containing natural products.
Scheme 2: Mitomycin structures and nomenclature.
Scheme 3: Base catalysed epimerization of mitomycin B.
Scheme 4: Biosynthesis of mitomycin C (MMC) 7.
Scheme 5: Mode of action of mitomycin C.
Scheme 6: The N–C3–C9a disconnection.
Scheme 7: Danishefsky’s Retrosynthesis of mitomycin K.
Scheme 8: Hetero Diels–Alder reaction en route to mitomycins.
Scheme 9: Nitroso Diels–Alder cycloaddition.
Scheme 10: Frank azide cycloadddition.
Scheme 11: Final steps of mitomycin K synthesis. aPDC, DCM; bPhSCH2N3, PhH, 80 °C; cL-selectride, THF, −78 °C; ...
Scheme 12: Naruta–Maruyama retrosynthesis.
Scheme 13: Synthesis of a leucoaziridinomitosane by nitrene cycloaddition. aAlCl3-Et2O; bNaH, ClCH2OMe; cn-BuL...
Scheme 14: Thermal decomposition of azidoquinone 51.
Scheme 15: Diastereoselectivity during the cycloaddition.
Scheme 16: Oxidation with iodo-azide.
Scheme 17: Williams’ approach towards mitomycins.aDEIPSCl, Imidazole, DCM; bPd/C, HCO2NH4, MeOH; cAllocCl, NaH...
Scheme 18: Synthesis of pyrrolidones by homoconjugate addition.
Scheme 19: Homoconjugate addition on the fully functionalized substrate.
Scheme 20: Introduction of the olefin.
Scheme 21: Retrosynthesis of N–C9a, N–C3 bond formation.
Scheme 22: Synthesis of the pyrrolo[1,2]indole 82 using N-PSP activation.aAc2O, Py; bAc2O, Hg(OAc)2, AcOH, 90%...
Scheme 23: Synthesis of an aziridinomitosane. am-CPBA, DCM then iPr2NH, CCl4 reflux; bK2CO3, MeOH; cBnBr, KH; d...
Scheme 24: Oxidation products of a leucoaziridinomitosane obtained from a Polonovski oxidation.
Scheme 25: Polonovski oxidation of an aziridinomitosane. am-CPBA; bPd/C, H2; cDimethoxypropane, PPTS.
Scheme 26: The C1–C9a disconnection.
Scheme 27: Ziegler synthesis of desmethoxymitomycin A.aIm2C=O, THF; bNH3; cTMSOTf, 2,6-di-tert-butylpyridine, ...
Scheme 28: Transformation of sodium erythorbate.aTBDMSCl; bNaN3; cPPh3; d(Boc)2O, DMAP; eTBAF; fTf2O, Pyr.
Scheme 29: Formation of C9,C10-unsaturation in the mitomycins. am-CPBA, DCM; bO3, MeOH; cMe2S; dKHMDS, (EtO)3P...
Scheme 30: Fragmentation mechanism.
Scheme 31: Michael addition-cyclisation.
Scheme 32: SmI2 8-endo-dig cyclisation.
Scheme 33: Synthesis of pyrrolo[1,2-a]indole by 5-exo-dig radical cyclization.
Scheme 34: The C9–C9a disconnection.
Scheme 35: Intramolecular nitrile oxide cycloaddition.
Scheme 36: Regioselectivity of the INOC.
Scheme 37: Fukuyama’s INOC strategy.
Scheme 38: Synthesis of a mitosane core by rearrangement of a 1-(1-pyrrolidinyl)-1,3-butadiene.
Scheme 39: Sulikowski synthesis of an aziridinomitosene. aPd(Tol3P)2Cl2, Bu3SnF, 140; bH2, Pd/C; cTFAA, Et3N; d...
Scheme 40: Enantioselective carbene insertion.
Scheme 41: Parson’s radical cyclization.
Scheme 42: Cha’s mitomycin B core synthesis.
Scheme 43: The N-aromatic disconnection.
Scheme 44: Kishi retrosynthesis.
Scheme 45: Kishi synthesis of a starting material. aallyl bromide, K2CO3, acetone, reflux; bN,N-Dimethylanilin...
Scheme 46: Kishi synthesis of MMC 7. aLDA, THF, −78 °C then PhSeBr, THF, −78 °C; bH2O2, THF-EtOAc; cDIBAL, DCM...
Scheme 47: Acid catalyzed degradation of MMC 7.
Scheme 48: In vivo formation of apomitomycin B.
Scheme 49: Advanced intermediate for apomitomycin B synthesis.
Scheme 50: Remers synthesis of a functionalized mitosene. aTMSCl, Et3N, ZnCl2 then NBS; bAcOK; cNH2OH; dPd/C, H...
Scheme 51: Coleman synthesis of desmethoxymitomycin A. aSnCl2, PhSH, Et3N, CH3CN; bClCO2Bn, Et3N; cPPh3, DIAD,...
Scheme 52: Transition state and pyrrolidine synthesis.
Scheme 53: Air oxidation of mitosanes and aziridinomitosanes.
Scheme 54: The C9-aromatic disconnection.
Scheme 55: Synthesis of the aziridine precursor. aLHMDS, THF; bNaOH; c(s)-α-Me-BnNH2, DCC, HOBT; dDIBAL; eK2CO3...
Scheme 56: Synthesis of 206 via enamine conjugate addition.
Scheme 57: Rapoport synthesis of an aziridinomitosene.
Scheme 58: One pot synthesis of a mitomycin analog.
Scheme 59: Synthesis of compound 218 via intramolecular Heck coupling. aEtMgCl, THF, then 220; bMsCl, Et3N; cN...
Scheme 60: Elaboration of indole 223. aEt3N, Ac2O; bAcOH; cSOCl2, Et3N; dNaN3, DMF; eH2SO4, THF; fK2CO3, MeOH; ...
Scheme 61: C9-C9a functionalization from indole.
Scheme 62: Synthesis of mitomycin K. a2 equiv. MoO5.HMPA, MeOH; bPPh3, Et3N, THF-H2O; cMeOTf, Py, DCM; dMe3SiCH...
Scheme 63: Configurational stability of mitomycin K derivatives.
Scheme 64: Epimerization of carbon C9a in compound 227b.
Scheme 65: Corey–Chaykovsky synthesis of indol 235.
Scheme 66: Cory intramolecular aza-Darzens reaction for the formation of aziridinomitosene 239.
Scheme 67: Jimenez synthesis of aziridinomitosene 242.
Scheme 68: Von Braun opening of indoline 244.
Scheme 69: C9a oxidation of an aziridinomitosane with DDQ/OsO4.
Scheme 70: Synthesis of epi-mitomycin K. aNaH, Me2SO4; bH2, Pd/C; cMitscher reagent [165]; d[(trimethylsilyl)methyl...
Scheme 71: Mitomycins rearrangement.
Scheme 72: Fukuyama’s retrosynthesis.
Scheme 73: [2+3] Cycloaddition en route to isomitomycin A. aToluene, 110 °C; bDIBAL, THF, −78 °C; cAc2O, Py.; d...
Scheme 74: Final steps of Fukuyama’s synthesis.
Scheme 75: “Crisscross annulation”.
Scheme 76: Synthesis of 274; the 8-membered ring 274 was made using a crisscross annulation. a20% Pd(OH)2/C, H2...
Scheme 77: Conformational analysis of compound 273 and 275.
Scheme 78: Synthesis of a mitomycin analog. aNa2S2O4, H2O, DCM; bBnBr (10 equiv), K2CO3, 18-crown-6 (cat.), TH...
Scheme 79: Vedejs retrosynthesis.
Scheme 80: Formation of the azomethine ylide.
Scheme 81: Vedejs second synthesis of an aziridinomitosene. aDIBAL; bTPAP, NMO; c287; dTBSCl, imidazole.
Scheme 82: Trityl deprotection and new aziridine protecting group 300.
Scheme 83: Ene reaction towards benzazocinones.
Scheme 84: Benzazocenols via homo-Brook rearrangement.
Scheme 85: Pt-catalyzed [3+2] cycloaddition.
Scheme 86: Carbonylative lactamization entry to benzazocenols. aZn(OTf)2, (+)-N-methylephedrine, Et3N, TMS-ace...
Scheme 87: 8 membered ring formation by RCM. aBOC2O, NaHCO3; bTBSCl, Imidazole, DMF; callyl bromide, NaH, DMF; ...
Scheme 88: Aziridinomitosene synthesis. aTMSN3; bTFA; cPOCl3, DMF; dNaClO2, NaH2PO4, 2-methyl-2-butene; eMeI, ...
Scheme 89: Metathesis from an indole.
Scheme 90: Synthesis of early biosynthetic intermediates of mitomycins.
N-acylation of ethanolamine using lipase: a chemoselective catalyst
- Mazaahir Kidwai,
- Roona Poddar and
- Poonam Mothsra
Beilstein J. Org. Chem. 2009, 5, No. 10, doi:10.3762/bjoc.5.10
- ) the high reactivity of primary amine, (ii) the fact that use of excess fatty acid or ester 1a–h is not required to convert virtually all the amine to its ion-pair form and (iii) in aminoalkanols NH2(CH2)nOH, where n < 3, there is migration of acyl groups from O→N spontaneously when excess of fatty
Graphical Abstract
Scheme 1: 1a n = 8 R1 = H; 1b n = 10 R1 = H; 1c n = 12 R1 = H; 1d n = 14 R1 = H; 1e n = 8 R1 = C2H5; 1f n = 1...
Figure 1: Effect of different methods using 20 mg of enzyme at 60 °C; Method A: conventional method, Method B...
Figure 2: Effect of the temperature using equimolar ratio and 20 mg of enzyme.
A facile synthesis and fungicidal activities of 2-(alkylamino)-5,6-dimethylthieno[2,3-d]pyrimidin- 4(3H)-ones
- Yang-Gen Hu,
- Ai-Hua Zheng,
- Xu-Zhi Ruan and
- Ming-Wu Ding
Beilstein J. Org. Chem. 2008, 4, No. 49, doi:10.3762/bjoc.4.49
- ]pyrimidin-4(3H)-ones 6 in satisfactory yields at room temperature (Scheme 2). The results are listed in Table 1. The reaction of carbodiimides 4 with primary amine RNH2 in the presence of EtONa provided only 2-(alkylamino)-5,6-dimethylthieno[2,3-d]pyrimidin-4(3H)-ones 8 (Scheme 3), one of the possible
- ml) was added the primary amine (2 mmol). After the reaction mixture was stirred for 5–6 h, the solvent was removed and anhydrous ethanol (10 ml) with several drops of EtONa in EtOH were added. The mixture was stirred for 6–12 h at room temperature. The solution was condensed and the residue was
Graphical Abstract
Scheme 1: Preparation of iminophosphorane 3.
Scheme 2: Preparation of 2-(dialkylamino)-5,6-dimethylthieno[2,3-d]pyrimidin-4(3H)-ones 6.
Scheme 3: Preparation of 2-alkylamino-5,6-dimethylthieno[2,3-d]pyrimidin-4(3H)-ones 8.
The role of an aromatic group in remote chiral induction during conjugate addition of α-sulfonylallylic carbanions to ethyl crotonate
- Shlomo Levinger,
- Ranjeet Nair and
- Alfred Hassner
Beilstein J. Org. Chem. 2008, 4, No. 32, doi:10.3762/bjoc.4.32
- cyanoborohydride in an acidic medium. Phenyl-, (4-nitrophenyl)- and (1-naphthyl)ethylamines 6a, c, e are commercial. Interestingly, the 9-anthryl nucleus in both primary amine 6h and its allyl sulfone congener 1h shows a peculiar 1H NMR spectrum: a broad signal representing both protons 1 and 8 in the first
Graphical Abstract
Scheme 1: Transmission of asymmetry in the conjugate addition of allyl sulfones to ethyl crotonate depending ...
Scheme 2: Preparation of donor precursors for conjugate addition (1), bearing a remote stereogenic center.
Scheme 3: Borch reductive amination of acetophenones.
Scheme 4: Preparation of [(9-anthryl)alkyl]- and (mesitylalkyl)amines 6h and 6j from nitriles via imines 8.
Figure 1: Calculated minimum energy conformation of lithiated amino-substituted sulfone 1a showing π-interact...
Perhalogenated pyrimidine scaffolds. Reactions of 5-chloro- 2,4,6-trifluoropyrimidine with nitrogen centred nucleophiles
- Emma L. Parks,
- Graham Sandford,
- John A. Christopher and
- David D. Miller
Beilstein J. Org. Chem. 2008, 4, No. 22, doi:10.3762/bjoc.4.22
- 2,4,6-trifluoropyrimidine with ammonia is reported [20] to give two products in a 4 : 1 ratio and a primary amine, ethanolamine, gave a 2 : 1 ratio of products. Therefore, reactions of 1 with nitrogen centred nucleophiles are more selective than 2,4,6-trifluoropyrimidine despite the increased steric
Graphical Abstract
Figure 1: Pharmaceuticals with pyrimidine sub-units.
Scheme 1: Use of 2,4,6-trichloropyrimidine as a core scaffold. Reagents and Conditions: a) bis(4-methoxybenzy...
Scheme 2: Reaction of 1 with benzamidine.
Figure 2: Molecular structure of 3g.
New acylides: synthesis of 3-O-[γ-(4-oxo-2-aryl- thiazolidin- 3-yl)butyryl]erythromycin A derivatives
- Deepa Pandey,
- Wahajul Haq and
- Seturam B. Katti
Beilstein J. Org. Chem. 2008, 4, No. 14, doi:10.3762/bjoc.4.14
- -thiazolidin-3-yl)butyryl]erythromycin A derivatives have been synthesized. The 3-hydroxy group was derivatised to a primary amine and subsequently the thiazolidinone nucleus was generated at the amino functionality through DCC mediated one-pot three-component reaction in good yields. Background Second
Graphical Abstract
Figure 1: Second generation macrolides.
Figure 2: Ketolides and acylides.
Scheme 1: Synthesis of 3-O-[γ-(4-oxo-2-aryl-thiazolidin-3-yl)butyryl]-6-O-methylerythromycin A derivatives 4a–...
Scheme 2: Synthesis of 3-O-[γ-(4-oxo-2-aryl-thiazolidin-3-yl)butyryl]erythromycin A derivatives 4a–f (Method ...
Analogues of amphibian alkaloids: total synthesis of (5R,8S,8aS)-(−)-8-methyl- 5-pentyloctahydroindolizine (8-epi-indolizidine 209B) and [(1S,4R,9aS)-(−)-4-pentyloctahydro- 2H-quinolizin- 1-yl]methanol
- Joseph P. Michael,
- Claudia Accone,
- Charles B. de Koning and
- Christiaan W. van der Westhuyzen
Beilstein J. Org. Chem. 2008, 4, No. 5, doi:10.1186/1860-5397-4-5
- -benzyl-1-phenylethylamine, was converted into the primary amine (−)-15 and thence in several steps into the thiolactam (+)-16. Eschenmoser sulfide contraction [22][23] with ethyl bromoacetate yielded the key enaminone intermediate (+)-17, chemoselective reduction of the saturated ester of which produced
Graphical Abstract
Figure 1: Representative quinolizidine alkaloids from amphibians.
Figure 2: Indolizidines and quinolizidines prepared from enaminone precursors 5 and 6. The conventional numbe...
Scheme 1: Reagents: (i) H2 (7 atm), 10% Pd/C, AcOH, rt; (ii) Cl(CH2)3COCl, NaHCO3, CHCl3, reflux; (iii) KOBut...
Scheme 2: Reagents: (i) LiAlH4, THF, 0 °C to rt; (ii) MeSO2Cl, NEt3, CH2Cl2, 0 °C to rt; (iii) Raney Ni, EtOH...
Scheme 3: Reagents: (i) Br(CH2)4COCl, NaHCO3, ClCH2CH2Cl, rt; (ii) NaH, Bu4NI, DMF, rt; (iii) Lawesson's reag...
Scheme 4: Reagents: (i) LiAlH4, Et2O, 0 °C, then add (+)-2 in Et2O, rt; (ii) TBDMSCl, imidazole, DMF, rt; (ii...
Scheme 5: Reagents: (i) aq. HF (40%), MeOH, rt; (ii) Ac2O, pyridine, 0 °C to rt; (iii) Lawesson's reagent, Ph...
Variations in product in reactions of naphthoquinone with primary amines
- Marjit W. Singh,
- Anirban Karmakar,
- Nilotpal Barooah and
- Jubaraj B. Baruah
Beilstein J. Org. Chem. 2007, 3, No. 10, doi:10.1186/1860-5397-3-10
- the literature that the reaction of N-phenyliminophosphorane with 1,2-naphthoquinone results in the formation of 2-anilino-naphthoquinone-1,4-anil [14] and in our present investigation we have observed that such products can be prepared just by reaction of 1,2-naphthoquinone with a primary amine
- rings are perpendicular to each other. The C-S bond formation reaction can be extended to other thiols such as thiophenol and 4-methoxythiophenol, 4-bromothiophenol etc. with 1,4-naphthoquinone as well as 1,4-benzoquinone. The difference in the case of reaction of 1,4-benzoquinone with primary amine
Graphical Abstract
Scheme 1: Reaction of 1,2-naphthoquinone with primary amines.
Figure 1: The solid state structure of (a) 1 and (b) 2 (drawn with 20% thermal ellipsoids).
Scheme 2: Equivalence of reactivity between 1,2 and 1,4-naphthoquinone.
Scheme 3: The reaction of picolylamine with 1,4-naphthoquinone.
Figure 2: (a) The crystal structure of 3 and (b) weak interactions in 3 leading to self-assembly, (c) Structu...
Scheme 4: The reaction of 1,4-naphthoquinone with 4-aminothiophenol and 4-aminophenol.
Figure 3: The 1HNMR spectra (400 MHz) of the reaction mixture of 1,4-naphthoquinone with 4-amino thiophenol (...
Figure 4: The structure of the products from the reaction of 1,4-naphthoquinone with (a) 4-aminothiophenol (b...
Synthesis of coumarin or ferrocene labeled nucleosides via Staudinger ligation
- Ivana Kosiova,
- Andrea Janicova and
- Pavol Kois
Beilstein J. Org. Chem. 2006, 2, No. 23, doi:10.1186/1860-5397-2-23
- primary amine and triarylphosphine oxide. This Staudinger reduction is a frequently used method for the smooth reduction of azides to amines. Iminophosphoranes can react with almost any kind of electrophilic reagent, [15][16] e.g. aldehydes or ketones to form imines. Also less reactive carbonyl
Graphical Abstract
Figure 1: Compounds used for nucleoside labeling.
Scheme 1: Preparation of coumarin labeled nucleosides, (i) PPh3, acetonitrile, (ii) HOBT, DCC, dioxane
Figure 2: Coumarin labeled nucleosides prepared by intermolecular Staudinger ligation.
Scheme 2: Hydrolysis of proposed intermediates I(a-c)-IV(a-c)
Scheme 3: Preparation of ferrocene labeled uridine
Synthesis and glycosidase inhibitory activity of new hexa- substituted C8-glycomimetics
- Olivia Andriuzzi,
- Christine Gravier-Pelletier,
- Gildas Bertho,
- Thierry Prangé and
- Yves Le Merrer
Beilstein J. Org. Chem. 2005, 1, No. 12, doi:10.1186/1860-5397-1-12
- aminocyclitols it could be an epoxidation followed by the nucleophilic opening of the epoxide moiety by a primary amine or another nitrogen nucleophile. Accordingly (Scheme 1), treatment of the fully O-protected L-ido-cyclooctene 1 with a 5 mol% aqueous solution of osmium(IV) tetroxide [34] in acetone in the
- , which crystallizes as a dimer, constituted by a tricyclic system [5-8-5] adopts a more flexible boat-chair conformation, thus allowing its opening by a linear nucleophile (azide anion), but not by a more hindered nucleophile (primary amine). With the key enantiomerically pure azido-alcohol 11 and 12 in
Graphical Abstract
Figure 1: Sugars, iminosugars and carbasugars.
Figure 2: Retrosynthetic analysis.
Scheme 1: Reagents and conditions: (a) OsO4, NMO, tBuOH, rt; (b) TFA, H2O, rt.
Scheme 2: Reagents and conditions: (a) mCPBA, CH2Cl2, NaHCO3, rt; (b) see text.
Scheme 3: Reagents and conditions: (a) i : SOCl2, Et3N, CH2Cl2, 0°C; ii : RuCl3, NaIO4, CCl4, CH3CN, 0°C to r...
Figure 3: 1D proton NMR spectra of the C8 ring in compound 11 (upper) and the simulated signals (down) on the...
Figure 4: Schematic representation of the NOEs (indicated with arrows) found to deduce the structure of 11. B...
Figure 5: X-ray structure of epoxide 7 (upper) and sulfate 9 (down) solved using SHELXS and anisotropically r...
