Search for "triazole" in Full Text gives 290 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Beilstein J. Org. Chem. 2022, 18, 1636–1641, doi:10.3762/bjoc.18.175
Graphical Abstract
Figure 1: (a) Previously developed three-component approach to 1,5-disubstituted 1,2,3-triazoles; (b) double ...
Scheme 1: Results of a trial reaction between 1, o-azidobenzaldehyde (3a) and propargylamine.
Figure 2: Diversely bioactive compounds based on scaffolds A and B.
Scheme 2: Three-component reaction of 1, propargylamine and various o-azidobenzaldehydes.
Figure 3: Aromatic azido aldehydes 3j–l that failed to react with 1 and propargylamine.
Scheme 3: Variations of the amine component in the reactions with 1 and 3a.
Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170
Graphical Abstract
Scheme 1: The synthesis of 6A-azido-6A-deoxy-per-6-O-tert-butyldimethylsilyl-β-cyclodextrin.
Scheme 2: The synthesis of β-cyclodextrin dimers with permethylated secondary rims.
Scheme 3: The synthesis of β-cyclodextrin dimers with permethylated primary rims.
Figure 1: The fragments of 1H NOESY NMR spectra of 4 (a), 10 (b), and 9 (c) indicating the interaction betwee...
Figure 2: The fragment of the 1H NMR spectrum of compounds 9 (green); 10 (red); 12 (blue) representing the si...
Figure 3: Other cyclodextrins that were used in the solubilization experiments with tetracene.
Figure 4: The tetracene UV absorbance dependence on concentration at 476 nm.
Figure 5: The relative concentrations of tetracene in DMSO solutions with hosts 4, 5, 10, 12, 13–18 referred ...
Figure 6: "Tail-to-tail" (a) and "head-to-head" (b) orientation of two cyclodextrin moieties and primary-rim ...
Figure 7: Isotherms of the titration of tetracene with "dimeric" CD solutions in DMSO at 298 K (circles – 10;...
Figure 8: Isotherms of the titration of tetracene with "monomeric" CD solutions in DMSO at 298 K (circles – 16...
Beilstein J. Org. Chem. 2022, 18, 1524–1531, doi:10.3762/bjoc.18.161
Graphical Abstract
Figure 1: Structures of RBV, betulinic acid (1), and ursolic acid (2).
Scheme 1: Synthesis of 1-azido-3-nitrobenzene (c).
Scheme 2: Synthesis of the triazole-substituted triterpene derivatives 7 and 8.
Figure 2: (A) Activity of compound 8 in A549 cells infected with RSV. MTT assay 96 h after treatment. DMSO (0...
Figure 3: Superposition of the top-ranked docking solution of compound 8 (carbon atoms in yellow, in stick re...
Beilstein J. Org. Chem. 2022, 18, 1088–1099, doi:10.3762/bjoc.18.111
Graphical Abstract
Scheme 1: Reactions of tetrazoloquinoxalines 1 to 1,2,3-triazoloquinoxalines 3 via CuAAC and denitrogenative ...
Scheme 2: Synthesis of tetrazolo[1,5-a]quinoxalines. Reaction conditions: (a) 9, THF or 4 M HCl, 70–110 °C, 2...
Scheme 3: Synthesis of 1,2,3-triazole-substituted quinoxalines via CuAAC from tetrazolo[1,5-a]quinoxaline (11a...
Scheme 4: Mechanism of CuAAC vs denitrogenative annulation.
Scheme 5: Synthesis of bis(tetrazolo)[1,5-a:5',1'-c]quinoxaline (24) and conversion to triazoloimidazoquinoxa...
Scheme 6: Synthesis of rhenium tricarbonyl complexes 27a–d and ORTEP diagrams of the resulting molecular stru...
Scheme 7: Synthesis of rhenium tricarbonyl complex 29 and ORTEP diagram of the resulting molecular structure ...
Scheme 8: Synthesis of a TIQ rhenium complex and ORTEP diagram of the obtained product 30 with the thermal el...
Figure 1: UV–vis absorption spectra of the obtained metal complexes (18 µM solutions) in acetonitrile at 20 °...
Figure 2: Cyclic voltammetry traces for rhenium complexes 27a–d, 29 and 30: 0.5 mM in MeCN solution with 0.1 ...
Beilstein J. Org. Chem. 2022, 18, 1026–1031, doi:10.3762/bjoc.18.103
Graphical Abstract
Scheme 1: From vinyl acetates to α-azidoketones.
Scheme 2: Substrate scope. Reaction conditions: α-arylvinyl acetate (0.5 mmol), TMSN3 (1.0 mmol), n-Bu4NPF6 (...
Scheme 3: Derivatization of α-azidoketone 2.
Scheme 4: Proposed mechanism.
Beilstein J. Org. Chem. 2022, 18, 863–871, doi:10.3762/bjoc.18.87
Graphical Abstract
Figure 1: Biologically active selenides having alkynyl or imidazopyridinyl groups.
Figure 2: (a) ORTEP drawing of 4aa and (b) its stacking structure.
Scheme 1: Control reactions.
Figure 3: Proposed mechanism.
Scheme 2: Transformation from 4aa.
Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62
Graphical Abstract
Figure 1: Butterfly 1 (Figure was reprinted with permission from [45]. Copyright 2012 American Chemical Society. ...
Figure 2: Synthesis of the three-component heteroleptic molecular boat 8 and its use as a catalyst for the Kn...
Figure 3: Synthesis of the two-component triangle 14 and three-component heteroleptic prism 15 [59]. Figure was a...
Figure 4: Catalytic Michael addition reaction using the urea-decorated molecular prism 15 [59].
Figure 5: Self-assembly of two-component tetragonal prismatic architectures with different cavity size. Figur...
Figure 6: Construction of artificial LHS using rhodamine B as an acceptor and 24b as donor generating a photo...
Figure 7: Synthesis of supramolecular spheres with varying [AuCl] concentration inside the cavity. Figure was...
Figure 8: Hydroalkoxylation reaction of γ-allenol 34 in the presence of [AuCl]-encapsulated molecular spheres ...
Figure 9: Two-component heteroleptic triangles of different size containing a BINOL functionality. Figure was...
Figure 10: Asymmetric conjugate addition of chalcone 42 with trans-styrylboronic acid (43) catalyzed by BINOL-...
Figure 11: Encapsulation of monophosphoramidite-Rh(I) catalyst into a heteroleptic tetragonal prismatic cage 47...
Figure 12: (a) Representations of the basic HETPYP, HETPHEN, and HETTAP complex motifs. (b) The three-componen...
Figure 13: Two representative four-component rotors, with a (top) two-arm stator and (bottom) a four-arm stato...
Figure 14: Four-component rotors with a monohead rotator. Figure was adapted with permission from [94]. Copyright ...
Figure 15: (left) Click reaction catalyzed by rotors [Cu2(55)(60)(X)]2+. (right) Yield as a function of the ro...
Figure 16: A supramolecular AND gate. a) In truth table state (0,0) two nanoswitches serve as the receptor ens...
Figure 17: Two supramolecular double rotors (each has two rotational axes) and reference complex [Cu(78)]+ for...
Figure 18: The slider-on-deck system (82•X) (X = 83, 84, or 85). Figure is from [98] and was reprinted from the jo...
Figure 19: Catalysis of a conjugated addition reaction in the presence of the slider-on-deck system (82•X) (X ...
Figure 20: A rotating catalyst builds a catalytic machinery. For catalysis of the catalytic machinery, see Figure 21. F...
Figure 21: Catalytic machinery. Figure was adapted from [100] (“Evolution of catalytic machinery: three-component n...
Figure 22: An information system based on (re)shuffling components between supramolecular structures [99]. Figure ...
Figure 23: Switching between dimeric heteroleptic and homoleptic complex for OFF/ON catalytic formation of rot...
Figure 24: A chemically fueled catalytic system [112]. Figure was adapted from [112]. Copyright 2021 American Chemical S...
Figure 25: (Top) Operation of a fuel acid. (Bottom) Knoevenagel addition [112].
Figure 26: Development of the yield of Knoevenagel product 118 in a fueled system [112]. Figure was reprinted with ...
Figure 27: Weak-link strategy to increased catalytic activity in epoxide opening [119]. Figure was adapted from [24]. C...
Figure 28: A ON/OFF polymerization switch based on the weak-link approach [118]. Figure was reprinted with permissi...
Figure 29: A weak-link switch turning ON/OFF a Diels–Alder reaction [132]. Figure was reprinted with permission fro...
Figure 30: A catalyst duo allowing selective activation of one of two catalytic acylation reactions [133] upon subs...
Figure 31: A four-state switchable nanoswitch (redrawn from [134]).
Figure 32: Sequential catalysis as regulated by nanoswitch 138 and catalyst 139 in the presence of metal ions ...
Figure 33: Remote control of ON/OFF catalysis administrated by two nanoswitches through ion signaling (redrawn...
Beilstein J. Org. Chem. 2022, 18, 539–548, doi:10.3762/bjoc.18.56
Graphical Abstract
Scheme 1: (a) Synthesis route to TBTQ-CB6. Conditions: (i) ethyl azidoacetate, CuSO4, sodium ascorbate, THF/H2...
Figure 1: (a) 1H NMR spectra (400 MHz, D2O, 25 °C) of (1) MV, (2) TBTQ-CB6 and MV, (3) TBTQ-CB6 with [TBTQ-CB6...
Figure 2: (a) 1H NMR spectra (400 MHz, D2O, 25 °C) of (1) DOX, (2) TBTQ-CB6 and DOX, (3) TBTQ-CB6 with [TBTQ-...
Figure 3: (a) 1H NMR spectra (400 MHz, D2O, 25 °C) and (b) partial magnified 1H NMR spectra of (1) SM, (2) TB...
Figure 4: (a) Fluorescence spectra of the mixture of TBTQ-CB6 and SM in different molar ratios at a constant ...
Figure 5: 1H NMR spectra (400 MHz, D2O, 25 °C) of (1) MV (3 mM), (2) TBTQ-CB6 and MV (3 mM each), (3–9) TBTQ-...
Figure 6: 1H NMR spectra (400 MHz, D2O, 25 °C) of (1) DOX (3 mM), (2) TBTQ-CB6 and DOX (3 mM each), (3–9) TBT...
Beilstein J. Org. Chem. 2022, 18, 524–532, doi:10.3762/bjoc.18.54
Graphical Abstract
Figure 1: The structures of chloroquine, hydroxychloroquine, and amodiaquine.
Scheme 1: Synthesis of 3-azolylpyrazoles 3a–c.
Scheme 2: Assumed mechanism for the formation of 1H-pyrazoles 3a–c.
Scheme 3: Synthesis of 3-aminopyrazoles 5b–k and 5-aminopyrazoles 5a and 5l–o.
Scheme 4: Orientation of nucleophilic attack of 7-chloro-4-hydrazinylquinoline on nitrobutadienes 4.
Scheme 5: Synthesis of oxazolidine 6 and pyrazole 7.
Scheme 6: A plausible mechanism for the formation of pyrazole 7.
Scheme 7: Synthesis of pyrazoles 9 and sulfoxide 10d.
Scheme 8: Synthesis of pyrazole 11.
Beilstein J. Org. Chem. 2022, 18, 508–523, doi:10.3762/bjoc.18.53
Graphical Abstract
Figure 1: Molecular structures of (R)-BINOL (left) and (S)-BINOL (right).
Figure 2: Synthesis of Sauvage´s [2]catenanes (S,S)-5 and (S,S)-6 containing two BINOL units by the passive m...
Figure 3: Synthesis of Saito´s [2]rotaxane (R)-10 from a BINOL-based macrocycle by the active metal template ...
Figure 4: Synthesis of Stoddart´s [2]rotaxane (rac)-14 by an ammonium crown ether template.
Figure 5: Synthesis of Stoddart´s BINOL-containing [2]catenanes 18/20/22/24 by π–π recognition.
Figure 6: Synthesis of Takata´s rotaxanes featuring chiral centers on the axle: a) rotaxane (R,R,R/S)-27 obta...
Figure 7: Takata´s chiral polyacetylenes 32/33 featuring BINOL-based [2]rotaxane side chains.
Figure 8: Synthesis of Takata´s chiral thiazolium [2]rotaxanes (R)-35a/b and (R)-38.
Figure 9: Results for the asymmetric benzoin condensation of benzaldehyde (39) with catalysts (R)-35a/b and (R...
Figure 10: Synthesis of Takata´s pyridine-based [2]rotaxane (R)-42.
Figure 11: The asymmetric desymmetrization reaction of meso-1,2-diols with rotaxane (R)-42.
Figure 12: Synthesis of Niemeyer´s axially chiral [2]catenane (S,S)-47.
Figure 13: Results for the enantioselective transfer hydrogenation of 2-phenylquinoline with catalysts (S,S)-47...
Figure 14: Synthesis of Niemeyer´s chiral [2]rotaxanes (S)-56/57.
Figure 15: Results for the enantioselective Michael addition with different rotaxane catalysts (S)-56a/56b/57a/...
Figure 16: Synthesis of Beer´s [2]rotaxanes 64a/b for anion recognition.
Figure 17: Association constants of different anions (used as the Bu4N+ salts) to the [2]rotaxanes (S)-64a/b a...
Figure 18: Synthesis of Beer´s [3]rotaxane (S)-68.
Figure 19: Association constants of different anions (used as the Bu4N+-salts) to the [2]rotaxane (S)-68 and a...
Beilstein J. Org. Chem. 2022, 18, 243–250, doi:10.3762/bjoc.18.29
Graphical Abstract
Scheme 1: Chemical structures of [1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine (a), [1,2,4]triazolo[1,5-b][1,2,4,5...
Scheme 2: Synthesis of [1,2,4]triazolo[1,5-b][1,2,4,5]tetrazines 3a–k.
Figure 1: X-ray structure of N-(6-(4-bromo-3,5-dimethylpyrazol-1-yl)-1,2,4,5-tetrazin-3-yl)benzamide.
Scheme 3: Reactions of triazolo[1,5-b][1,2,4,5]tetrazines 3a,j with N- and O-nucleophiles.
Scheme 4: Reactions of triazolo[1,5-b][1,2,4,5]tetrazines 3a,j with C-nucleophiles.
Scheme 5: Reactions of 6-(3,5-dimethyl-1H-pyrazol-1-yl)-3-methyl-[1,2,4]triazolo[4,3-b][1,2,4,5]tetrazine (10a...
Beilstein J. Org. Chem. 2022, 18, 208–216, doi:10.3762/bjoc.18.24
Graphical Abstract
Figure 1: Chemical structures and reported activities of viral (A), human neuraminidases (B) and Trypanosoma ...
Figure 2: Design and synthesis of potential neuraminidase and trans-sialidase inhibitors exploiting a moiety ...
Figure 3: TcTS and neuraminidase hydrolase activity (A) as well as TcTS transferase activity (B) in the prese...
Figure 4: TcTS and neuraminidase inhibition by 1,2,3-triazole-linked sialic acid derivatives 3a–h (1 mM) usin...
Figure 5: Crystal structure of TcTS (PDB code 1MS1 – coloured red) (A) and neuraminidase (PDB code 2VK6 – col...
Beilstein J. Org. Chem. 2022, 18, 1–12, doi:10.3762/bjoc.18.1
Graphical Abstract
Scheme 1: Synthesis of SMC stapled axin CBD peptides. Reaction conditions: (a) Pd2(dba)3, sSPhos, KF, DME/EtO...
Scheme 2: Overview of the different cross-linkages obtained by intramolecular SMC. A) General structure of SM...
Figure 1: Analysis of the secondary structure by circular dichroism: CD spectra of both isomers of stapled pe...
Figure 2: In vitro binding affinities to β-catenin determined by competitive fluorescence polarisation assays....
Figure 3: Cleavage sites of Proteinase K digestion indicated by a red arrow.
Figure 4: Principal component analysis (PCA) of the macrocycle’s non-hydrogen atoms in the two isomers of P5....
Figure 5: Molecular modelling of the conformational preferences of the SMC stapled peptides P5 (with cis or t...
Beilstein J. Org. Chem. 2021, 17, 2477–2487, doi:10.3762/bjoc.17.164
Graphical Abstract
Figure 1: Structures of azide and alkyne functional molecules and polymers used in the photoinduced CuAAC rea...
Figure 2: UV–vis spectra of CuICl, CuIICl2 and BPNs.
Figure 3: a) 1H NMR spectra of the model reaction between benzyl azide (Az-1) and phenylacetylene (Alk-3) bef...
Scheme 1: Proposed mechanism for photoinduced CuAAC reaction using exfoliated BPNs.
Figure 4: a) 1H NMR spectrum of chain end modified PCL-Anth; b) UV–vis spectra of (azidomethyl)anthracene (bl...
Scheme 2: Synthesis of PS-b-PCL block copolymer via exfoliated BPNs-mediated photoinduced CuAAC reaction.
Figure 5: a) GPC traces of PS-Az, PCL-Alk and block copolymer (Ps-b-PCL) b) 1H NMR spectrum of the block copo...
Scheme 3: Preparation of the cross-linked polymer by CuAAC reaction using multifunctional monomers, Az-3 and ...
Figure 6: a) DSC thermogram of photoinduced synthesis of nanocomposite networks (heating rate: 10 °C/min). b)...
Figure 7: (a, b) TEM images of cross-linked polymer at two different magnifications, c) HAADF-STEM image and ...
Beilstein J. Org. Chem. 2021, 17, 2377–2384, doi:10.3762/bjoc.17.154
Graphical Abstract
Figure 1: Structure of metronidazole (1).
Figure 2: Chemical structures of some metronidazole derivatives with different biological activity.
Figure 3: Crystal structure of compound 3. Colour codes: carbon = grey, mitrogen = blue, oxygen = red, hydrog...
Scheme 1: Reagents and conditions: (a) TsCl, Et3N, dry DCM, DMAP, 0 °C to room temperature, 5 h, 96%; (b) NaN3...
Figure 4: Crystal structure of 1H-1,2,3-triazole compound 5c: Colour codes: carbon = grey, nitrogen = blue, o...
Scheme 2: Reagents and conditions: (a) acid chlorides 6a–e, pyridine, dry DCM, DMAP, room temperature, 4–5 h,...
Figure 5: Crystal structures of compound 7b. Colour codes: carbon = grey, nitrogen = blue, oxygen = red, hydr...
Figure 6: General structural feature of the synthesized molecules 5.
Figure 7: The graph representing the antifungal activity of Didymella sp. against compounds 5a–i and 7a–e.
Figure 8: The graph representing the antibacterial activity of E. coli against compounds 5a–i and 7a–e.
Beilstein J. Org. Chem. 2021, 17, 2270–2286, doi:10.3762/bjoc.17.145
Graphical Abstract
Figure 1: a) Binding interactions in the chloride channel of E. coli. and b) examples of chloride, cyanide, n...
Figure 2: a) H-bond vs anion-binding catalysis and b) activation modes in anion-binding catalysis.
Scheme 1: First proposed anion-binding mechanism in the thiourea-catalyzed acetalization of benzaldehyde.
Scheme 2: a) Thiourea-catalyzed enantioselective acyl-Pictet–Spengler reaction of tryptamine-derived imines 4...
Scheme 3: Proposed mechanism of the thiourea-catalyzed enantioselective Pictet–Spengler reaction of hydroxyla...
Scheme 4: a) Thiourea-catalyzed intramolecular Pictet–Spengler-type cyclization of hydroxylactam-derived N-ac...
Scheme 5: Enantioselective Reissert-type reactions of a) (iso)quinolines with silyl ketene acetals, and b) vi...
Figure 3: Role of the counter-anion: a) Anion acting as a spectator and b) anion participating directly as th...
Scheme 6: Enantioselective selenocyclization catalyzed by squaramide 28.
Scheme 7: Desymmetrization of meso-aziridines catalyzed by bifunctional thiourea catalyst 31.
Scheme 8: Anion-binding-catalyzed desymmetrization of a) meso-aziridines catalyzed by chiral triazolium catal...
Scheme 9: Bis-urea-catalyzed enantioselective fluorination of a) β-bromosulfides and b) β-haloamines by Gouve...
Scheme 10: a) Bifunctional thiourea anion-binding – basic/nucleophilic catalysts. Selected applications in b) ...
Scheme 11: Thiourea-catalyzed enantioselective polycyclization reaction of hydroxylactams 51 through cation–π ...
Scheme 12: Enantioselective aza-Sakurai cyclization of hydroxylactams 56 implicating additional cation–π and L...
Scheme 13: Enantioselective tail-to-head cyclization of neryl chloride derivatives.
Scheme 14: Cation–π interactions in anion binding-catalyzed asymmetric addition reactions: a) addition of indo...
Scheme 15: Bisthiourea catalyzed oxa-Pictet–Spengler reaction of indole-based alcohols and aromatic aldehydes ...
Scheme 16: Anion-binding catalyst development in the enantioselective addition of silyl ketene acetals to 1-ch...
Scheme 17: a) Macrocyclic bis-thiourea catalyst in a diastereoselective glycosylation reaction. b) Competing SN...
Scheme 18: a) Folding mechanism of oligotriazoles upon anion recognition. b) Representative tetratriazole 82 c...
Scheme 19: Switchable chiral tetratriazole catalyst 86 in the enantioselective addition of silyl ketene acetal...
Beilstein J. Org. Chem. 2021, 17, 2260–2269, doi:10.3762/bjoc.17.144
Graphical Abstract
Figure 1: Proposed structural modifications to obtain triazole derivatives 1a, b and 2a–j.
Scheme 1: Synthetic route of the triazole derivatives 1a,b, and 2a–j.
Figure 2: Asymmetric unit representation of the 1,2,3-triazole derivative 2b. Displacement ellipsoids are dra...
Figure 3: Screening of the triazole derivatives of imatinib 1a,b, and 2a–j at concentrations of 1 μM and 10 μ...
Figure 4: Interaction maps of IMT, 2c, 2d, and 2g with the BCR-Abl-1 structure (PDB code: 3PYY), showing ster...
Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139
Graphical Abstract
Figure 1: Chemical structure, numbering scheme, and resonance form of azulene.
Scheme 1: Synthesis of polyazulene-iodine (PAz-I2) and polyazulene-bromine (PAz-Br2) complexes.
Scheme 2: Synthesis of ‘true polyazulene’ 3 or 3’ by cationic polymerization.
Scheme 3: Synthesis of 1,3-polyazulene 5 by Yamamoto protocol.
Scheme 4: Synthesis of 4,7-dibromo-6-(n-alkyl)azulenes 12–14.
Scheme 5: Synthesis of (A) 4,7-diethynyl-6-(n-dodecyl)azulene (16) and (B) 4,7-polyazulene 17 containing an e...
Scheme 6: Synthesis of directly connected 4,7-polyazulenes 18–20.
Scheme 7: Synthesis of (A) tert-butyl N-(6-bromoazulen-2-yl)carbamate (27), (B) dimeric aminoazulene 29, and ...
Figure 2: Iminium zwitterionic resonance forms of poly[2(6)-aminoazulene] 31.
Scheme 8: Synthesis of poly{1,3-bis[2-(3-alkylthienyl)]azulene} 33–38.
Scheme 9: Synthesis of polymer ruthenium complexes 40–43.
Scheme 10: Synthesis of 4,7-polyazulenes 45 containing a thienyl linker.
Scheme 11: Synthesis of azulene-bithiophene 48 and azulene-benzothiadiazole 52 copolymers. Conditions: (a): (i...
Scheme 12: Synthesis of azulene-benzodithiophene copolymer 54 and azulene-bithiophene copolymer 56.
Scheme 13: Synthesis of (A) 5,5’-bis(trimethylstannyl)-3,3’-didodecyl-2,2’-bithiophene (60) and (B) azulene-bi...
Scheme 14: Synthesis of 1,3-bisborylated azulene 67.
Scheme 15: Synthesis of D–A-type azulene-DPP copolymers 69, 71, and 72. Conditions: (a) Pd(PPh3)4, K2CO3, Aliq...
Scheme 16: Synthesis of the key precursor TBAzDI 79.
Scheme 17: Synthesis of TBAzDI-based polymers 81 and 83. Conditions: (a) P(o-tol)3, Pd2(dba)3, PivOH, Cs2CO3, ...
Scheme 18: Synthesis of (A) 1,3-dibromo-2-arylazulene 92–98 and (B) 2-arylazulene-thiophene copolymers 99–101.
Scheme 19: Synthesis of (A) poly[2,7-(9,9-dialkylfluorenyl)-alt-(1’,3’-azulenyl)] 106–109, (B) 1,3-bis(7-bromo...
Scheme 20: Synthesis of azulene-fluorene copolymers 117–121 containing varying ratios of 1,3- and 4,7-connecte...
Scheme 21: Synthesis of (A) 2,6-dibromoazulene (125), (B) azulene-fluorene copolymer 126, and (C) azulene-fluo...
Scheme 22: Synthesis of 2-arylazulene-fluorene copolymers 131–134.
Scheme 23: Synthesis of azulene-fluorene-benzothiadiazole terpolymers 136–138.
Scheme 24: Synthesis of azulene-carbazole-benzothiadiazole-conjugated polymers 140–144.
Scheme 25: Synthesis of (A) azulene-2-yl methacrylate (146) and (B) the triazole-containing azulene methacryla...
Scheme 26: Synthesis of (A) azulene methacrylate polymer 151 and (B) triazole-containing azulene methacrylate ...
Scheme 27: Synthesis of azulene methyl methacrylate polymers 154, 155 (A and B) and azulene-sulfobetaine metha...
Beilstein J. Org. Chem. 2021, 17, 1828–1848, doi:10.3762/bjoc.17.125
Graphical Abstract
Figure 1: A schematic representation of 16-mer ASOs in different designs. White circles represent unmodified ...
Figure 2: Structures of 5-(1-propargylamino)-2’-deoxyuridine (A) and 2’-aminoethoxy-5-propargylaminouridine (...
Beilstein J. Org. Chem. 2021, 17, 1600–1628, doi:10.3762/bjoc.17.114
Graphical Abstract
Figure 1: Some significant triazole derivatives [8,23-27].
Scheme 1: A general comparison between synthetic routes for disubstituted 1,2,3-triazole derivatives and full...
Scheme 2: Synthesis of formyltriazoles 3 from the treatment of α-bromoacroleins 1 with azides 2.
Scheme 3: A probable mechanism for the synthesis of formyltriazoles 5 from the treatment of α-bromoacroleins 1...
Scheme 4: Synthesis of 1,4,5-trisubstituted 1,2,3-triazoles 8 from the reaction of aryl azides 7 with enamino...
Scheme 5: Proposed mechanism for the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles from the reaction of a...
Scheme 6: Synthesis of 1,4,5-trisubstituted 1,2,3-triazoles 11 from the reaction of primary amines 10 with 1,...
Scheme 7: The proposed mechanism for the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles 11 from the reacti...
Scheme 8: Synthesis of fully decorated 1,2,3-triazoles 19 containing a sulfur-based side chain.
Scheme 9: Mechanism for the formation of fully decorated 1,2,3-triazoles 19 containing a sulfur-based side ch...
Scheme 10: Synthesis of fully decorated 1,2,3-triazole compounds 25 through the regioselective addition and cy...
Scheme 11: A reasonable mechanism for the synthesis of fully decorated 1,2,3-triazole compounds 25 through the...
Scheme 12: Synthesis of 1,4,5-trisubstituted glycosyl-containing 1,2,3-triazole derivatives 30 from the reacti...
Scheme 13: Synthesis of 1,4,5-trisubstituted 1,2,3-triazoles 34 via intramolecular cyclization reaction of ket...
Scheme 14: Synthesis of fully decorated 1,2,3-triazoles 38 from the reaction of aldehydes 35, amines 36, and α...
Scheme 15: A reasonable mechanism for the synthesis of fully decorated 1,2,3-triazoles 38 from the reaction of...
Scheme 16: Synthesis of functionally rich double C- and N-vinylated 1,2,3-triazoles 45 and 47.
Scheme 17: Synthesis of disubstituted 4-chloro-, 4-bromo-, and 4-iodo-1,2,3-triazoles 50.
Scheme 18: a) A general route for SPAAC in polymer chemistry and b) synthesis of a novel pH-sensitive polymeri...
Scheme 19: Synthesis of 5-allenyl-1,2,3-triazoles 60 by the treatment of alkynes 57, azides 58, and propargyli...
Scheme 20: A reasonable mechanism for the synthesis of 5-allenyl-1,2,3-triazoles 60 by the treatment of alkyne...
Scheme 21: Synthesis of 5‐alkynyl-1,2,3-triazoles 69.
Scheme 22: A reasonable mechanism for the synthesis of 5‐alkynyl-1,2,3-triazoles 69.
Scheme 23: Synthesis of sulfur-cycle-fused 1,2,3-triazoles 75 and 77.
Scheme 24: A reasonable mechanism for the synthesis of sulfur-cycle-fused 1,2,3‐triazoles 75 and 77.
Scheme 25: Synthesis of 5-selanyltriazoles 85 from the reaction of ethynylstibanes 82, organic azides 83, and ...
Scheme 26: A mechanism for the synthesis of 5-selanyltriazoles 85 from the reaction of ethynylstibanes 82, org...
Scheme 27: Synthesis of trisubstituted triazoles containing an Sb substituent at position C5 in 93 and 5-unsub...
Scheme 28: Synthesis of asymmetric triazole disulfides 98 from disulfide-containing tert-butyltosyl disulfide 97...
Scheme 29: A mechanism for the synthesis of asymmetric triazole disulfides 98 from disulfide-containing tert-bu...
Scheme 30: Synthesis of triazole-fused sultams 104.
Scheme 31: Synthesis of 1,2,3-triazole-fused tricyclic heterocycles 106.
Scheme 32: A reasonable mechanism for the synthesis of 1,2,3-triazole-fused tricyclic heterocycles 106.
Scheme 33: Synthesis of 5-aryl-substituted 1,2,3-triazole derivatives 112.
Scheme 34: A reasonable mechanism for the synthesis of 5-aryl-substituted 1,2,3-triazole derivatives 112.
Scheme 35: Synthesis of 1,4,5-trisubstituted 1,2,3-triazole-5-carboxamides 119.
Scheme 36: A probable mechanism for the synthesis of 1,4,5-trisubstituted 1,2,3-triazole-5-carboxamides 119.
Scheme 37: Synthesis of fully decorated triazoles 125 via the Pd/C-catalyzed arylation of disubstituted triazo...
Scheme 38: Synthesis of triazolo[1,5-a]indolones 131.
Scheme 39: Synthesis of unsymmetrically substituted triazole-fused enediyne systems 135 and 5-aryl-4-ethynyltr...
Scheme 40: Synthesis of Pd/Cu-BNP 139 and application of 139 in the synthesis of polycyclic triazoles 142.
Scheme 41: A probable mechanism for the synthesis of polycyclic triazoles 142.
Scheme 42: Synthesis of highly functionalized 1,2,3-triazole-fused 5-, 6-, and 7-membered rings 152–154.
Scheme 43: A probable mechanism for the synthesis of highly functionalized 1,2,3-triazole-fused 5-, 6-, and 7-...
Scheme 44: Synthesis of fully functionalized 1,2,3-triazolo-fused chromenes 162, 164, and 166 via the intramol...
Scheme 45: Ru-catalyzed synthesis of fully decorated triazoles 172.
Scheme 46: Synthesis of 4-cyano-1,2,3-triazoles 175.
Scheme 47: Synthesis of functionalized triazoles from the reaction of 1-alkyltriazenes 176 and azides 177 and ...
Scheme 48: Mechanism for the synthesis of functionalized triazoles from the reaction of 1-alkyltriazenes 176 a...
Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98
Graphical Abstract
Figure 1: Double-headed nucleosides. B1 and B2 = nucleobases or heterocyclic/carbocyclic moieties; L = linker....
Scheme 1: Synthesis of 2′-(pyrimidin-1-yl)methyl- or 2′-(purin-9-yl)methyl-substituted double-headed nucleosi...
Scheme 2: Synthesis of double-headed nucleoside 7 having two cytosine moieties.
Scheme 3: Synthesis of double-headed nucleoside 2′-deoxy-2′-C-(2-(thymine-1-yl)ethyl)-uridine (11).
Scheme 4: Double-headed nucleosides 14 and 15 obtained by click reaction.
Scheme 5: Synthesis of the double-headed nucleoside 19.
Scheme 6: Synthesis of the double-headed nucleosides 24 and 25.
Scheme 7: Synthesis of double-headed nucleosides 28 and 29.
Scheme 8: Synthesis of double-headed nucleoside 33.
Scheme 9: Synthesis of double-headed nucleoside 37.
Scheme 10: Synthesis of the double-headed nucleoside 1-(5′-O-(4,4′-dimethoxytrityl)-2′-C-((4-(pyren-1-yl)-1,2,...
Scheme 11: Synthesis of triazole-containing double-headed ribonucleosides 46a–c and 50a–e.
Scheme 12: Synthesis of double-headed nucleosides 54a–g.
Scheme 13: Synthesis of double-headed nucleosides 59 and 60.
Scheme 14: Synthesis of the double-headed nucleosides 63 and 64.
Scheme 15: Synthesis of double-headed nucleosides 66a–c.
Scheme 16: Synthesis of benzoxazole-containing double-headed nucleosides 69 and 71 from 5′-amino-5′-deoxynucle...
Scheme 17: Synthesis of 4′-C-((N6-benzoyladenin-9-yl)methyl)thymidine (75) and 4′-C-((thymin-1-yl)methyl)thymi...
Scheme 18: Synthesis of double-headed nucleosides 5′-(adenine-9-yl)-5′-deoxythymidine (79) and 5′-(adenine-9-y...
Scheme 19: Synthesis of double-headed nucleosides 85–87 via reversed nucleosides methodology.
Scheme 20: Double-headed nucleosides 91 and 92 derived from ω-terminal-acetylenic sugar derivatives 90a,b.
Scheme 21: Synthesis of double-headed nucleosides 96a–g.
Scheme 22: Synthesis of double-headed nucleosides 100 and 103.
Scheme 23: Double-headed nucleosides 104 and 105 with a triazole motif.
Scheme 24: Synthesis of the double-headed nucleosides 107 and 108.
Scheme 25: Synthesis of double-headed nucleoside 110 with additional nucleobase in 5′-(S)-C-position joined th...
Scheme 26: Synthesis of double-headed nucleosides 111–113 with additional nucleobases in the 5′-(S)-C-position...
Scheme 27: Synthesis of double-headed nucleoside 114 by click reaction.
Scheme 28: Synthesis of double-headed nucleosides 118 with an additional nucleobase at the 5′-(S)-C-position.
Scheme 29: Synthesis of bicyclic double-headed nucleoside 122.
Scheme 30: Synthesis of double-headed nucleosides 125a–c derived from 2′-amino-LNA.
Scheme 31: Double-headed nucleoside 127 obtained by click reaction.
Scheme 32: Synthesis of double-headed nucleoside 130.
Scheme 33: Double-headed nucleosides 132a–d and 134a–d synthesized by Sonogashira cross coupling reaction.
Scheme 34: Synthesis of double-headed nucleosides 137 and 138 via Suzuki coupling.
Scheme 35: Synthesis of double-headed nucleosides 140 and 141 via Sonogashira cross coupling reaction.
Scheme 36: Synthesis of double-headed nucleoside 143.
Scheme 37: Synthesis of the double-headed nucleoside 146.
Scheme 38: Synthesis of 5-C-alkynyl-functionalized double-headed nucleosides 151a–d.
Scheme 39: Synthesis of 5-C-triazolyl-functionalized double-headed nucleosides 154a, b.
Scheme 40: Synthesis of double-headed nucleosides 157a–c.
Scheme 41: Synthesis of double-headed nucleoside 159, phosphoramidite 160 and the corresponding nucleotide mon...
Scheme 42: Synthesis of double-headed nucleoside 163, phosphoramidite 164 and the corresponding nucleotide mon...
Scheme 43: Synthesis of double-headed nucleoside 167, phosphoramidite 168, and the corresponding nucleotide mo...
Scheme 44: Synthesis of double-headed nucleoside 171, phosphoramidite 172, and the corresponding nucleotide mo...
Scheme 45: Synthesis of double-headed nucleoside 175, phosphoramidite 176, and the corresponding nucleotide mo...
Scheme 46: Synthesis of double-headed nucleoside 178.
Scheme 47: Synthesis of the double-headed nucleosides 181 and 183.
Scheme 48: Alternative synthesis of the double-headed nucleoside 183.
Scheme 49: Synthesis of double-headed nucleoside 188 through thermal [2 + 3] sydnone–alkyne cycloaddition reac...
Scheme 50: Synthesis of the double-headed nucleosides 190 and 191.
Scheme 51: Synthesis of 1-((5S)-2,3,4-tri-O-acetyl-5-(2,6-dichloropurin-9-yl)-β-ᴅ-xylopyranosyl)uracil (195).
Scheme 52: Synthesis of hexopyranosyl double-headed pyrimidine homonucleosides 200a–c.
Figure 2: 3′-C-Ethynyl-β-ᴅ-allopyranonucleoside derivatives 201a–f.
Scheme 53: Synthesis of 3′-C-(1,4-disubstituted-1,2,3-triazolyl)-double-headed pyranonucleosides 203–207.
Scheme 54: Synthesis of 3′-C-(1,4-disubstituted-1,2,3-triazolyl)-double-headed pyranonucleosides 208 and 209.
Scheme 55: Synthesis of 3′-C-(1,4-disubstituted-1,2,3-triazolyl)-double-headed pyranonucleoside 210.
Scheme 56: Synthesis of double-headed acyclic nucleosides (2S,3R)-1,4-bis(thymine-1-yl)butane-2,3-diol (213a) ...
Scheme 57: Synthesis of double-headed acyclic nucleosides (2R,3S)-1,4-bis(thymine-1-yl)butane-2,3-diol (213c) ...
Scheme 58: Synthesis of double-headed acetylated 1,3,4-oxadiazino[6,5-b]indolium-substituted C-nucleosides 218b...
Scheme 59: Synthesis of double-headed acyclic nucleoside 222.
Scheme 60: Synthesis of functionalized 1,2-bis(1,2,4-triazol-3-yl)ethane-1,2-diols 223a–f.
Scheme 61: Synthesis of acyclic double-headed 1,2,4-triazino[5,6-b]indole C-nucleosides 226–231.
Scheme 62: Synthesis of double-headed 1,3,4-thiadiazoline, 1,3,4-oxadiazoline, and 1,2,4-triazoline acyclo C-n...
Scheme 63: Synthesis of double-headed acyclo C-nucleosides 240–242.
Scheme 64: Synthesis of double-headed acyclo C-nucleoside 246.
Scheme 65: Synthesis of acyclo double-headed nucleoside 250.
Scheme 66: Synthesis of acyclo double-headed nucleoside 253.
Scheme 67: Synthesis of acyclo double-headed nucleosides 259a–d.
Scheme 68: Synthesis of acyclo double-headed nucleoside 261.
Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90
Graphical Abstract
Figure 1: Representative shares of the global F&F market (2018) segmented on their applications [1].
Figure 2: General structure of an international fragrance company [2].
Figure 3: The Michael Edwards fragrance wheel.
Figure 4: Examples of oriental (1–3), woody (4–7), fresh (8–10), and floral (11 and 12) notes.
Figure 5: A basic depiction of batch vs flow.
Scheme 1: Examples of reactions for which flow processing outperforms batch.
Scheme 2: Some industrially important aldol-based transformations.
Scheme 3: Biphasic continuous aldol reactions of acetone and various aldehydes.
Scheme 4: Aldol synthesis of 43 in flow using LiHMDS as the base.
Scheme 5: A semi-continuous synthesis of doravirine (49) involving a key aldol reaction.
Scheme 6: Enantioselective aldol reaction using 5-(pyrrolidin-2-yl)tetrazole (51) as catalyst in a microreact...
Scheme 7: Gröger's example of asymmetric aldol reaction in aqueous media.
Figure 6: Immobilised reagent column reactor types.
Scheme 8: Photoinduced thiol–ene coupling preparation of silica-supported 5-(pyrrolidin-2-yl)tetrazole 63 and...
Scheme 9: Continuous-flow approach for enantioselective aldol reactions using the supported catalyst 67.
Scheme 10: Ötvös’ employment of a solid-supported peptide aldol catalyst in flow.
Scheme 11: The use of proline tetrazole packed in a column for aldol reaction between cyclohexanone (65) and 2...
Scheme 12: Schematic diagram of an aminosilane-grafted Si-Zr-Ti/PAI-HF reactor for continuous-flow aldol and n...
Scheme 13: Continuous-flow condensation for the synthesis of the intermediate 76 to nabumetone (77) and Microi...
Scheme 14: Synthesis of ψ-Ionone (80) in continuous-flow via aldol condensation between citral (79) and aceton...
Scheme 15: Synthesis of β-methyl-ionones (83) from citral (79) in flow. The steps are separately described, an...
Scheme 16: Continuous-flow synthesis of 85 from 84 described by Gavriilidis et al.
Scheme 17: Continuous-flow scCO2 apparatus for the synthesis of 2-methylpentanal (87) and the self-condensed u...
Scheme 18: Chen’s two-step flow synthesis of coumarin (90).
Scheme 19: Pechmann condensation for the synthesis of 7-hydroxyxcoumarin (93) in flow. The setup extended to c...
Scheme 20: Synthesis of the dihydrojasmonate 35 exploiting nitro derivative proposed by Ballini et al.
Scheme 21: Silica-supported amines as heterogeneous catalyst for nitroaldol condensation in flow.
Scheme 22: Flow apparatus for the nitroaldol condensation of p-hydroxybenzaldehyde (102) to nitrostyrene 103 a...
Scheme 23: Nitroaldol reaction of 64 to 105 employing a quaternary ammonium functionalised PANF.
Scheme 24: Enantioselective nitroaldol condensation for the synthesis of 108 under flow conditions.
Scheme 25: Enatioselective synthesis of 1,2-aminoalcohol 110 via a copper-catalysed nitroaldol condensation.
Scheme 26: Examples of Knoevenagel condensations applied for fragrance components.
Scheme 27: Flow apparatus for Knoevenagel condensation described in 1989 by Venturello et al.
Scheme 28: Knoevenagel reaction using a coated multichannel membrane microreactor.
Scheme 29: Continuous-flow apparatus for Knoevenagel condensation employing sugar cane bagasse as support deve...
Scheme 30: Knoevenagel reaction for the synthesis of 131–135 in flow using an amine-functionalised silica gel. ...
Scheme 31: Continuous-flow synthesis of compound 137, a key intermediate for the synthesis of pregabalin (138)...
Scheme 32: Continuous solvent-free apparatus applied for the synthesis of compounds 140–143 using a TSE. Throu...
Scheme 33: Lewis et al. developed a spinning disc reactor for Darzens condensation of 144 and a ketone to furn...
Scheme 34: Some key industrial applications of conjugate additions in the F&F industry.
Scheme 35: Continuous-flow synthesis of 4-(2-hydroxyethyl)thiomorpholine 1,1-dioxide (156) via double conjugat...
Scheme 36: Continuous-flow system for Michael addition using CsF on alumina as the catalyst.
Scheme 37: Calcium chloride-catalysed asymmetric Michael addition using an immobilised chiral ligand.
Scheme 38: Continuous multistep synthesis for the preparation of (R)-rolipram (173). Si-NH2: primary amine-fun...
Scheme 39: Continuous-flow Michael addition using ion exchange resin Amberlyst® A26.
Scheme 40: Preparation of the heterogeneous catalyst 181 developed by Paixão et al. exploiting Ugi multicompon...
Scheme 41: Continuous-flow system developed by the Paixão’s group for the preparation of Michael asymmetric ad...
Scheme 42: Continuous-flow synthesis of nitroaldols catalysed by supported catalyst 184 developed by Wennemers...
Scheme 43: Heterogenous polystyrene-supported catalysts developed by Pericàs and co-workers.
Scheme 44: PANF-supported pyrrolidine catalyst for the conjugate addition of cyclohexanone (65) and trans-β-ni...
Scheme 45: Synthesis of (−)-paroxetine precursor 195 developed by Ötvös, Pericàs, and Kappe.
Scheme 46: Continuous-flow approach for the 5-step synthesis of (−)-oseltamivir (201) as devised by Hayashi an...
Scheme 47: Continuous-flow enzyme-catalysed Michael addition.
Scheme 48: Continuous-flow copper-catalysed 1,4 conjugate addition of Grignard reagents to enones. Reprinted w...
Scheme 49: A collection of commonly encountered hydrogenation reactions.
Figure 7: The ThalesNano H-Cube® continuous-flow hydrogenator.
Scheme 50: Chemoselective reduction of an α,β-unsaturated ketone using the H-Cube® reactor.
Scheme 51: Incorporation of Lindlar’s catalyst into the H-Cube® reactor for the reduction of an alkyne.
Scheme 52: Continuous-flow semi-hydrogenation of alkyne 208 to 209 using SACs with H-Cube® system.
Figure 8: The standard setups for tube-in-tube gas–liquid reactor units.
Scheme 53: Homogeneous hydrogenation of olefins using a tube-in-tube reactor setup.
Scheme 54: Recyclable heterogeneous flow hydrogenation system.
Scheme 55: Leadbeater’s reverse tube-in-tube hydrogenation system for olefin reductions.
Scheme 56: a) Hydrogenation using a Pd-immobilised microchannel reactor (MCR) and b) a representation of the i...
Scheme 57: Hydrogenation of alkyne 238 exploiting segmented flow in a Pd-immobilised capillary reactor.
Scheme 58: Continuous hydrogenation system for the preparation of cyrene (241) from (−)-levoglucosenone (240).
Scheme 59: Continuous hydrogenation system based on CSMs developed by Hornung et al.
Scheme 60: Chemoselective reduction of carbonyls (ketones over aldehydes) in flow.
Scheme 61: Continuous system for the semi-hydrogenation of 256 and 258, developed by Galarneau et al.
Scheme 62: Continuous synthesis of biodiesel fuel 261 from lignin-derived furfural acetone (260).
Scheme 63: Continuous synthesis of γ-valerolacetone (263) via CTH developed by Pineda et al.
Scheme 64: Continuous hydrogenation of lignin-derived biomass (products 265, 266, and 267) using a sustainable...
Scheme 65: Ru/C or Rh/C-catalysed hydrogenation of arene in flow as developed by Sajiki et al.
Scheme 66: Polysilane-immobilized Rh–Pt-catalysed hydrogenation of arenes in flow by Kobayashi et al.
Scheme 67: High-pressure in-line mixing of H2 for the asymmetric reduction of 278 at pilot scale with a 73 L p...
Figure 9: Picture of the PFR employed at Eli Lilly & Co. for the continuous hydrogenation of 278 [287]. Reprinted ...
Scheme 68: Continuous-flow asymmetric hydrogenation using Oppolzer's sultam 280 as chiral auxiliary.
Scheme 69: Some examples of industrially important oxidation reactions in the F&F industry. CFL: compact fluor...
Scheme 70: Gold-catalysed heterogeneous oxidation of alcohols in flow.
Scheme 71: Uozumi’s ARP-Pt flow oxidation protocol.
Scheme 72: High-throughput screening of aldehyde oxidation in flow using an in-line GC.
Scheme 73: Permanganate-mediated Nef oxidation of nitroalkanes in flow with the use of in-line sonication to p...
Scheme 74: Continuous-flow aerobic anti-Markovnikov Wacker oxidation.
Scheme 75: Continuous-flow oxidation of 2-benzylpyridine (312) using air as the oxidant.
Scheme 76: Continuous-flow photo-oxygenation of monoterpenes.
Scheme 77: A tubular reactor design for flow photo-oxygenation.
Scheme 78: Glucose oxidase (GOx)-mediated continuous oxidation of glucose using compressed air and the FFMR re...
Scheme 79: Schematic continuous-flow sodium hypochlorite/TEMPO oxidation of alcohols.
Scheme 80: Oxidation using immobilised TEMPO (344) was developed by McQuade et al.
Scheme 81: General protocol for the bleach/catalytic TBAB oxidation of aldehydes and alcohols.
Scheme 82: Continuous-flow PTC-assisted oxidation using hydrogen peroxide. The process was easily scaled up by...
Scheme 83: Continuous-flow epoxidation of cyclohexene (348) and in situ preparation of m-CPBA.
Scheme 84: Continuous-flow epoxidation using DMDO as oxidant.
Scheme 85: Mukayama aerobic epoxidation optimised in flow mode by the Favre-Réguillon group.
Scheme 86: Continuous-flow asymmetric epoxidation of derivatives of 359 exploiting a biomimetic iron catalyst.
Scheme 87: Continuous-flow enzymatic epoxidation of alkenes developed by Watts et al.
Scheme 88: Engineered multichannel microreactor for continuous-flow ozonolysis of 366.
Scheme 89: Continuous-flow synthesis of the vitamin D precursor 368 using multichannel microreactors. MFC: mas...
Scheme 90: Continuous ozonolysis setup used by Kappe et al. for the synthesis of various substrates employing ...
Scheme 91: Continuous-flow apparatus for ozonolysis as developed by Ley et al.
Scheme 92: Continuous-flow ozonolysis for synthesis of vanillin (2) using a film-shear flow reactor.
Scheme 93: Examples of preparative methods for ajoene (386) and allicin (388).
Scheme 94: Continuous-flow oxidation of thioanisole (389) using styrene-based polymer-supported peroxytungstat...
Scheme 95: Continuous oxidation of thiosulfinates using Oxone®-packed reactor.
Scheme 96: Continuous-flow electrochemical oxidation of thioethers.
Scheme 97: Continuous-flow oxidation of 400 to cinnamophenone (235).
Scheme 98: Continuous-flow synthesis of dehydrated material 401 via oxidation of methyl dihydrojasmonate (33).
Scheme 99: Some industrially important transformations involving Grignard reagents.
Scheme 100: Grachev et al. apparatus for continuous preparation of Grignard reagents.
Scheme 101: Example of fluidized Mg bed reactor with NMR spectrometer as on-line monitoring system.
Scheme 102: Continuous-flow synthesis of Grignard reagents and subsequent quenching reaction.
Figure 10: Membrane-based, liquid–liquid separator with integrated pressure control [52]. Adapted with permission ...
Scheme 103: Continuous-flow synthesis of 458, an intermediate to fluconazole (459).
Scheme 104: Continuous-flow synthesis of ketones starting from benzoyl chlorides.
Scheme 105: A Grignard alkylation combining CSTR and PFR technologies with in-line infrared reaction monitoring....
Scheme 106: Continuous-flow preparation of 469 from Grignard addition of methylmagnesium bromide.
Scheme 107: Continuous-flow synthesis of Grignard reagents 471.
Scheme 108: Preparation of the Grignard reagent 471 using CSTR and the continuous process for synthesis of the ...
Scheme 109: Continuous process for carboxylation of Grignard reagents in flow using tube-in-tube technology.
Scheme 110: Continuous synthesis of propargylic alcohols via ethynyl-Grignard reagent.
Scheme 111: Silica-supported catalysed enantioselective arylation of aldehydes using Grignard reagents in flow ...
Scheme 112: Acid-catalysed rearrangement of citral and dehydrolinalool derivatives.
Scheme 113: Continuous stilbene isomerisation with continuous recycling of photoredox catalyst.
Scheme 114: Continuous-flow synthesis of compound 494 as developed by Ley et al.
Scheme 115: Selected industrial applications of DA reaction.
Scheme 116: Multistep flow synthesis of the spirocyclic structure 505 via employing DA cycloaddition.
Scheme 117: Continuous-flow DA reaction developed in a plater flow reactor for the preparation of the adduct 508...
Scheme 118: Continuous-flow DA reaction using a silica-supported imidazolidinone organocatalyst.
Scheme 119: Batch vs flow for the DA reaction of (cyclohexa-1,5-dien-1-yloxy)trimethylsilane (513) with acrylon...
Scheme 120: Continuous-flow DA reaction between 510 and 515 using a shell-core droplet system.
Scheme 121: Continuous-flow synthesis of bicyclic systems from benzyne precursors.
Scheme 122: Continuous-flow synthesis of bicyclic scaffolds 527 and 528 for further development of potential ph...
Scheme 123: Continuous-flow inverse-electron hetero-DA reaction to pyridine derivatives such as 531.
Scheme 124: Comparison between batch and flow for the synthesis of pyrimidinones 532–536 via retro-DA reaction ...
Scheme 125: Continuous-flow coupled with ultrasonic system for preparation of ʟ-ascorbic acid derivatives 539 d...
Scheme 126: Two-step continuous-flow synthesis of triazole 543.
Scheme 127: Continuous-flow preparation of triazoles via CuAAC employing 546-based heterogeneous catalyst.
Scheme 128: Continuous-flow synthesis of compounds 558 through A3-coupling and 560 via AgAAC both employing the...
Scheme 129: Continuous-flow photoinduced [2 + 2] cycloaddition for the preparation of bicyclic derivatives of 5...
Scheme 130: Continuous-flow [2 + 2] and [5 + 2] cycloaddition on large scale employing a flow reactor developed...
Scheme 131: Continuous-flow preparation of the tricyclic structures 573 and 574 starting from pyrrole 570 via [...
Scheme 132: Continuous-flow [2 + 2] photocyclization of cinnamates.
Scheme 133: Continuous-flow preparation of cyclobutane 580 on a 5-plates photoreactor.
Scheme 134: Continuous-flow [2 + 2] photocycloaddition under white LED lamp using heterogeneous PCN as photocat...
Figure 11: Picture of the parallel tube flow reactor (PTFR) "The Firefly" developed by Booker-Milburn et al. a...
Scheme 135: Continuous-flow acid-catalysed [2 + 2] cycloaddition between silyl enol ethers and acrylic esters.
Scheme 136: Continuous synthesis of lactam 602 using glass column reactors.
Scheme 137: In situ generation of ketenes for the Staudinger lactam synthesis developed by Ley and Hafner.
Scheme 138: Application of [2 + 2 + 2] cycloadditions in flow employed by Ley et al.
Scheme 139: Examples of FC reactions applied in F&F industry.
Scheme 140: Continuous-flow synthesis of ibuprofen developed by McQuade et al.
Scheme 141: The FC acylation step of Jamison’s three-step ibuprofen synthesis.
Scheme 142: Synthesis of naphthalene derivative 629 via FC acylation in microreactors.
Scheme 143: Flow system for rapid screening of catalysts and reaction conditions developed by Weber et al.
Scheme 144: Continuous-flow system developed by Buorne, Muller et al. for DSD optimisation of the FC acylation ...
Scheme 145: Continuous-flow FC acylation of alkynes to yield β-chlorovinyl ketones such as 638.
Scheme 146: Continuous-flow synthesis of tonalide (619) developed by Wang et al.
Scheme 147: Continuous-flow preparation of acylated arene such as 290 employing Zr4+-β-zeolite developed by Kob...
Scheme 148: Flow system applied on an Aza-FC reaction catalysed by the thiourea catalyst 648.
Scheme 149: Continuous hydroformylation in scCO2.
Scheme 150: Two-step flow synthesis of aldehyde 655 through a sequential Heck reaction and subsequent hydroform...
Scheme 151: Single-droplet (above) and continuous (below) flow reactors developed by Abolhasani et al. for the ...
Scheme 152: Continuous hydroformylation of 1-dodecene (655) using a PFR-CSTR system developed by Sundmacher et ...
Scheme 153: Continuous-flow synthesis of the aldehyde 660 developed by Eli Lilly & Co. [32]. Adapted with permissio...
Scheme 154: Continuous asymmetric hydroformylation employing heterogenous catalst supported on carbon-based sup...
Scheme 155: Examples of acetylation in F&F industry: synthesis of bornyl (S,R,S-664) and isobornyl (S,S,S-664) ...
Scheme 156: Continuous-flow preparation of bornyl acetate (S,R,S-664) employing the oscillating flow reactor.
Scheme 157: Continuous-flow synthesis of geranyl acetate (666) from acetylation of geraniol (343) developed by ...
Scheme 158: 12-Ttungstosilicic acid-supported silica monolith-catalysed acetylation in flow.
Scheme 159: Continuous-flow preparation of cyclopentenone 676.
Scheme 160: Two-stage synthesis of coumarin (90) via acetylation of salicylaldehyde (88).
Scheme 161: Intensification process for acetylation of 5-methoxytryptamine (677) to melatonin (678) developed b...
Scheme 162: Examples of macrocyclic musky odorants both natural (679–681) and synthetic (682 and 683).
Scheme 163: Flow setup combined with microwave for the synthesis of macrocycle 686 via RCM.
Scheme 164: Continuous synthesis of 2,5-dihydro-1H-pyrroles via ring-closing metathesis.
Scheme 165: Continuous-flow metathesis of 485 developed by Leadbeater et al.
Figure 12: Comparison between RCM performed using different routes for the preparation of 696. On the left the...
Scheme 166: Continuous-flow RCM of 697 employed the solid-supported catalyst 698 developed by Grela, Kirschning...
Scheme 167: Continuous-flow RORCM of cyclooctene employing the silica-absorbed catalyst 700.
Scheme 168: Continuous-flow self-metathesis of methyl oleate (703) employing SILP catalyst 704.
Scheme 169: Flow apparatus for the RCM of 697 using a nanofiltration membrane for the recovery and reuse of the...
Scheme 170: Comparison of loadings between RCMs performed with different routes for the synthesis of 709.
Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82
Graphical Abstract
Figure 1: Tautomeric forms of biguanide.
Figure 2: Illustrations of neutral, monoprotonated, and diprotonated structures biguanide.
Figure 3: The main approaches for the synthesis of biguanides. The core structure is obtained via the additio...
Scheme 1: The three main preparations of biguanides from cyanoguanidine.
Scheme 2: Synthesis of butylbiguanide using CuCl2 [16].
Scheme 3: Synthesis of biguanides by the direct fusion of cyanoguanidine and amine hydrochlorides [17,18].
Scheme 4: Synthesis of ethylbiguanide and phenylbiguanide as reported by Smolka and Friedreich [14].
Scheme 5: Synthesis of arylbiguanides through the reaction of cyanoguanidine with anilines in water [19].
Scheme 6: Synthesis of aryl- and alkylbiguanides by adaptations of Cohn’s procedure [20,21].
Scheme 7: Microwave-assisted synthesis of N1-aryl and -dialkylbiguanides [22,23].
Scheme 8: Synthesis of aryl- and alkylbiguanides by trimethylsilyl activation [24,26].
Scheme 9: Synthesis of phenformin analogs by TMSOTf activation [27].
Scheme 10: Synthesis of N1-(1,2,4-triazolyl)biguanides [28].
Scheme 11: Synthesis of 2-guanidinobenzazoles by addition of ortho-substituted anilines to cyanoguanidine [30,32] and...
Scheme 12: Synthesis of 2,4-diaminoquinazolines by the addition of 2-cyanoaniline to cyanoguanidine and from 3...
Scheme 13: Reactions of anthranilic acid and 2-mercaptobenzoic acid with cyanoguanidine [24,36,37].
Scheme 14: Synthesis of disubstituted biguanides with Cu(II) salts [38].
Scheme 15: Synthesis of an N1,N2,N5-trisubstituted biguanide by fusion of an amine hydrochloride and 2-cyano-1...
Scheme 16: Synthesis of N1,N5-disubstituted biguanides by the addition of anilines to cyanoguanidine derivativ...
Scheme 17: Microwave-assisted additions of piperazine and aniline hydrochloride to substituted cyanoguanidines ...
Scheme 18: Synthesis of N1,N5-alkyl-substituted biguanides by TMSOTf activation [27].
Scheme 19: Additions of oxoamines hydrochlorides to dimethylcyanoguanidine [49].
Scheme 20: Unexpected cyclization of pyridylcyanoguanidines under acidic conditions [50].
Scheme 21: Example of industrial synthesis of chlorhexidine [51].
Scheme 22: Synthesis of symmetrical N1,N5-diarylbiguanides from sodium dicyanamide [52,53].
Scheme 23: Synthesis of symmetrical N1,N5-dialkylbiguanides from sodium dicyanamide [54-56].
Scheme 24: Stepwise synthesis of unsymmetrical N1,N5-trisubstituted biguanides from sodium dicyanamide [57].
Scheme 25: Examples for the synthesis of unsymmetrical biguanides [58].
Scheme 26: Examples for the synthesis of an 1,3-diaminobenzoquinazoline derivative by the SEAr cyclization of ...
Scheme 27: Major isomers formed by the SEAr cyclization of symmetric biguanides derived from 2- and 3-aminophe...
Scheme 28: Lewis acid-catalyzed synthesis of 8H-pyrrolo[3,2-g]quinazoline-2,4-diamine [63].
Scheme 29: Synthesis of [1,2,4]oxadiazoles by the addition of hydroxylamine to dicyanamide [49,64].
Scheme 30: Principle of “bisamidine transfer” and analogy between the reactions with N-amidinopyrazole and N-a...
Scheme 31: Representative syntheses of N-amidino-amidinopyrazole hydrochloride [68,69].
Scheme 32: First examples of biguanide syntheses using N-amidino-amidinopyrazole [66].
Scheme 33: Example of “biguanidylation” of a hydrazide substrate [70].
Scheme 34: Example for the synthesis of biguanides using S-methylguanylisothiouronium iodide as “bisamidine tr...
Scheme 35: Synthesis of N-substituted N1-cyano-S-methylisothiourea precursors.
Scheme 36: Addition routes on N1-cyano-S-methylisothioureas.
Scheme 37: Synthesis of an hydroxybiguanidine from N1-cyano-S-methylisothiourea [77].
Scheme 38: Synthesis of an N1,N2,N3,N4,N5-pentaarylbiguanide from the corresponding triarylguanidine and carbo...
Scheme 39: Reactions of N,N,N’,N’-tetramethylguanidine (TMG) with carbodiimides to synthesize hexasubstituted ...
Scheme 40: Microwave-assisted addition of N,N,N’,N’-tetramethylguanidine to carbodiimides [80].
Scheme 41: Synthesis of N1-aryl heptasubstituted biguanides via a one-pot biguanide formation–copper-catalyzed ...
Scheme 42: Formation of 1,2-dihydro-1,3,5-triazine derivatives by the reaction of guanidine with excess carbod...
Scheme 43: Plausible mechanism for the spontaneous cyclization of triguanides [82].
Scheme 44: a) Formation of mono- and disubstituted (iso)melamine derivatives by the reaction of biguanides and...
Scheme 45: Reactions of 2-aminopyrimidine with carbodiimides to synthesize 2-guanidinopyrimidines as “biguanid...
Scheme 46: Non-catalyzed alternatives for the addition of 2-aminopyrimidine derivatives to carbodiimides. A) h...
Scheme 47: Addition of guanidinomagnesium halides to substituted cyanamides [90].
Scheme 48: Microwave-assisted synthesis of [11C]metformin by the reaction of 11C-labelled dimethylcyanamide an...
Scheme 49: Formation of 4-amino-6-dimethylamino[1,3,5]triazin-2-ol through the reaction of Boc-guanidine and d...
Scheme 50: Formation of 1,3,5-triazine derivatives via the addition of guanidines to substituted cyanamides [92].
Scheme 51: Synthesis of biguanide by the reaction of O-alkylisourea and guanidine [93].
Scheme 52: Aromatic nucleophilic substitution of guanidine on 2-O-ethyl-1,3,5-triazine [95].
Scheme 53: Synthesis of N1,N2-disubstituted biguanides by the reaction of guanidine and thioureas in the prese...
Scheme 54: Cyclization reactions involving condensations of guanidine(-like) structures with thioureas [97,98].
Scheme 55: Condensations of guanidine-like structures with thioureas [99,100].
Scheme 56: Condensations of guanidines with S-methylisothioureas [101,102].
Scheme 57: Addition of 2-amino-1,3-diazaaromatics to S-alkylisothioureas [103,104].
Scheme 58: Addition of guanidines to 2-(methylsulfonyl)pyrimidines [105].
Scheme 59: An example of a cyclodesulfurization reaction to a fused 3,5-diamino-1,2,4-triazole [106].
Scheme 60: Ring-opening reactions of 1,3-diaryl-2,4-bis(arylimino)-1,3-diazetidines [107].
Scheme 61: Formation of 3,5-diamino-1,2,4-triazole derivatives via addition of hydrazines to 1,3-diazetidine-2...
Scheme 62: Formation of a biguanide via the addition of aniline to 1,2,4-thiadiazol-3,5-diamines, ring opening...
Figure 4: Substitution pattern of biguanides accessible by synthetic pathways a–h.
Beilstein J. Org. Chem. 2021, 17, 908–931, doi:10.3762/bjoc.17.76
Graphical Abstract
Figure 1: Structures of the chemically modified oligonucleotides (A) N3' → P5' phosphoramidate linkage, (B) a...
Scheme 1: Synthesis of a N3' → P5' phosphoramidate linkage by solid-phase synthesis. (a) dichloroacetic acid;...
Figure 2: Crystal structures of (A) N3' → P5' phosphoramidate DNA (PDB ID 363D) [71] and (B) amide (AM1) RNA in c...
Scheme 2: Synthesis of a phosphorodithioate linkage by solid-phase synthesis. (a) detritylation; (b) tetrazol...
Figure 3: Close-up view of a key interaction between the PS2-modified antithrombin RNA aptamer and thrombin i...
Scheme 3: Synthesis of the (S)-GNA thymine phosphoramidite from (S)-glycidyl 4,4'-dimethoxytrityl ether. (a) ...
Figure 4: Surface models of the crystal structures of RNA dodecamers with single (A) (S)-GNA-T (PDB ID 5V1L) [54]...
Figure 5: Structures of 2'-O-alkyl modifications. (A) 2'-O-methoxy RNA (2'-OMe RNA), (B) 2'-O-(2-methoxyethyl...
Scheme 4: Synthesis of the 2'-OMe uridine from 3',5'-O-(tetraisopropyldisiloxane-1,3-diyl)uridine. (a) Benzoy...
Scheme 5: Synthesis of the 2'-O-MOE uridine from uridine. (a) (PhO)2CO, NaHCO3, DMA, 100 °C; (b) Al(OCH2CH2OCH...
Figure 6: Structure of 2'-O-(2-methoxyethyl)-RNA (MOE-RNA). (A) View into the minor groove of an A-form DNA d...
Figure 7: Structures of locked nucleic acids (LNA)/bridged nucleic acids (BNA) modifications. (A) LNA/BNA, (B...
Scheme 6: Synthesis of the uridine LNA phosphoramidite. (a) i) NaH, BnBr, DMF, ii) acetic anhydride, pyridine...
Scheme 7: Synthesis of the 2'-fluoroarabinothymidine. (a) 30% HBr in acetic acid; (b) 2,4-bis-O-(trimethylsil...
Figure 8: Sugar puckers of arabinose (ANA) and arabinofluoro (FANA) nucleic acids compared with the puckers o...
Figure 9: Structures of C4'-modified nucleic acids. (A) 4'-methoxy, (B) 4'-(2-methoxyethoxy), (C) 2',4'-diflu...
Scheme 8: Synthesis of the 4'-F-rU phosphoramidite. (a) AgF, I2, dichloromethane, tetrahydrofuran; (b) NH3, m...
Scheme 9: Synthesis of the thymine FHNA phosphoramidite. (a) thymine, 1,8-diazabicyclo[5.4.0]undec-7-ene, ace...
Scheme 10: Synthesis of the thymine Ara-FHNA phosphoramidite. (a) i) trifluoromethanesulfonic anhydride, pyrid...
Figure 10: Crystal structures of (A) FHNA and (B) Ara-FHNA in modified A-form DNA decamers (PDB IDs 3Q61 and 3...
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.