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Search for "o-chloranil" in Full Text gives 9 result(s) in Beilstein Journal of Organic Chemistry.
Synthesis, structure, ionochromic and cytotoxic properties of new 2-(indolin-2-yl)-1,3-tropolones
- Yurii A. Sayapin,
- Eugeny A. Gusakov,
- Inna O. Tupaeva,
- Alexander D. Dubonosov,
- Igor V. Dorogan,
- Valery V. Tkachev,
- Anna S. Goncharova,
- Gennady V. Shilov,
- Natalia S. Kuznetsova,
- Svetlana Y. Filippova,
- Tatyana A. Krasnikova,
- Yanis A. Boumber,
- Alexey Y. Maksimov,
- Sergey M. Aldoshin and
- Vladimir I. Minkin
Beilstein J. Org. Chem. 2025, 21, 358–368, doi:10.3762/bjoc.21.26
- Comprehensive Cancer Center at University of Alabama at Birmingham, Department of Medicine, Section of Hematology/Oncology, Heersink School of Medicine, Birmingham, AL 35233, USA 10.3762/bjoc.21.26 Abstract The acid-catalyzed reaction of benzo[e(g)] derivatives of 2,3,3-trimethylindolenines with o-chloranil
- -(1,1-Dimethyl-1H-benzo[e]indolin-2-yl)-5,6,7-trichloro-1,3-tropolone exhibited high in vitro cytotoxic activity against A431 skin cancer and H1299 lung cancer cell lines. Keywords: cytotoxic activity; fluorescence; o-chloranil; quantum chemical DFT calculations; 1,3-tropolones; X-ray diffraction
- contraction and the formation of 2-azabicyclic products and pyridino[1,2-a]benzo[e]indol-10,11-diones [24]. o-Chloranil was found to be the most efficient 1,2-benzoquinone, which engages in o-quinone ring-expansion reactions with 2,3,3-trimethylindolenines to form hard-to-reach polychlorinated derivatives of
Graphical Abstract
Scheme 1: Synthesis of 2-hetaryl-substituted 1,3-tropolones 1.
Scheme 2: Synthesis of 1,3-tropolones 7a,b and 8a,b. Reagents and conditions: method A: dioxane, reflux; meth...
Figure 1: Structural characteristics of (NH) and (OH) tautomeric forms of compounds 7 and 8 in the gas phase ...
Figure 2: Scheme of HMBC correlations of compound 7a in DMSO-d6.
Figure 3: Molecular structure of 2-(3,3-dimethyl-3H-benzo[g]indolin-2-yl)-5,6,7-trichloro-1,3-tropolone (7b).
Figure 4: Result of matching structures of 7b (solid lines) and 2-(3,3-dimethylindolin-2-yl)-5,6,7-trichloro-...
Figure 5: Absorption and emission spectra of compound 8b in acetonitrile before (1,1’) (c 2.5 × 10−5 mol L–1)...
Scheme 3: Possible binding mode of 7 and 8 with CN− and F−.
Figure 6: Dose–response curves for H1299 and A431 cells treated with compound 7a for 24 h. *Significant diffe...
Reactions of 3-aryl-1-(trifluoromethyl)prop-2-yn-1-iminium salts with 1,3-dienes and styrenes
- Thomas Schneider,
- Michael Keim,
- Bianca Seitz and
- Gerhard Maas
Beilstein J. Org. Chem. 2020, 16, 2064–2072, doi:10.3762/bjoc.16.173
- propyn-1-iminium triflates 1a,b. Conditions: a) CH3CN, aqueous K2CO3, 15 min; b) 1. 1a + 2,3-dimethylbutadiene, dry CH2Cl2, 0 °C, 30 min, then rt, 2 h; 2. o-chloranil, CH2Cl2, rt, 20 h; 3. K2CO3, CH3CN/H2O, rt, 2 h; c) o-chloranil, dry CH2Cl2, rt, 22 h, then K2CO3, H2O; d) 1. dry CH3CN, rt, 1 h; 2. 50 °C
- , 22 h; 3. o-chloranil, CH2Cl2, rt, 12 h. Diels–Alder reaction of 1a and anthracene followed by an intramolecular SE(Ar) reaction. Reactions of propyn-1-iminium salt 1a with styrenes. A mechanistic proposal for the reaction of alkyne 1a with styrenes. Reaction of alkyne 1a with 1,2-dihydronaphthalene
Graphical Abstract
Scheme 1: Diels–Alder reaction of propyn-1-iminium salt 1a compared with the reported [29] reaction of 4-phenyl-1...
Scheme 2: Sequential Diels–Alder/intramolecular SE(Ar) reaction of propyn-1-iminium triflates 1a,b. Condition...
Scheme 3: Diels–Alder reaction of 1a and anthracene followed by an intramolecular SE(Ar) reaction.
Figure 1: Solid-state molecular structure of 11 (ORTEP plot).
Scheme 4: Reactions of propyn-1-iminium salt 1a with styrenes.
Figure 2: Solid-state molecular structure of 12c (ORTEP plot).
Figure 3: Solid-state molecular structure of 12d (ORTEP plot). Both the R and the S enantiomer are present in...
Scheme 5: A mechanistic proposal for the reaction of alkyne 1a with styrenes.
Scheme 6: Reaction of alkyne 1a with 1,2-dihydronaphthalene.
Scheme 7: Synthesis and solid-state molecular structure (ORTEP plot) of pentafulvene 19; selected bond distan...
Scheme 8: Proposed mechanistic pathway leading to fulvene 19.
The biomimetic synthesis of balsaminone A and ellagic acid via oxidative dimerization
- Sharna-kay Daley and
- Nadale Downer-Riley
Beilstein J. Org. Chem. 2020, 16, 2026–2031, doi:10.3762/bjoc.16.169
- be achieved in 57% yield over 5 steps. The synthesis of ellagic acid (5) on the other hand featured an o-chloranil-mediated dimerization of methyl gallate (15), which yielded the natural product in 48% yield over 5 steps, as reported by Tsuboi et al. (Scheme 3) [23]. Results and Discussion Biomimetic
Graphical Abstract
Figure 1: Selected natural products synthesized via oxidative dimerization.
Scheme 1: Proposed biosynthesis of balsaminone A (4) [19].
Scheme 2: Proposed biosynthesis of ellagic acid (5) [20].
Scheme 3: Previous syntheses of balsaminone A (4) [22] and ellagic acid (5) [23].
Scheme 4: Attempted synthesis of the biomimetic precursor 9. [O]: Act-C, K3[Fe(CN)6], or p-benzoquinone.
Scheme 5: Biomimetic synthesis of balsaminone A (4).
Scheme 6: Concise and efficient biomimetic synthesis of ellagic acid (5).
One hundred years of benzotropone chemistry
- Arif Dastan,
- Haydar Kilic and
- Nurullah Saracoglu
Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98
Graphical Abstract
Scheme 1: Tropone (1), tropolone (2) and their resonance structures.
Figure 1: Natural products containing a tropone nucleus.
Figure 2: Possible isomers 11–13 of benzotropone.
Scheme 2: Synthesis of benzotropones 11 and 12.
Scheme 3: Oxidation products of benzotropylium fluoroborate (16).
Scheme 4: Oxidation of 7-bromo-5H-benzo[7]annulene (22).
Scheme 5: Synthesis of 4,5-benzotropone (11) using o-phthalaldehyde (27).
Scheme 6: Synthesis of 4,5-benzotropone (11) starting from oxobenzonorbornadiene 31.
Scheme 7: Acid-catalyzed cleavage of oxo-bridge of 34.
Scheme 8: Synthesis of 4,5-benzotropone (11) from o-xylylene dibromide (38).
Scheme 9: Synthesis of 4,5-benzotropone (11) via the carbene adduct 41.
Scheme 10: Heck coupling strategy for the synthesis of 11.
Scheme 11: Synthesis of benzofulvalenes via carbonyl group of 4,5-benzotropone (11).
Figure 3: Some cycloheptatrienylium cations.
Scheme 12: Synthesis of condensation product 63 and its subsequent oxidative cyclization products.
Figure 4: A novel series of benzo[7]annulenes prepared from 4,5-benzotropone (11).
Scheme 13: Preparation of substituted benzo[7]annulene 72 using the Mukaiyama-Michael reaction.
Figure 5: Possible benzo[7]annulenylidenes 73–75.
Scheme 14: Thermal and photochemical decomposition of 7-diazo-7H-benzo[7]annulene (76) and the trapping of int...
Scheme 15: Synthesis of benzoheptafulvalene 86.
Scheme 16: Synthesis of 7-(diphenylmethylene)-7H-benzo[7]annulene (89).
Scheme 17: Reaction of 4,5-benzotropone (11) with dimethyl diazomethane.
Scheme 18: Synthesis of dihydrobenzomethoxyazocine 103.
Scheme 19: Synthesis and reducibility of benzo-homo-2-methoxyazocines.
Scheme 20: Synthesis of 4,5-benzohomotropones 104 and 115 from 4,5-benzotropones 11 and 113.
Scheme 21: A catalytic deuterogenation of 4,5-benzotropone (11) and synthesis of 5-monosubstituted benzo[7]ann...
Scheme 22: Synthesis of methyl benzo[7]annulenes 131 and 132.
Scheme 23: Ambident reactivity of halobenzo[7]annulenylium cations 133a/b.
Scheme 24: Preparation of benzo[7]annulenylidene–iron complexes 147.
Scheme 25: Synthesis of 1-ethynylbenzotropone (150) and the etheric compound 152 from 4,5-benzotropone (11) wi...
Scheme 26: Thermal decomposition of 4,5-benzotropone (11).
Scheme 27: Reaction of 4,5-benzotropone (11) with 1,2-ethanediol and 1,2-ethanedithiol.
Scheme 28: Conversions of 1-benzosuberone (162) to 2,3-benzotropone (12).
Scheme 29: Synthesis strategies for 2,3-bezotropone (12) using 1-benzosuberones.
Scheme 30: Oxidation-based synthesis of 2,3-benzotropone (12) via 1-benzosuberone (162).
Scheme 31: Synthesis of 2,3-benzotropone (12) from α-tetralone (171) via ring-expansion.
Scheme 32: Preparation of 2,3-benzotropone (12) by using of benzotropolone 174.
Figure 6: Benzoheptafulvenes as condensation products of 2,3-benzotropone (12).
Scheme 33: Conversion of 2,3-benzotropone (12) to tosylhydrazone salt 182 and gem-dichloride 187.
Figure 7: Benzohomoazocines 191–193 and benzoazocines 194–197.
Scheme 34: From 2,3-benzotropone (12) to carbonium ions 198–201.
Scheme 35: Cycloaddition reactions of 2,3-benzotropone (12).
Scheme 36: Reaction of 2,3-benzotropone (12) with various reagents and compounds.
Figure 8: 3,4-Benzotropone (13) and its resonance structure.
Scheme 37: Synthesis of 6,7-benzobicyclo[3.2.0]hepta-3,6-dien-2-one (230).
Figure 9: Photolysis and thermolysis products of 230.
Figure 10: Benzotropolones and their tautomeric structures.
Scheme 38: Synthesis strategies of 4,5-benzotropolone (238).
Scheme 39: Synthesis protocol for 2-hydroxy-4,5-benzotropone (238) using oxazole-benzo[7]annulene 247.
Figure 11: Some quinoxaline and pyrazine derivatives 254–256 prepared from 4,5-benzotropolone (238).
Scheme 40: Nitration product of 4,5-benzotropolone (238) and its isomerization to 1-nitro-naphthoic acid (259)....
Scheme 41: Synthesis protocol for 6-hydroxy-2,3-benzotropone (239) from benzosuberone (162).
Scheme 42: Various reactions via 6-hydroxy-2,3-benzotropone (239).
Scheme 43: Photoreaction of 6-hydroxy-2,3-benzotropone (239).
Scheme 44: Synthesis of 7-hydroxy-2,3-benzotropone (241) from benzosuberone (162).
Scheme 45: Synthesis strategy for 7-hydroxy-2,3-benzotropone (241) from ketone 276.
Scheme 46: Synthesis of 7-hydroxy-2,3-benzotropone (241) from β-naphthoquinone (280).
Scheme 47: Synthesis of 7-hydroxy-2,3-benzotropone (241) from bicyclic endoperoxide 213.
Scheme 48: Synthesis of 7-hydroxy-2,3-benzotropone (241) by ring-closing metathesis.
Figure 12: Various monosubstitution products 289–291 of 7-hydroxy-2,3-benzotropone (241).
Scheme 49: Reaction of 7-hydroxy-2,3-benzotropone (241) with various reagents.
Scheme 50: Synthesis of 4-hydroxy-2,3-benzotropones 174 and 304 from diketones 300/301.
Scheme 51: Catalytic hydrogenation of diketones 300 and 174.
Scheme 52: Synthesis of halo-benzotropones from alkoxy-naphthalenes 306, 307 and 310.
Figure 13: Unexpected byproducts 313–315 during synthesis of chlorobenzotropone 309.
Figure 14: Some halobenzotropones and their cycloadducts.
Scheme 53: Multisep synthesis of 2-chlorobenzotropone 309.
Scheme 54: A multistep synthesis of 2-bromo-benzotropone 26.
Scheme 55: A multistep synthesis of bromo-2,3-benzotropones 311 and 316.
Scheme 56: Oxidation reactions of 8-bromo-5H-benzo[7]annulene (329) with some oxidants.
Scheme 57: Synthesis of 2-bromo-4,5-benzotropone (26).
Scheme 58: Synthesis of 6-chloro-2,3-benzotropone (335) using LiCl and proposed intermediate 336.
Scheme 59: Reaction of 7-bromo-2,3-benzotropone (316) with methylamine.
Scheme 60: Reactions of bromo-2,3-benzotropones 26 and 311 with dimethylamine.
Scheme 61: Reactions of bromobenzotropones 311 and 26 with NaOMe.
Scheme 62: Reactions of bromobenzotropones 26 and 312 with t-BuOK in the presence of DPIBF.
Scheme 63: Cobalt-catalyzed reductive cross-couplings of 7-bromo-2,3-benzotropone (316) with cyclic α-bromo en...
Figure 15: Cycloadduct 357 and its di-π-methane rearrangement product 358.
Scheme 64: Catalytic hydrogenation of 2-chloro-4,5-benzotropone (311).
Scheme 65: Synthesis of dibromo-benzotropones from benzotropones.
Scheme 66: Bromination/dehydrobromination of benzosuberone (162).
Scheme 67: Some transformations of isomeric dibromo-benzotropones 261A/B.
Scheme 68: Transformations of benzotropolone 239B to halobenzotropolones 369–371.
Figure 16: Bromobenzotropolones 372–376 and 290 prepared via bromination/dehydrobromination strategy.
Scheme 69: Synthesis of some halobenzotropolones 289, 377 and 378.
Figure 17: Bromo-chloro-derivatives 379–381 prepared via chlorination.
Scheme 70: Synthesis of 7-iodo-3,4-benzotropolone (382).
Scheme 71: Hydrogenation of bromobenzotropolones 369 and 370.
Scheme 72: Debromination reactions of mono- and dibromides 290 and 375.
Figure 18: Nitratation and oxidation products of some halobenzotropolenes.
Scheme 73: Azo-coupling reactions of some halobenzotropolones 294, 375 and 378.
Figure 19: Four possible isomers of dibenzotropones 396–399.
Figure 20: Resonance structures of tribenzotropone (400).
Scheme 74: Two synthetic pathways for tribenzotropone (400).
Scheme 75: Synthesis of tribenzotropone (400) from dibenzotropone 399.
Scheme 76: Synthesis of tribenzotropone (400) from 9,10-phenanthraquinone (406).
Scheme 77: Synthesis of tribenzotropone (400) from trifluoromethyl-substituted arene 411.
Figure 21: Dibenzosuberone (414).
Figure 22: Reduction products 415 and 416 of tribenzotropone (400).
Figure 23: Structures of tribenzotropone dimethyl ketal 417 and 4-phenylfluorenone (412) and proposed intermed...
Figure 24: Structures of benzylidene- and methylene-9H-tribenzo[a,c,e][7]annulenes 419 and 420 and chiral phos...
Figure 25: Structures of tetracyclic alcohol 422, p-quinone methide 423 and cation 424.
Figure 26: Structures of host molecules 425–427.
Scheme 78: Synthesis of non-helical overcrowded derivatives syn/anti-431.
Figure 27: Hexabenzooctalene 432.
Figure 28: Structures of possible eight isomers 433–440 of naphthotropone.
Scheme 79: Synthesis of naphthotropone 437 starting from 1-phenylcycloheptene (441).
Scheme 80: Synthesis of 10-hydroxy-11H-cyclohepta[a]naphthalen-11-one (448) from diester 445.
Scheme 81: Synthesis of naphthotropone 433.
Scheme 82: Synthesis of naphthotropones 433 and 434 via cycloaddition reaction.
Scheme 83: Synthesis of naphthotropone 434 starting from 452.
Figure 29: Structures of tricarbonyl(tropone)irons 458, and possible cycloadducts 459.
Scheme 84: Synthesis of naphthotropone 436.
Scheme 85: Synthesis of precursor 465 for naphthotropone 435.
Scheme 86: Generation of naphthotropone 435 from 465.
Figure 30: Structures of tropylium cations 469 and 470.
Figure 31: Structures of tropylium ions 471+.BF4−, 472+.BF4−, and 473+.BF4−.
Scheme 87: Synthesis of tropylium ions 471+.BF4− and 479+.ClO4−.
Scheme 88: Synthesis of 1- and 2-methylanthracene (481 and 482) via carbene–carbene rearrangement.
Figure 32: Trapping products 488–490.
Scheme 89: Generation and chemistry of a naphthoannelated cycloheptatrienylidene-cycloheptatetraene intermedia...
Scheme 90: Proposed intermediates and reaction pathways for adduct 498.
Scheme 91: Exited-state intramolecular proton transfer of 505.
Figure 33: Benzoditropones 506 and 507.
Scheme 92: Synthesis of benzoditropone 506e.
Scheme 93: Synthetic approaches for dibenzotropone 507 via tropone (1).
Scheme 94: Formation mechanisms of benzoditropone 507 and 516 via 515.
Scheme 95: Synthesis of benzoditropones 525 and 526 from pyromellitic dianhydride (527).
Figure 34: Possible three benzocyclobutatropones 534–536.
Scheme 96: Synthesis of benzocyclobutatropones 534 and 539.
Scheme 97: Synthesis attempts for benzocyclobutatropone 545.
Scheme 98: Generation and trapping of symmetric benzocyclobutatropone 536.
Scheme 99: Synthesis of chloro-benzocyclobutatropone 552 and proposed mechanism of fluorenone derivatives.
Scheme 100: Synthesis of tropolone analogue 559.
Scheme 101: Synthesis of tropolones 561 and 562.
Figure 35: o/p-Tropoquinone rings (563 and 564) and benzotropoquinones (565–567).
Scheme 102: Synthesis of benzotropoquinone 566.
Scheme 103: Synthesis of benzotropoquinone 567 via a Diels–Alder reaction.
Figure 36: Products 575–577 through 1,2,3-benzotropoquinone hydrate 569.
Scheme 104: Structures 578–582 prepared from tropoquinone 567.
Figure 37: Two possible structures 583 and 584 for dibenzotropoquinone, and precursor compound 585 for 583.
Scheme 105: Synthesis of saddle-shaped ketone 592 using dibenzotropoquinone 584.
2-Hetaryl-1,3-tropolones based on five-membered nitrogen heterocycles: synthesis, structure and properties
- Yury A. Sayapin,
- Inna O. Tupaeva,
- Alexandra A. Kolodina,
- Eugeny A. Gusakov,
- Vitaly N. Komissarov,
- Igor V. Dorogan,
- Nadezhda I. Makarova,
- Anatoly V. Metelitsa,
- Valery V. Tkachev,
- Sergey M. Aldoshin and
- Vladimir I. Minkin
Beilstein J. Org. Chem. 2015, 11, 2179–2188, doi:10.3762/bjoc.11.236
- intramolecular N–H···O hydrogen bond. The mechanism of the formation of 1,3-tropolones in the reaction of methylene-active five-membered heterocycles with o-chloranil in acetic acid solution has been studied using density functional theory (DFT) methods. The reaction of 2-(2-benzoxa(thia)zolyl)-5,6,7-trichloro
- put forward by Schenk et al. [21] who reported on the preparation of a derivative of 1,2-tropolone 1 through condensation of 3,4,5,6-tetrachloro-1,2-benzoquinone (o-chloranil) with acetone. In the subsequent study of this reaction, the structure of its product analyzed with the use of two-dimensional
- NMR spectroscopy has been corrected and attributed to a derivative of 1,3-tropolone system 2 [17]. Later on this conclusion has been corroborated by the preparation of a series of 2-benzoyl-3-hydroxy-5,6,7-trichlorotropones 3 by the iron trichloride-catalyzed reaction of o-chloranil with acetophenones
Graphical Abstract
Scheme 1: 1,3-Tropolones 2–4 prepared by the reaction of o-chloranil with methylene active compounds.
Scheme 2: General scheme of the synthesis of 2-(2-hetaryl)-5,6,7-trichloro-1,3-tropolones 5 and 2-(2-hetaryl)...
Scheme 3: The mechanism for the formation of 5,6,7-trichloro-1,3-tropolones 5 and 4,5,6,7-tetrachloro-1,3-tro...
Figure 1: Molecular structure of 2-(3,3-dimethylindolyl)-5,6,7-trichloro-1,3-tropolone 5g. Thermal ellipsoids...
Figure 2: Molecular structure of 2-(5-chlorobenzothiazolyl)-4,5,6,7-tetrachloro-1,3-tropolone 6e. Thermal ell...
Scheme 4:
The fast prototropic N–H···O ![[Graphic 3]](/bjoc/content/inline/1860-5397-11-236-i8.png?max-width=637&scale=1.18182)
N···H–O equilibrium in solutions of 2-hetaryl-5,6,7-trichloro- and 4,...
Scheme 5: Two reaction paths for coupling 2-hetaryl-1,3-tropolones 5 and 6 with alcohols.
Figure 3: Molecular structure of 2-(3,3-dimethylindolyl)-5,7-dichloro-6-ethoxy-1,3-tropolone 13. Selected bon...
Figure 4: Molecular structure of 2-(2-ethoxycarbonyl-6-hydroxy-3,4,5-trichlorophenyl)benzoxazole 11b. Selecte...
Figure 5: Electronic absorption (1, 2), fluorescence emission (λexc = 350 nm) (3, 4) and fluorescence excitat...
Natural phenolic metabolites with anti-angiogenic properties – a review from the chemical point of view
- Qiu Sun,
- Jörg Heilmann and
- Burkhard König
Beilstein J. Org. Chem. 2015, 11, 249–264, doi:10.3762/bjoc.11.28
- H2SO4, gallic acid (4) was esterified to methyl gallate (5). The obtained ester 5 was first oxidatively coupled in the presence of o-chloranil, followed by reduction with Na2S2O4 to obtain the hexahydroxy biphenyl 6. Subsequent lactonization afforded the final product, ellagic acid (7), in high yield
- ) vanillin, 1,2,3,4-tetrahydroquinoline, HOAc, H3BO3, DMF, Δ, 4 h. Exemplary synthesis of MAC representatives. Reagents and conditions: (a) 40% KOH, EtOH, 5 °C; stirring 10 h, rt. X = C, N; R = OH, OMe, Cl, F. Synthesis of ellagic acid (7). Reagents and conditions: (a) H2SO4, CH3OH; (b) (1) o-chloranil, Et2O
Graphical Abstract
Figure 1: Structure of 4-hydroxybenzyl alcohol (HBA, 1).
Figure 2: Structure–activity relationship of curcumin analogs.
Scheme 1: Synthesis of curcumin (3). Reagents and conditions: (a) vanillin, 1,2,3,4-tetrahydroquinoline, HOAc...
Figure 3: Backbone and substitution of monocarbonyl analogs of curcumin (MACs) showing their structural diver...
Scheme 2: Exemplary synthesis of MAC representatives. Reagents and conditions: (a) 40% KOH, EtOH, 5 °C; stirr...
Scheme 3: Synthesis of ellagic acid (7). Reagents and conditions: (a) H2SO4, CH3OH; (b) (1) o-chloranil, Et2O...
Figure 4: Structure of resveratrol and its analogs.
Scheme 4: Synthesis of quinolone-substituted phenol 20. Reagents and conditions: (a) Ac2O, 2-hydroxybenzaldeh...
Scheme 5: Synthesis of quinolone-substituted phenol 23. Reagents and conditions: (a) Ac2O, 2-hydroxybenzaldeh...
Figure 5: Design of 4-amino-2-sulfanylphenol derivatives and their structure–activity relationship.
Scheme 6: Synthesis of 4-amino-2-sulfanylphenol derivatives. Reagents and conditions: (a) R1SO2Cl, pyridine, ...
Figure 6: Structures of two series of natural-like acylphloroglucinols.
Scheme 7: Synthesis of acylphloroglucinol derivatives 35–41. Reagents and conditions: (a) acyl chloride, AlCl3...
Scheme 8: Synthesis of acylphloroglucinol derivatives 43–51. Reagents and conditions: (a) isoprene, Amberlyst...
Figure 7: Analogs of (−)-EGCG for the prevention of oxidation and improvement of the bioavailability of the c...
Scheme 9: Synthesis of xanthohumol 58. Reagents and conditions: (a) MOMCl, diisopropylethylamine, CH2Cl2; (b)...
Scheme 10: Synthesis of genistein 60. Reagents and conditions: (a) 4-hydroxyphenylacetonitrile, anhydrous HCl,...
Scheme 11: Synthesis of fisetin (67) and quercetin (68). Reagents and conditions: (a) 3,4-dimethoxybenzaldehyd...
Figure 8: Structure of (2S)-7,2’,4’-trihydroxy-5-methoxy-8-(dimethylallyl)flavanone (69).
Gold(I)-catalysed one-pot synthesis of chromans using allylic alcohols and phenols
- Eloi Coutant,
- Paul C. Young,
- Graeme Barker and
- Ai-Lan Lee
Beilstein J. Org. Chem. 2013, 9, 1797–1806, doi:10.3762/bjoc.9.209
- dehydrative coupling strategy) [15][16]. To this end, the use of molybdenum catalyst CpMoCl(CO)3 together with an oxidant, o-chloranil, has been documented to catalyse the reaction of allylic alcohols with phenols to form chromans [17][18]. Strong and superacids have also been utilised in the synthesis of
Graphical Abstract
Scheme 1: Previous work on direct allylic etherification of allylic alcohols.
Figure 1: Initial side product with TMHQ.
Scheme 2: Proposed pathway.
Scheme 3: Control reactions.
Scheme 4: Reaction of 21 with added Brønsted acid co-catalyst.
Scheme 5: Suggested mechanism.
Intramolecular carbolithiation of N-allyl-ynamides: an efficient entry to 1,4-dihydropyridines and pyridines – application to a formal synthesis of sarizotan
- Wafa Gati,
- Mohamed M. Rammah,
- Mohamed B. Rammah and
- Gwilherm Evano
Beilstein J. Org. Chem. 2012, 8, 2214–2222, doi:10.3762/bjoc.8.250
- dihydropyridine to the corresponding pyridine by replacing the saturated aqueous ammonium chloride solution, used for the workup, by a combination of acetic acid and o-chloranil [41] was equally successful and provided the expected pyridine 6a in 81% yield (Scheme 2c). Synthesis of the starting N-allyl-ynamides
- , conditions A) or acetic acid and o-chloranil (Scheme 4, conditions B), yielding the corresponding 1,4-dihydropyridines 5 or pyridines 6, respectively. Results from these studies are collected in Scheme 4, yields being indicated only in the pyridine series due to the high sensitivity of the 1,4
- pyridine ring. To our delight, treatment of 14 under our optimized conditions (treatment with s-butyllithium and tetramethylethylenediamine in THF at −78 °C for one hour followed by addition of acetic acid and o-chloranil) smoothly promoted the anionic 6-endo-dig cyclization to the 3,5-disubstituted
Graphical Abstract
Scheme 1: Strategy for the synthesis of (1,4-dihydro)pyridines by deprotonation/intramolecular carbolithiatio...
Scheme 2: Feasibility of the deprotonation/intramolecular carbolithiation.
Scheme 3: Synthesis of the starting N-allyl-ynamides.
Scheme 4: Intramolecular carbolithiation of N-allyl-ynamides to 1,4-dihydropyridines and pyridines.
Scheme 5: 2,3-Disubstituted pyridines by trapping of the intermediate metallated 1,4-dihydropyridine.
Scheme 6: Formal synthesis of the anti-dyskinesia agent, 5-HT1A receptor agonist, dopamine D2 receptor ligand...
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
- catalytic FC benzylations using benzyl alcohols have been developed. These utilize for instance Cl2Si(OTf)2, Hf(OTf)4 [8], Yb(OTf)3, La(OTf)3 [9], InCl3 [10][11], NbCl5 [12], heterobimetallic Ir-Sn-catalysts [13][14], H-mont [15], [CpMoCl(CO)3]/o-chloranil [16], strong Brønsted acids [17][18][19] calix[6
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.
