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Search for "thiocyanate" in Full Text gives 36 result(s) in Beilstein Journal of Organic Chemistry.
Enabling technologies and green processes in cyclodextrin chemistry
- Giancarlo Cravotto,
- Marina Caporaso,
- Laszlo Jicsinszky and
- Katia Martina
Beilstein J. Org. Chem. 2016, 12, 278–294, doi:10.3762/bjoc.12.30
- . Monosubstituted CD derivative preparation Mono 6I-(p-toluenesulfonyl)-β-CD is the most popular of the CD derivatives because it is a key intermediate in the synthesis of important amino, azido, thio, thiocyanate and halo-derivatives. 6I-(p-toluenesulfonyl)-β-CD was efficiently prepared in an US-assisted procedure
Graphical Abstract
Figure 1: (a) Multihorn-flow US reactor, (b) Cavitational turbine, (c) Pilot-scale BM, (d) High-pressure MW r...
Figure 2: Trends in CD papers and CD use in green chemical processes.
Figure 3: Distribution of energy efficient methods in CD publications.
Figure 4: Document type dealing with CD chemistry under non-conventional techniques (conference proceedings a...
Figure 5: Document type dealing with sustainable technologies in CD publications.
Scheme 1: Synthesis of 6I-(p-toluenesulfonyl)-β-CD.
Scheme 2: Example of CuAAC with 6I-azido-6I-deoxy-β-CD and phenylacetylene.
Scheme 3: Synthesis of 6I-benzylureido-6I-deoxy-per-O-acetyl-β-CD.
Scheme 4: Synthesis of 3I-azido-3I-deoxy-altro-α, β- and γ-CD.
Scheme 5: Synthesis of 2-2’ bridged bis(β-CDs). Reaction conditions: 1) TBDMSCl, imidazole, dry pyridine, sti...
Scheme 6: Insoluble reticulated CD polymer.
Scheme 7: CD-HDI cross linked polymers.
Scheme 8: Derivatization of 6I-(p-toluenesulfonyl)-β-CD by tosyl displacement.
Scheme 9: Synthetic scheme for the preparation of heptakis(6-amino-6-deoxy)-β-CD, heptakis(6-deoxy-6-ureido)-...
Scheme 10: Structure of CD derivatives obtained via MW-assisted CuAAC.
Scheme 11: Preparation of SWCN CD-DOTA carrier.
Thiazole-induced rigidification in substituted dithieno-tetrathiafulvalene: the effect of planarisation on charge transport properties
- Rupert G. D. Taylor,
- Joseph Cameron,
- Iain A. Wright,
- Neil Thomson,
- Olena Avramchenko,
- Alexander L. Kanibolotsky,
- Anto R. Inigo,
- Tell Tuttle and
- Peter J. Skabara
Beilstein J. Org. Chem. 2015, 11, 1148–1154, doi:10.3762/bjoc.11.129
- Compounds 5 [15] and 6 [16] were prepared according to the relevant literature. Compound 4 was prepared in three steps starting with 1-bromooctan-2-one (Scheme 1). The substitution of the bromine atom for a thiocyanate group gave 1-thiocyanatooctan-2-one, which was subsequently cyclised under acidic
Graphical Abstract
Figure 1: Compounds 1–3.
Scheme 1: Synthesis of compound 4.
Scheme 2: Synthesis of compounds 1 and 2.
Figure 2: UV–vis absorption spectra of 10−5 M solutions of compounds 1 (black) and 2 (red) in dichloromethane....
Figure 3: Cyclic voltammograms showing the reduction (left) and oxidation (right) of compounds 1 (top) and 2 ...
Figure 4: Optimised structures of 1 (left), 2 (centre) and 3 (right).
Figure 5: Output characteristics of OFETs fabricated using compound 2 in CHCl3 with OTS (top) and PFBT/OTS (b...
Figure 6: AFM images of OFET devices fabricated using compound 2 in CHCl3 with OTS (left) and PFBT/OTS (right...
Advances in the synthesis of functionalised pyrrolotetrathiafulvalenes
- Luke J. O’Driscoll,
- Sissel S. Andersen,
- Marta V. Solano,
- Dan Bendixen,
- Morten Jensen,
- Troels Duedal,
- Jess Lycoops,
- Cornelia van der Pol,
- Rebecca E. Sørensen,
- Karina R. Larsen,
- Kenneth Myntman,
- Christian Henriksen,
- Stinne W. Hansen and
- Jan O. Jeppesen
Beilstein J. Org. Chem. 2015, 11, 1112–1122, doi:10.3762/bjoc.11.125
- . The reduction of the thiocyanate moieties with LiAlH4 afforded the air-sensitive intermediate 18 (not characterised), which was treated with 1,1’-carbonyldiimidazole to afford 7, in 83% yield over the two steps. Preparation of functionalised MPTTFs and BPTTFs Coupling reactions Pyrrole-annelated TTF
Graphical Abstract
Figure 1: The sequential, reversible oxidation of TTF (1) to its stable radical cation (2) and dication (3) s...
Figure 2: Structures and possible substitution positions of MPTTFs (4) and BPTTFs (5).
Scheme 1: Large-scale synthesis of 6. Reagents and conditions: a) PhMe, reflux, 19 h, 74%; b) LiBr, NaBH4, TH...
Scheme 2: Preparation of 7. Reagents and conditions: a) TsCl, Et3N, DMAP, MeCN, rt → reflux, 3.5 h, 82%; b) (...
Scheme 3: Homo and cross-coupling reactions of 6 or 7 afford BPTTFs and MPTTFs, respectively. Reagents and co...
Scheme 4: Deprotection and methylation of cyanoethyl-protected thiol moieties on MPTTFs as reported by Jeppes...
Scheme 5: Deprotection and alkylation of cyanoethyl-protected thiol moieties on MPTTFs using CsOH·H2O or DBU....
Scheme 6: Deprotection and N-arylation of tosylated MPTTFs. Reagents and conditions: a) NaOMe, THF, MeOH, ref...
Scheme 7: Deprotection and N,N-diarylation of tosylated BPTTFs. Reagents and conditions: a) NaOMe, THF, MeOH,...
Synthesis of nanodiamond derivatives carrying amino functions and quantification by a modified Kaiser test
- Gerald Jarre,
- Steffen Heyer,
- Elisabeth Memmel,
- Thomas Meinhardt and
- Anke Krueger
Beilstein J. Org. Chem. 2014, 10, 2729–2737, doi:10.3762/bjoc.10.288
- . This system has been successfully used for the functionalization of fullerenes [15]. The precursor 8 was synthesized according to Martinez et al. starting from cyclobutanone and methyl thiocyanate [16]. The cyclobutene ring opens at temperatures around 190 °C and the ortho-quinodimethane is formed in
Graphical Abstract
Scheme 1: Synthesis of nanodiamond derivatives carrying primary amino groups. a) Δ, b) 18-crown-6, KI, c) BH3...
Figure 1: FTIR-spectra of annealed nanodiamond 2 (a), nitrile 4 (b) and amine 5 (c). As can be seen from the ...
Figure 2: FTIR spectra (left) of compounds 2 (a), 9 (b), 10 (c) and 11 (d). The formation of the sulfone grou...
Figure 3: Modified Kaiser test. a) Left: control, right: positive result; b) left: control, control with prem...
Atherton–Todd reaction: mechanism, scope and applications
- Stéphanie S. Le Corre,
- Mathieu Berchel,
- Hélène Couthon-Gourvès,
- Jean-Pierre Haelters and
- Paul-Alain Jaffrès
Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117
- and purification on silica gel finally afforded the β-alkynyl-enolphosphate in 61–75% yield [58]. Azide, nitrile and thiocyanate were three other nucleophilic species used to produce pseudohalogenated phosphorus species by the AT reaction. Among them, the commercially available diphenyl
Graphical Abstract
Scheme 1: Pioneer works of Atherton, Openshaw and Todd reporting on the synthesis of phosphoramidate starting...
Scheme 2: Mechanisms 1 (i) and 2 (ii) suggested by Atherton and Todd in 1945; adapted from [1].
Scheme 3: Two reaction pathways (i and ii) to produce chlorophosphate 2. Charge-transfer complex observed whe...
Scheme 4: Mechanism of the Atherton–Todd reaction with dimethylphosphite according to Roundhill et al. (adapt...
Scheme 5: Synthesis of dialkyl phosphate from dialkyl phosphite (i) and identification of chloro- and bromoph...
Scheme 6: Synthesis of chiral phosphoramidate with trichloromethylphosphonate as the suggested intermediate (...
Scheme 7: Selection of results that address the question of the stereochemistry of the AT reaction (adapted f...
Scheme 8: Synthesis of phenoxy spirophosphorane by the AT reaction (adapted from [34]).
Scheme 9: Suggested mechanism of the Atherton–Todd reaction, (i) and (ii) formation of chlorophosphate with a...
Scheme 10: AT reaction in biphasic conditions (adapted from [38]).
Scheme 11: AT reaction with iodoform as halide source (adapted from [37]).
Scheme 12: AT reaction with phenol at low temperature in the presence of DMAP (adapted from [40]).
Scheme 13: Synthesis of a triphosphate by the AT reaction starting with the preparation of chlorophosphate (ad...
Scheme 14: AT reaction with sulfonamide (adapted from [42]).
Scheme 15: Synthesis of a styrylphosphoramidate starting from the corresponding aniline (adapted from [43]).
Scheme 16: Use of hydrazine as nucleophile in AT reactions (adapted from [48]).
Scheme 17: AT reaction with phenol as a nucleophilic species; synthesis of dioleyl phosphate-substituted couma...
Scheme 18: Synthesis of β-alkynyl-enolphosphate from allenylketone with AT reaction (adapted from [58]).
Scheme 19: Synthesis of pseudohalide phosphate by using AT reaction (adapted from [67]).
Scheme 20: AT reaction with hydrospirophosphorane with insertion of CO2 in the product (adapted from [69]).
Scheme 21: AT reaction with diaryl phosphite (adapted from [70]).
Scheme 22: AT reaction with O-alkyl phosphonite (adapted from [71]).
Scheme 23: Use of phosphinous acid in AT reactions (adapted from [72]).
Scheme 24: AT reaction with secondary phosphinethiooxide (adapted from [76]).
Scheme 25: Use of H-phosphonothioate in the AT reaction (adapted from [78]).
Scheme 26: AT-like reaction with CuI as catalyst and without halide source (adapted from [80]).
Scheme 27: Reduction of phenols after activation as phosphate derivatives (adapted from [81] i ; [82], ii; and [83], iii).
Scheme 28: Synthesis of medium and large-sized nitrogen-containing heterocycles (adapted from [85]).
Scheme 29: Synthesis of arylstannane from aryl phosphate prepared by an AT reaction (adapted from [86]).
Scheme 30: Synthesis and use of aryl dialkyl phosphate for the synthesis of biaryl derivatives (adapted from [89])....
Scheme 31: Synthesis of aryl dialkyl phosphate by an AT reaction from phenol and subsequent rearrangement yiel...
Scheme 32: Selected chiral phosphoramidates used as organocatalyst; i) chiral phosphoramidate used in the pion...
Scheme 33: Determination of ee of H-phosphinate by the application of the AT reaction with a chiral amine (ada...
Scheme 34: Chemical structure of selected flame retardants synthesized by AT reactions; (BDE: polybrominated d...
Scheme 35: Transformation of DOPO (i) and synthesis of polyphosphonate (ii) by the AT reaction (adapted from [117] ...
Scheme 36: Synthesis of lipophosphite (bisoleyl phosphite) and cationic lipophosphoramidate with an AT reactio...
Scheme 37: Use of AT reactions to produce cationic lipids characterized by a trimethylphosphonium, trimethylar...
Scheme 38: Cationic lipid synthesized by the AT reaction illustrating the variation of the structure of the li...
Scheme 39: Helper lipids for nucleic acid delivery synthesized with the AT reaction (adapted from [130]).
Scheme 40: AT reaction used to produce red/ox-sensitive cationic lipids (adapted from [135]).
Scheme 41: Alkyne and azide-functionalized phosphoramidate synthesized by AT reactions,(i); illustration of so...
Scheme 42: Cationic lipids exhibiting bactericidal action – arrows indicate the bond formed by the AT reaction...
Scheme 43: β-Cyclodextrin-based lipophosphoramidates (adapted from [138]).
Scheme 44: Polyphosphate functionalized by an AT reaction (adapted from [139]).
Scheme 45: Synthesis of zwitterionic phosphocholine-bound chitosan (adapted from [142]).
Scheme 46: Synthesis of AZT-based prodrug via an AT reaction (adapted from [143]).
Use of 3-[18F]fluoropropanesulfonyl chloride as a prosthetic agent for the radiolabelling of amines: Investigation of precursor molecules, labelling conditions and enzymatic stability of the corresponding sulfonamides
- Reik Löser,
- Steffen Fischer,
- Achim Hiller,
- Martin Köckerling,
- Uta Funke,
- Aurélie Maisonial,
- Peter Brust and
- Jörg Steinbach
Beilstein J. Org. Chem. 2013, 9, 1002–1011, doi:10.3762/bjoc.9.115
- Chemistry Group, Albert-Einstein-Straße 3a, 18059 Rostock, Germany 10.3762/bjoc.9.115 Abstract 3-[18F]Fluoropropanesulfonyl chloride, a recently proposed prosthetic agent for fluorine-18 labelling, was prepared in a two-step radiosynthesis via 3-[18F]fluoropropyl thiocyanate as an intermediate. Two
- of 3-[18F]fluoropropyl thiocyanate to the corresponding sulfonyl chloride with the potential for automation have been identified. The reaction of 3-[18F]fluoropropanesulfonyl chloride with eight different aliphatic and aromatic amines was investigated and the identity of the resulting 18F-labelled
- are easily accessible, sufficiently stable to oxidation, and nonhygroscopic. Li et al. [18] decided to use a propyl spacer between the fluorine-18 atom and the thiocyanate moiety as radiofluorination by nucleophilic substitution proceeds easier at aliphatic than at aromatic electrophilic centres. In
Graphical Abstract
Figure 1: Selection of prosthetic agents for 18F-labelling via acylation.
Scheme 1: Synthesis of radiofluorination precursors 3 and 4. Reagents and conditions: (a) KSCN, CH3OH, reflux...
Scheme 2: Synthesis of 3-fluoropropanesulfonamide 11 via intermediary 3-fluoropropanesulfonyl chloride (10). ...
Scheme 3: Synthesis of 3-fluoropropanesulfonamides 12–18. Reagents and conditions: (a) triethylamine (TEA), CH...
Figure 2: (A) View of the molecular structure of sulfonamide 18 with atom labelling scheme. Displacement elli...
Figure 3: Dependence of the labelling yields of [18F]9 on the precursor amount. Reactions of tosylate 3 and n...
Figure 4: Time course of the distillation of 3-[18F]fluoropropyl thiocyanate ([18F]9) in the argon stream. Fo...
Scheme 4: Radiosynthesis of 3-[18F]fluoropropanesulfonamides [18F]11–[18F]18. Reagents and conditions: (a) [18...
Figure 5: Radio-HPLC chromatograms for the reaction of [18F]10 with (A) 4-fluoroaniline in the absence and pr...
Figure 6: Time course of the carboxylesterase-catalysed degradation of 3-fluoropropansulfonamide 17 (red) and...
The chemistry of bisallenes
- Henning Hopf and
- Georgios Markopoulos
Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225
Graphical Abstract
Figure 1: Loschmidt’s structure proposal for benzene (1) (Scheme 181 from [3]) and the corresponding modern stru...
Figure 2: The first isolated bisallenes.
Figure 3: Carbon skeletons of selected bisallenes discussed in this review.
Scheme 1: The preparation of 1,2,4,5-hexatetraene (2).
Scheme 2: The preparation of a conjugated bisallene by the DMS-protocol.
Scheme 3: Preparation of the 3-deuterio- and 3,4-dideuterio derivatives of 24.
Scheme 4: A versatile method to prepare alkylated conjugated bisallenes and other allenes.
Scheme 5: A preparation of 3,4-dimethyl-1,2,4,5-hexatetraene (38).
Scheme 6: A (C6 + 0)-approach to 1,2,4,5-hexatetraene (2).
Scheme 7: The preparation of a fully alkylated bisallenes from a 2,4-hexadiyne-1,6-diol diacetate.
Scheme 8: The preparation of the first phenyl-substituted conjugated bisallenes 3 and 4.
Scheme 9: Selective hydrogenation of [5]cumulenes to conjugated bisallenes: another (C6 + 0)-route.
Scheme 10: Aryl-substituted conjugated bisallenes by a (C3 + C3)-approach.
Scheme 11: Hexaphenyl-1,2,4,5-hexatetraene (59) by a (C3 + C3)-approach.
Scheme 12: An allenation route to conjugated bisallenes.
Scheme 13: The preparation of 3,4-difunctionalized conjugated bisallenes.
Scheme 14: Problems during the preparation of sulfur-substituted conjugated bisallenes.
Scheme 15: The preparation of 3,4-dibromo bisallenes.
Scheme 16: Generation of allenolates by an oxy-Cope rearrangement.
Scheme 17: A linear trimerization of alkynes to conjugated bisallenes: a (C2 + C2 + C2)-protocol.
Scheme 18: Preparation of a TMS-substituted conjugated bisallene by a C3-dimerization route.
Scheme 19: A bis(trimethylsilyl)bisallene by a C3-coupling protocol.
Scheme 20: The rearrangement of highly substituted benzene derivatives into their conjugated bisallenic isomer...
Scheme 21: From fully substituted benzene derivatives to fully substituted bisallenes.
Scheme 22: From a bicyclopropenyl to a conjugated bisallene derivative.
Scheme 23: The conversion of a bismethylenecyclobutene into a conjugated bisallene.
Scheme 24: The preparation of monofunctionalized bisallenes.
Scheme 25: Preparation of bisallene diols and their cyclization to dihydrofurans.
Scheme 26: A 3,4-difunctionalized conjugated bisallene by a C3-coupling process.
Scheme 27: Preparation of a bisallenic diketone by a coupling reaction.
Scheme 28: Sulfur and selenium-substituted bisallenes by a [2.3]sigmatropic rearrangement.
Scheme 29: The biallenylation of azetidinones.
Scheme 30: The preparation of a fully ferrocenylated conjugated bisallene.
Scheme 31: The first isomerization of a 1,5-hexadiyne to a 1,2,4,5-hexatetraene.
Scheme 32: The preparation of alkynyl-substituted bisallenes by a C3-dimerization protocol.
Scheme 33: Preparation of another completely ferrocenylated bisallene.
Scheme 34: The cyclization of 1,5-hexadiyne (129) to 3,4-bismethylenecyclobutene (130) via 1,2,4,5-hexatetraen...
Scheme 35: Stereochemistry of the thermal cyclization of bisallenes to bismethylenecyclobutenes.
Scheme 36: Bisallene→bismethylenecyclobutene ring closures in the solid state.
Scheme 37: A bisallene cyclization/dimerization reaction.
Scheme 38: A selection of Diels–Alder additions of 1,2,4,5-hexatetraene with various double-bond dienophiles.
Scheme 39: The stereochemistry of the [2 + 4] cycloaddition to conjugated bisallenes.
Scheme 40: Preparation of azetidinone derivatives from conjugated bisallenes.
Scheme 41: Cycloaddition of heterodienophiles to a conjugated bisallene.
Scheme 42: Addition of triple-bond dienophiles to conjugated bisallenes.
Scheme 43: Sulfur dioxide addition to conjugated bisallenes.
Scheme 44: The addition of a germylene to a conjugated bisallene.
Scheme 45: Trapping of conjugated bisallenes with phosphinidenes.
Scheme 46: The cyclopropanantion of 1,2,4,5-hexatetraene (2).
Scheme 47: Photochemical reactions involving conjugated bisallenes.
Scheme 48: Base-catalyzed isomerizations of conjugated bisallenes.
Scheme 49: Ionic additions to a conjugated bisallene.
Scheme 50: Oxidation reactions of a conjugated bisallene.
Scheme 51: The mechanism of oxidation of the bisallene 24.
Scheme 52: CuCl-catalyzed cyclization of 1,2,4,5-hexatetraene (2).
Scheme 53: The conversion of conjugated bisallenes into cyclopentenones.
Scheme 54: Oligomerization of a conjugated bisallene by nickel catalysts.
Scheme 55: Generation of 1,2,5,6-heptatetraene (229) as a reaction intermediate.
Scheme 56: The preparation of a stable derivative of 1,2,5,6-heptatetraene.
Scheme 57: A bisallene with a carbonyl group as a spacer element.
Scheme 58: The first preparation of 1,2,6,7-octatetraene (242).
Scheme 59: Preparation of 1,2,6,7-octatetraenes by (C4 + C4)-coupling of enynes.
Scheme 60: Preparation of 1,2,6,7-octatetraenes by (C4 + C4)-coupling of homoallenyl bromides.
Scheme 61: Preparation of 1,2,6,7-octatetraenes by alkylation of propargylic substrates.
Scheme 62: Preparation of two highly functionalized 1,2,6,7-octatetraenes.
Scheme 63: Preparation of several higher α,ω-bisallenes.
Scheme 64: Preparation of different alkyl derivatives of α,ω-bisallenes.
Scheme 65: The preparation of functionalized 1,2,7,8-nonatetraene derivatives.
Scheme 66: Preparation of functionalized α,ω-bisallenes.
Scheme 67: The preparation of an α,ω-bisallene by direct homologation of an α,ω-bisalkyne.
Scheme 68: The gas-phase pyrolysis of 4,4-dimethyl-1,2,5,6-heptatetraene (237).
Scheme 69: Gas-phase pyrolysis of 1,2,6,7-octatetraene (242).
Scheme 70: The cyclopropanation of 1,2,6,7-octatetraene (242).
Scheme 71: Intramolecular cyclization of 1,2,6,7-octatetraene derivatives.
Scheme 72: The gas-phase pyrolysis of 1,2,7,8-nonatetraene (265) and 1,2,8,9-decatetraene (266).
Scheme 73: Rh-catalyzed cyclization of a functionalized 1,2,7,8-nonatetraene.
Scheme 74: A triple cyclization involving two different allenic substrates.
Scheme 75: Bicyclization of keto derivatives of 1,2,7,8-nonatetraene.
Scheme 76: The preparation of complex organic compounds from functionalized bisallenes.
Scheme 77: Cycloisomerization of an α,ω-bisallene containing a C9 tether.
Scheme 78: Organoborane polymers from α,ω-bisallenes.
Scheme 79: Preparation of trans- (337) and cis-1,2,4,6,7-octapentaene (341).
Scheme 80: The preparation of 4-methylene-1,2,5,6-heptatetraene (349).
Scheme 81: The preparation of acetylenic bisallenes.
Scheme 82: The preparation of derivatives of hydrocarbon 351.
Scheme 83: The construction of macrocyclic alleno-acetylenes.
Scheme 84: Preparation and reactions of 4,5-bismethylene-1,2,6,7-octatetraene (365).
Scheme 85: Preparation of 1,2-bis(propadienyl)benzene (370).
Scheme 86: The preparation of 1,4-bis(propadienyl)benzene (376).
Scheme 87: The preparation of aromatic and heteroaromatic bisallenes by metal-mediated coupling reactions.
Scheme 88: Double cyclization of an aromatic bisallene.
Scheme 89: Preparation of an allenic [15]paracyclophane by a ring-closing metathesis reaction of an aromatic α...
Scheme 90: Preparation of a macrocyclic ring system containing 1,4-bis(propadienyl)benzene units.
Scheme 91: Preparation of copolymers from 1,4-bis(propadienyl)benzene (376).
Scheme 92: A boration/copolymerization sequence of an aromatic bisallene and an aromatic bisacetylene.
Scheme 93: Formation of a layered aromatic bisallene.
Figure 4: The first members of the semicyclic bisallene series.
Scheme 94: Preparation of the first bis(vinylidene)cyclobutane derivative.
Scheme 95: Dimerization of strain-activated cumulenes to bis(vinylidene)cyclobutanes.
Scheme 96: Photodimerization of two fully substituted butatrienes in the solid state.
Scheme 97: Preparation of the two parent bis(vinylidene)cyclobutanes.
Scheme 98: The preparation of 1,3-bis(vinylidene)cyclopentane and its thermal isomerization.
Scheme 99: The preparation of the isomeric bis(vinylidene)cyclohexanes.
Scheme 100: Bi- and tricyclic conjugated bisallenes.
Scheme 101: A selection of polycyclic bisallenes.
Scheme 102: The first endocyclic bisallenes.
Figure 5: The stereochemistry of 1,2,6,7-cyclodecatetraene.
Scheme 103: The preparation of several endocyclic bisallenes.
Scheme 104: Synthesis of diastereomeric derivatives of 1,2,6,7-cyclodecatetraene.
Scheme 105: Preparation of a derivative of 1,2,8,9-cyclotetradecatetraene.
Scheme 106: The preparation of keto derivatives of cyclic bisallenes.
Scheme 107: The preparation of cyclic biscumulenic ring systems.
Scheme 108: Cyclic bisallenes in natural- and non-natural-product chemistry.
Scheme 109: The preparation of iron carbonyl complexes from cyclic bisallenes.
Figure 6: A selection of unknown exocyclic bisallenes that should have interesting chemical properties.
Scheme 110: The thermal isomerization of 1,2-diethynylcyclopropanes and -cyclobutanes.
Scheme 111: Intermediate generation of a cyclooctapentaene.
Scheme 112: Attempted preparation of a cyclodecahexaene.
Scheme 113: The thermal isomerization of 1,5,9-cyclododecatriyne (511) into [6]radialene (514).
Scheme 114: An isomerization involving a diketone derived from a conjugated bisallene.
Scheme 115: Typical reaction modes of heteroorganic bisallenes.
Scheme 116: Generation and thermal behavior of acyclic hetero-organic bisallenes.
Scheme 117: Generation of bis(propadienyl)thioether.
Scheme 118: The preparation of a bisallenic sulfone and its thermal isomerization.
Scheme 119: Bromination of the bisallenic sulfone 535.
Scheme 120: Metalation/hydrolysis of the bisallenic sulfone 535.
Scheme 121: Aromatic compounds from hetero bisallenes.
Scheme 122: Isomerization/cyclization of bispropargylic ethers.
Scheme 123: The preparation of novel aromatic systems by base-catalyzed isomerization of bispropargyl ethers.
Scheme 124: The isomerization of bisacetylenic thioethers to bicyclic thiophenes.
Scheme 125: Aromatization of macrocyclic bispropargylic sulfides.
Scheme 126: Preparation of ansa-compounds from macrocyclic bispropargyl thioethers.
Scheme 127: Alternate route for cyclization of a heterorganic bisallene.
Scheme 128: Multiple isomerization/cyclization of “double” bispropargylic thioethers.
Scheme 129: Preparation of a bisallenyl disulfide and its subsequent bicyclization.
Scheme 130: Thermal cyclization of a bisallenyl thiosulfonate.
Scheme 131: Some reactions of heteroorganic bisallenes with two sulfur atoms.
Scheme 132: Further methods for the preparation of heteroorganic bisallenes.
Scheme 133: Cyclization reactions of heteroorganic bisallenes.
Scheme 134: Thermal cycloadditions of bisallenic tertiary amines.
Scheme 135: Cyclization of a bisallenic tertiary amine in the presence of a transition-metal catalyst.
Scheme 136: A Pauson–Khand reaction of a bisallenic ether.
Scheme 137: Formation of a 2:1adduct from two allenic substrates.
Scheme 138: A ring-forming silastannylation of a bisallenic tertiary amine.
Scheme 139: A three-component cyclization involving a heterorganic bisallene.
Scheme 140: Atom-economic construction of a complex organic framework from a heterorganic α,ω-bisallene.
Nano copper oxide catalyzed synthesis of symmetrical diaryl sulfides under ligand free conditions
- K. Harsha Vardhan Reddy,
- V. Prakash Reddy,
- A. Ashwan Kumar,
- G. Kranthi and
- Y.V.D. Nageswar
Beilstein J. Org. Chem. 2011, 7, 886–891, doi:10.3762/bjoc.7.101
- K. Harsha Vardhan Reddy V. Prakash Reddy A. Ashwan Kumar G. Kranthi Y.V.D. Nageswar Organic Chemistry Divison-I, Indian Institute of Chemical Technology, Hyderabad-500 607, India 10.3762/bjoc.7.101 Abstract Potassium thiocyanate acts as an efficient sulfur surrogate in C–S cross-coupling
- reactions mediated by recyclable copper oxide nanoparticles under ligand free conditions. This protocol avoids foul smelling thiols, for the synthesis of a variety of symmetrical diaryl sulfides, via the cross-coupling of different aryl halides with potassium thiocyanate, affording corresponding products in
- moderate to excellent yields. Keywords: aryl halides; aryl sulfides; copper oxide; cross-coupling; ligand free; potassium thiocyanate; recyclable; Introduction After the discovery of copper-promoted Ullmann reaction [1][2][3] for the construction of carbon-hetero atom bonds, several protocols have been
Graphical Abstract
Scheme 1: Synthesis of symmetrical aryl sulfides catalyzed by copper oxide nanoparticles.
An overview of the key routes to the best selling 5-membered ring heterocyclic pharmaceuticals
- Marcus Baumann,
- Ian R. Baxendale,
- Steven V. Ley and
- Nikzad Nikbin
Beilstein J. Org. Chem. 2011, 7, 442–495, doi:10.3762/bjoc.7.57
Graphical Abstract
Figure 1: Structures of atorvastatin and other commercial statins.
Figure 2: Structure of compactin.
Scheme 1: Synthesis of pentasubstituted pyrroles.
Scheme 2: [3 + 2] Cycloaddition to prepare 5-isopropylpyrroles.
Scheme 3: Regiospecific [3 + 2] cycloaddition to prepare the pyrrole scaffold.
Scheme 4: Formation of the pyrrole core of atorvastatin via [3 + 2] cycloaddition.
Scheme 5: Formation of pyrrole 33 via the Paal–Knorr reaction.
Scheme 6: Convergent synthesis towards atorvastatin.
Figure 3: Binding pocket of sunitinib in the TRK KIT.
Scheme 7: Synthesis of sunitinib.
Scheme 8: Alternative synthesis of sunitinib.
Scheme 9: Key steps in the syntheses of sumatriptan and zolmitriptan.
Scheme 10: Introduction of the N,N-dimethylaminoethyl side chain.
Scheme 11: Japp–Klingemann reaction in the synthesis of sumatriptan.
Scheme 12: Synthesis of the intermediate sulfonyl chlorides 62 and 63.
Scheme 13: Alternative introduction of the sulfonamide.
Scheme 14: Negishi-type coupling to benzylic sulfonamides.
Scheme 15: Heck reaction used to introduce the sulfonamide side chain of naratriptan.
Scheme 16: Synthesis of the oxazolinone appendage of zolmitriptan.
Scheme 17: Grandberg indole synthesis used in the preparation of rizatriptan.
Scheme 18: Improved synthesis of rizatriptan.
Scheme 19: Larock-type synthesis of rizatriptan.
Scheme 20: Synthesis of eletriptan.
Scheme 21: Heck coupling for the indole system in eletriptan.
Scheme 22: Attempted Fischer indole synthesis of elatriptan.
Scheme 23: Successful Fischer indole synthesis for eletriptan.
Scheme 24: Mechanistic rationale for the Bischler–Möhlau reaction.
Scheme 25: Bischler-type indole synthesis used in the fluvastatin sodium synthesis.
Scheme 26: Palladium-mediated synthesis of ondansetron.
Scheme 27: Fischer indole synthesis of ondansetron.
Scheme 28: Optimised Pictet–Spengler reaction towards tadalafil.
Figure 4: Structures of carvedilol 136 and propranolol 137.
Scheme 29: Synthesis of the carbazole core of carvedilol.
Scheme 30: Alternative syntheses of 4-hydroxy-9H-carbazole.
Scheme 31: Convergent synthesis of etodolac.
Scheme 32: Alternative synthesis of etodolac.
Figure 5: Structures of imidazole-containing drugs.
Scheme 33: Synthesis of functionalised imidazoles towards losartan.
Scheme 34: Direct synthesis of the chlorinated imidazole in losartan.
Scheme 35: Synthesis of trisubstituted imidazoles.
Scheme 36: Preparation of the imidazole ring in olmesartan.
Scheme 37: Synthesis of ondansetron.
Scheme 38: Alternative route to ondansetron and its analogues.
Scheme 39: Proton pump inhibitors and synthesis of esomeprazole.
Scheme 40: Synthesis of benzimidazole core pantoprazole.
Figure 6: Structure of rabeprazole 194.
Scheme 41: Synthesis of candesartan.
Scheme 42: Alternative access to the candesartan key intermediate 216.
Scheme 43: .Medicinal chemistry route to telmisartan.
Scheme 44: Improved synthesis of telmisartan.
Scheme 45: Synthesis of zolpidem.
Scheme 46: Copper-catalysed 3-component coupling towards zolpidem.
Figure 7: Structure of celecoxib.
Scheme 47: Preparation of celecoxib.
Scheme 48: Alternative synthesis of celecoxib.
Scheme 49: Regioselective access to celecoxib.
Scheme 50: Synthesis of pazopanib.
Scheme 51: Syntheses of anastrozole, rizatriptan and letrozole.
Scheme 52: Regioselective synthesis of anastrozole.
Scheme 53: Triazine-mediated triazole formation towards anastrozole.
Scheme 54: Alternative routes to 1,2,4-triazoles.
Scheme 55: Initial synthetic route to sitagliptin.
Figure 8: Binding of sitagliptin within DPP-IV.
Scheme 56: The process route to sitagliptin key intermediate 280.
Scheme 57: Synthesis of maraviroc.
Scheme 58: Synthesis of alprazolam.
Scheme 59: The use of N-nitrosoamidine derivatives in the preparation of fused benzodiazepines.
Figure 9: Structures of itraconazole, ravuconazole and voriconazole.
Scheme 60: Synthesis of itraconazole.
Scheme 61: Synthesis of rufinamide.
Scheme 62: Representative tetrazole formation in valsartan.
Figure 10: Structure of tetrazole containing olmesartan, candesartan and irbesartan.
Scheme 63: Early stage introduction of the tetrazole in losartan.
Scheme 64: Synthesis of cilostazol.
Figure 11: Structure of cefdinir.
Scheme 65: Semi-synthesis of cefdinir.
Scheme 66: Thiazole syntheses towards ritonavir.
Scheme 67: Synthesis towards pramipexole.
Scheme 68: Alternative route to pramipexole.
Scheme 69: Synthesis of famotidine.
Scheme 70: Efficient synthesis of the hyperuricemic febuxostat.
Scheme 71: Synthesis of ziprasidone.
Figure 12: Structure of mometasone.
Scheme 72: Industrial access to 2-furoic acid present in mometasone.
Scheme 73: Synthesis of ranitidine from furfuryl alcohol.
Scheme 74: Synthesis of nitrofurantoin.
Scheme 75: Synthesis of benzofuran.
Scheme 76: Synthesis of amiodarone.
Scheme 77: Synthesis of raloxifene.
Scheme 78: Alternative access to the benzo[b]thiophene core of raloxifene.
Scheme 79: Gewald reaction in the synthesis of olanzapine.
Scheme 80: Alternative synthesis of olanzapine.
Figure 13: Access to simple thiophene-containing drugs.
Scheme 81: Synthesis of clopidogrel.
Scheme 82: Pictet–Spengler reaction in the preparation of tetrahydrothieno[3,2-c]pyridine (422).
Scheme 83: Alternative synthesis of key intermediate 422.
Figure 14: Co-crystal structures of timolol (left) and carazolol (right) in the β-adrenergic receptor.
Scheme 84: Synthesis of timolol.
Scheme 85: Synthesis of tizanidine 440.
Scheme 86: Synthesis of leflunomide.
Scheme 87: Synthesis of sulfamethoxazole.
Scheme 88: Synthesis of risperidone.
Figure 15: Relative abundance of selected transformations.
Figure 16: The abundance of heterocycles within top 200 drugs (5-membered rings).
Kinetics and mechanism of vanadium catalysed asymmetric cyanohydrin synthesis in propylene carbonate
- Michael North and
- Marta Omedes-Pujol
Beilstein J. Org. Chem. 2010, 6, 1043–1055, doi:10.3762/bjoc.6.119
- propylene carbonate under identical reaction conditions to those used in dichloromethane can be explained in two ways. It is possible that in propylene carbonate, some addition of TMSCN to aldehydes occurs exclusively by Lewis base catalysis (using the thiocyanate anion as the Lewis base) and hence is
Graphical Abstract
Scheme 1: Synthesis and transformation of nonracemic silyl-protected cyanohydrins.
Figure 1: Highly active metal(salen) complexes for asymmetric cyanohydrin synthesis.
Scheme 2: Synthesis of cyclic carbonates.
Scheme 3: Synthesis of cyanohydrin trimethylsilyl ethers and acetates.
Scheme 4: Equilibrium between bimetallic and monometallic Ti(salen) complexes.
Figure 2: Second-order kinetics plot for the addition of TMSCN to benzaldehyde at 0 °C catalysed by complex 2...
Figure 3: Plot of k2obs against [2], showing that the reactions are first order with respect to the concentratio...
Figure 4: Eyring plot to determine the activation parameters for catalyst 2 in propylene carbonate. The red a...
Figure 5: 51V NMR spectra of complex 2 recorded at 50 °C. a) Spectrum in CDCl3; b) spectrum in CDCl3 with 500...
Figure 6: Structures consistent with the 51V NMR spectra.
Figure 7: Bimetallic aluminium(salen) complex for asymmetric cyanohydrin synthesis.
Figure 8: Rate determining transition states for asymmetric cyanohydrin synthesis: a) when Lewis base catalys...
Figure 9: Hammett correlations with catalyst 2 at 0 °C. Data in red are obtained in dichloromethane [52], whilst ...
Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation
- Vladimir N. Boiko
Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88
Graphical Abstract
Figure 1: Examples of industrial fluorine-containing bio-active molecules.
Figure 2: CF3(S)- and CF3(O)-containing pharmacologically active compounds.
Figure 3: Hypotensive candidates with SRF and SO2RF groups – analogues of Losartan and Nifedipin.
Figure 4: The variety of the pharmacological activity of RFS-substituted compounds.
Figure 5: Recent examples of compounds containing RFS(O)n-groups [12-18].
Scheme 1: Fluorination of ArSCCl3 to corresponding ArSCF3 derivatives. For references see: a[38-43]; b[41,42]; c[43]; d[44]; e[38-43,45-47]; f[38-43,48,49]; g...
Scheme 2: Preparation of aryl pentafluoroethyl sulfides.
Scheme 3: Mild fluorination of the aryl SCF2Br derivatives.
Scheme 4: HF fluorinations of aryl α,α,β-trichloroisobutyl sulfide at various conditions.
Scheme 5: Monofluorination of α,α-dichloromethylene group.
Scheme 6: Electrophilic substitution of phenols with CF3SCl [69].
Scheme 7: Introduction of SCF3 groups into activated phenols [71-74].
Scheme 8: Preparation of tetrakis(SCF3)-4-methoxyphenol [72].
Scheme 9: The interactions of resorcinol and phloroglucinol derivatives with RFSCl.
Scheme 10: Reactions of anilines with CF3SCl.
Scheme 11: Trifluoromethylsulfanylation of anilines with electron-donating groups in the meta position [74].
Scheme 12: Reaction of benzene with CF3SCl/CF3SO3H [77].
Scheme 13: Reactions of trifluoromethyl sulfenyl chloride with aryl magnesium and -mercury substrates.
Scheme 14: Reactions of pyrroles with CF3SCl.
Scheme 15: Trifluoromethylsulfanylation of indole and indolizines.
Scheme 16: Reactions of N-methylpyrrole with CF3SCl [80,82].
Scheme 17: Reactions of furan, thiophene and selenophene with CF3SCl.
Scheme 18: Trifluoromethylsulfanylation of imidazole and thiazole derivatives [83].
Scheme 19: Trifluoromethylsulfanylation of pyridine requires initial hydride reduction.
Scheme 20: Introduction of additional RFS-groups into heterocyclic compounds in the presence of CF3SO3H.
Scheme 21: Introduction of additional RFS-groups into pyrroles [82,87].
Scheme 22: By-products in reactions of pyrroles with CF3SCl [82].
Scheme 23: Reaction of aromatic iodides with CuSCF3 [93,95].
Scheme 24: Reaction of aromatic iodides with RFZCu (Z = S, Se), RF = CF3, C6F5 [93,95,96].
Scheme 25: Side reactions during trifluoromethylsulfanylation of aromatic iodides with CF3SCu [98].
Scheme 26: Reactions with in situ generated CuSCF3.
Scheme 27: Perfluoroalkylthiolation of aryl iodides with bulky RFSCu [105].
Scheme 28: In situ formation and reaction of RFZCu with aryl iodides.
Figure 6: Examples of compounds obtained using in situ generated RFZCu methodology [94].
Scheme 29: Introduction of SCF3 group into aromatics via difluorocarbene.
Scheme 30: Tetrakis(dimethylamino)ethylene dication trifluoromethyl thiolate as a stable reagent for substitut...
Scheme 31: The use of CF2=S/CsF or (CF3S)2C=S/CsF for the introduction of CF3S groups into fluorinated heteroc...
Scheme 32: One-pot synthesis of ArSCF3 from ArX, CCl2=S and KF.
Scheme 33: Reaction of aromatics with CF3S− Kat+ [115].
Scheme 34: Reactions of activated aromatic chlorides with AgSCF3/KI.
Scheme 35: Comparative CuSCF3/KI and Hg(SCF3)2/KI reactions.
Scheme 36: Me3SnTeCF3 – a reagent for the introduction of the TeCF3 group.
Scheme 37: Sandmeyer reactions with CuSCF3.
Scheme 38: Reactions of perfluoroalkyl iodides with alkali and organolithium reagents.
Scheme 39: Perfluoroalkylation with preliminary breaking of the disulfide bond.
Scheme 40: Preparation of RFS-substituted anilines from dinitrodiphenyl disulfides.
Scheme 41: Photochemical trifluoromethylation of 2,4,6-trimercaptochlorobenzene [163].
Scheme 42: Putative process for the formation of B, C and D.
Scheme 43: Trifluoromethylation of 2-mercapto-4-hydroxy-6-trifluoromethylyrimidine [145].
Scheme 44: Deactivation of 2-mercapto-4-hydroxypyrimidines S-centered radicals.
Scheme 45: Perfluoroalkylation of thiolates with CF3Br under UV irradiation.
Scheme 46: Catalytic effect of methylviologen for RF• generation.
Scheme 47: SO2−• catalyzed trifluoromethylation.
Scheme 48: Electrochemical reduction of CF3Br in the presence of SO2 [199,200].
Scheme 49: Participation of SO2 in the oxidation of ArSCF3−•.
Scheme 50: Electron transfer cascade involving SO2 and MV.
Scheme 51: Four stages of the SRN1 mechanism for thiol perfluoroalkylation.
Scheme 52: A double role of MV in the catalysis of RFI reactions with aryl thiols.
Scheme 53: Photochemical reaction of pentafluoroiodobenzene with trifluoromethyl disulfide.
Scheme 54: N- Trifluoromethyl-N-nitrosobenzene sulfonamide – a source of CF3• radicals [212,213].
Scheme 55: Radical trifluoromethylation of organic disulfides with ArSO2N=NCF3.
Scheme 56: Barton’s S-perfluoroalkylation reactions [216].
Scheme 57: Decarboxylation of thiohydroxamic esters in the presence of C6F13I.
Scheme 58: Reactions of thioesters of trifluoroacetic and trifluoromethanesulfonic acids in the presence of ar...
Scheme 59: Perfluoroalkylation of polychloropyridine thiols with xenon perfluorocarboxylates or XeF2 [222,223].
Scheme 60: Interaction of Xe(OCORF)2 with nitroaryl disulfide [227].
Scheme 61: Bi(CF3)3/Cu(OCOCH3)2 trifluoromethylation of thiophenolate [230].
Scheme 62: Reaction of fluorinated carbanions with aryl sulfenyl chlorides.
Scheme 63: Reaction of methyl perfluoromethacrylate with PhSCl in the presence of fluoride.
Scheme 64: Reactions of ArSCN with potassium and magnesium perfluorocarbanions [237].
Scheme 65: Reactions of RFI with TDAE and organic disulfides [239,240].
Scheme 66: Decarboxylation of perfluorocarboxylates in the presence of disulfides [245].
Scheme 67: Organization of a stable form of “CF3−” anion in the DMF.
Scheme 68: Silylated amines in the presence of fluoride can deprotonate fluoroform for reaction with disulfide...
Figure 7: Other examples of aminomethanols [264].
Scheme 69: Trifluoromethylation of diphenyl disulfide with PhSO2CF3/t-BuOK.
Scheme 70: Amides of trifluoromethane sulfinic acid are sources of CF3− anion.
Scheme 71: Trifluoromethylation of various thiols using “hyper-valent” iodine (III) reagent [279].
Scheme 72: Trifluoromethylation of p-nitrothiophenolate with diaryl CF3 sulfonium salts [280].
Scheme 73: Trifluoromethyl transfer from dibenzo (CF3)S-, (CF3)Se- and (CF3)Te-phenium salts to thiolates [283].
Scheme 74: Multi-stage paths for synthesis of dibenzo-CF3-thiophenium salts [61].
