Regioselective Synthesis of Benzofuran‐Annulated Six‐Membered Sulfur Heterocycles by Aryl Radical Cyclization

The tin hydride–mediated cyclization of a number of sulfides and sulfones under mild and neutral conditions has been investigated. The sulfides were in turn derived from 3(2H) benzothiofuranone and 2‐bromobenzyl bromides by phase‐transfer‐catalyzed reaction, and the corresponding sulfones were prepared by treatment of the corresponding sulfides with m‐CPBA at room temperature. The sulfides and sulfones were then reacted with ⁿ Bu₃SnH‐AIBN to afford regioselectively benzofuran‐annulated six‐membered sulfur heterocycles.     

Regioselective Synthesis of 1,8-Naphthyridinone-Annulated Oxygen and Sulfur Heterocycles by Tri-n-butyl Tinhydride–Mediated Aryl Radical Cyclization

The tin hydride–mediated cyclizations of a number of ethers, sulfides, and sulfones under mild, neutral conditions have been investigated. While the 2-bromobenzyloxy ethers were prepared in 62–65% yields by the alkylation of 4-hydroxy-1-phenyl-1,8-naphthyridin-2(1H)-one with 2-bromobenzyl bromides in refluxing acetone in the presence of anhydrous potassium carbonate, the sulfides were derived from 4-mercapto-1-phenyl-1,8-naphthyridin-2(1H)-one and 2-bromobenzyl bromides in 82–84% yields by a phase-transfer catalysis (PTC) reaction. The corresponding sulfones were prepared by treatment of the sulfides with m-CPBA in refluxing dichloromethane. The ethers, sulfides, and the sulfones were treated with ⁿ Bu₃SnH-AIBN to give regioselectively 1,8-naphthyridinone-annulated oxygen and sulfur heterocycles in 70–78% yields.     

Products of Reaction of Tricyclo[4.1.0.02,7]heptane and 1-Bromotricyclo[4.1.0.02,7]heptane with Hydrogen Sulfide,and Syntheses Based Thereon

By reactions of 1-R-tricyclo[4.1.0.02,7]heptanes (R = H, Br) with hydrogen sulfide initiated by UV irradiation endo-6-bicyclo[3.1.1]heptanethiols and bis(endo-6-bicyclo[3.1.1]heptyl) sulfides were synthesized. The sulfides were oxidized to the corresponding sulfoxides and sulfones. The results of HBr elimination from the bromine-substituted sulfoxides and sulfones effected by potassium tert-butylate are discussed. The latter reaction results in the recovery of the system of 1-substituted tricyclo[4.1.0.02,7]heptane.     

Regioselective synthesis of quinolone-annulated sulfur heterocycles by aryl radical cyclization

The tin hydride-mediated cyclizations of a number of sulfides and sulfones under mild, neutral conditions, have been investigated accompanied by some amount of β-scission product for sulfides. The sulfides were derived from 4-mercaptoquinolone and 2-bromobenzyl bromides by phase transfer catalyzed reaction and the corresponding sulfones were prepared by treatment of the sulfides with m-CPBA at room temperature. The sulfides and the corresponding sulfones were then reacted with ⁿBu₃SnH-AIBN to give regioselective quinolone-annulated sulfur heterocycles.     

Neue Synthesemethoden, 4. Mitt.: Milde einphasenoxidation von Sulfiden und Sulfoxiden zu Sulfonen

The mild oxidation of sulfides and sulfoxides to sulfones with benzyltriethylammoniumpermanganate in organic solvents is described.

1Scholz, D., in Vorbereitung.     

Syntheses de nouveaux heterocycles pyrroliques: Des thiepino[4,5-c]- et [4,5-b]pyrroles

The reaction of N-methylpryrrole-3,4-dicarboxaldehyde ) I )and N-methylpyrrole-2,3-dicarboxaldehyde ) 2 ) with sulfones affored thiepimo[4,5-c]-pyrrole 6,6-dioxides and the thiepimo[4,5-b]pyrrole 6,6-dioxides, respectively. Attempts to condense sulfides with 1 yielded the thiepino[4,5-c]-pyrrole ring system, however sulfides with 2 resulted in benzo-annelation.     

Notizen zur Synthese von 2-Aminophenylsulfonen

Syntheses of some Alkyl, Cycloalkyl and Aryl 2-Aminophenyl Sulfones Syntheses of the alkyl, cycloalkyl and aryl 2-aminophenyl sulfones 10 were achieved by oxidation of the corresponding 2-nitrophenyl sulfides 7 to the 2-nitrophenyl sulfones 9 followed by ethanolic Béchamp-reduction. The sulfides 7 in turn were obtained either by reactions of 2-nitro-thiophenol ( 8 ) with the appropriate alkyl and cycloalkyl halides or of 2-chloro-nitrobenzene ( 5 ) with the relevant thiols. Condensation of 2-nitrobenzenesulfinic acid ( 3 ) with bromoacetic acid in aqueous alkaline solution led - presumably via 2-nitrophenylsulfonylacetic acid ( 4 ) - to methyl 2 nitrophenyl sulfone ( 1 ), reduction of which gave 2-aminophenyl methyl sulfone ( 2 ). Treatment of 2-aminothiophenol ( 11 ) with t-butyl alcohol in aqueous sulfuric acid gave 2-aminophenyl t-butyl sulfide ( 12 ), which was acetylated to o-t-butylthio-acetanilide ( 13 ). Oxidation of the latter to o-t-butylsulfonyl-acetanilide ( 14 ) followed by hydrolysis led to 2-aminophenyl t-butyl sulfone ( 15 ).     

Synthesis,phosphodiesterase inhibition and antiinflammatory activity of 2-aryl-3-hydroxythieno[2,3-b]quinoline 1,1-dioxides. Application of sodium chlorite as a novel reagent for the (Stepwise) oxidation of sulfides to sulfones

Synthesis of five 2-aryl-3-hydroxythieno[2,3-b]quinoline 1,1-dioxides (38-42) from 3-formylquinoline-2-thiol ( 3 ) via a facile oxidation-cyclization sequence is reported. Reaction of appropriate benzyl chlorides with the thiol ( 3 ) in the presence of sodium methoxide gave excellent yields of the corresponding benzyl 2-(3-formylquinolyl) sulfides (4-8) . Direct oxidation of these sulfides to the corresponding sulfones (23-27) was effected with excess sodium chlorite in aqueous pyridine. Esterification of these sulfone-acids followed by brief treatment of the resulting esters 28-32 with sodium methoxide gave the desired compounds 38-42 after acidification. The benzyl 2-(3-formylquinolyl) sulfides were also selectively oxidized to the corresponding sulfoxides (13-17) . Thus sodium chlorite has proved to be an effective reagent for the stepwise oxidation of sulfides to sulfones. The title compounds were potent inhibitors of cyclic AMP phosphodiesterase, but failed to display significant antiinflammatory effects in the carrageenan rat paw edema test or significant activity in the phenylquinone induced writhing test for analgesia.     

Radical-mediated thiodesulfonylation of the vinyl sulfones: access to (α-fluoro)vinyl sulfides

Radical-mediated thiodesulfonylation of the vinyl and (α-fluoro)vinyl sulfones, derived from aldehydes and ketones, with aryl thiols in organic or aqueous medium provided access to vinyl and (α-fluoro)vinyl sulfides. The vinyl sulfides were formed predominantly with E stereochemistry independent of the stereochemistry of the starting vinyl sulfones.     

Ru-Catalyzed Oxidations with Iodosylbenzene Derivatives. Substituent Effects on Selectivity in Oxidation of Sulfides and Alcohols

Oxidation of sulfides with PhIO/RuCl₂ (PPh₃)₃ leads to sulfones. Electronwithdrawing substituents in the aromatic ring of PhIO reduce the reactivity and improves selectivity of the system. Thus, with m-iodosylbenzoic acid sulfides are converted to sulfoxide. Under the same conditions aliphatic primary alcohols are transformed to aldehydes with m-iodosylbenzoic acid, while PhIO affords carboxylic acids.     

Studies on Reactivity of Bisolefinic Diketo Sulfides/Sulfones. II

Abstract

The cycloaddition of diazomethane to bis(1-aryl-2-propen-1-one) sulfides/sulfones (1/2) and cyclocondensation of 1/2 with hydrazine hydrate has been studied.     

Metal-free chemoselective oxidation of sulfides by in situ generated Koser’s reagent in aqueous media

Selective oxidation of sulfides was successfully performed by employing phenyliodine diacetate as an oxidant with the catalysis of TsOH in aqueous solution under mild conditions. Sulfoxides were formed with 1.1 equiv of PhI(OAc)₂ at room temperature; whereas sulfones were obtained in the presence of 2.1 equiv of PhI(OAc)₂ at 80 °C under otherwise identical conditions. Notably, various sulfides were converted to corresponding sulfoxides or sulfones in good to high yields by this metal-free protocol.     

Oxidation of organic sulfides and disulfides with a tert-butyl hydroperoxide-aluminum tri-tert-butoxide system

Methyl phenylethynyl and phenyl phenylethynyl sulfides are selectively converted into methyl phenylethynyl and phenyl phenylethynyl sulfones, respectively, under the action of system tert-butyl hydroperoxide-aluminum tri-tert-butoxide in benzene at 20 °C. The analogous oxidation of diphenyl disulfide results in S-phenyl benzenethiosulfonate.     

Synthesis and Antimicrobial Evaluation of Novel N-Substituted β-Hydroxy Benzimidazole Sulfone Fluoroquinolones by Selective Oxidation Using Ticl4-H2O2

Abstract

The synthesis of N-substituted β-hydroxy benzimidazole sulfones containing 8-methoxy fluoroquinolone has been described and they were evaluated for antimicrobial activities. The compounds of N-substituted β-hydroxy benzimidazole sulfides (4a–e) and N-substituted β-hydroxy benzimidazole sulfones (5a–e) at C-7 of fluoroquinoline exhibited superior activity in vitro. 8-Methoxy fluoroquinolone carboxylic acid (1), reaction with piperizine in acetonitrile in presence of triethylamine under reflux gives 7-piperazinyl-8-methoxyfluoroquinolone (2). The latter is reacted with epichlorohydrine in presence of NaOH in acetone yielded N-substituted epoxide (3), which on treatment with 5-substituted-2-mercaptobenzimidazoles gives N-substituted β-hydroxy benzimidazole sulfides (4). Further, 4 on treatment with TiCl₄-H₂O₂ and in DCM yielded the corresponding N-substituted β-hydroxy benzimidazole sulfone (5).     

Chiral sulfoxides from (R)-α- dimethylaminoethylferrocene

Chiral sulfoxides and sulfones of potential interest in organic synthesis are prepared by the reaction of 2-lithio-1-(dimethylaminoethyl)-ferrocene with disulfides, followed by oxidation of the sulfides thus obtained with sodium metaperiodate on alumina or with 3-chloropcrbenzoic acid. Most of the reactions, in particular oxidations of the sulfides to form the sulfoxides, proceed with high diastereoselectivity. The sulfoxides and sulfones can be isolated as pure enantiomers. Assignment of absolute configurations is based on independent synthesis together with ¹H- and ¹³C-NMR data and ORD measurements.     

Selective Oxidation of Sulfides to Sulfones Using H2O2 and Anderson-Type Hexamolybdochromate(III) as Catalyst

An Anderson-type hexamolybdochromate(III) is found to be an effective catalyst for the selective oxidation of sulfides to their corresponding sulfones. The reaction was carried out in 60% aq. acetonitrile (v/v) using 30% H₂O₂ at 60°C. Various dialkyl, alkyl-aryl, and diaryl sulfides were selectively oxidized, giving high yields of sulfones after a simple workup procedure.     

SYNTHESIS AND BIOLOGICAL ACTIVITIES OF NEW INDOLE DERIVATIVES CONTAINING SULFIDE AND/OR SULFONE MOIETIES. PART I

Abstract

4-Amino-halonitrodiphenyl sulfides(I) and/or 4-amino-halonitrodiphenyl sulfones have been found to react with isatin, N-acetyl isatin, isatin-N-Mannich bases, indole-3-carboxaldehyde and N-substituted indole-3-carboxaldehyde producing the corresponding indole derivatives. The biological activity of some of these products was screened against selected strains of bacteria.     

Some Comments on the Conformations of Methyl Phenyl Sulfides,Sulfoxides and Sulfones

¹³C-NMR. and He (Iα) photoelectron spectra of alkyl phenyl sulfides, sulfoxides and sulfones have been used to probe how their conformations depend on the size of the alkyl groups R. The results are interpreted to indicate that in the sulfides the S, R-bond is twisted out of the planar conformation with increasing size of the alkyl group, whereas in the sulfoxides and sulfones the preferred conformation with the S, R-bond perpendicular to the phenyl group plane seems to be independent of the size of R. These conclusions are in agreement with previous work on the alkyl phenyl sulfides and provide strong support for previous conjectures concerning the preferred conformations of alkyl phenyl sulfoxides and sulfones.     

Stereoselective Synthesis of Substituted 2-(Z-Styrylsulfonyl)-1H-imidazoles and Benzothiazole

A novel method has been reported involving the synthesis of z-styryl sulfides by the reaction of phenylacetylene with 2-mercpto benzimidazoles and benzthiazole using NaOH as a base in absolute ethanol. On further oxidation with H₂O₂, these resulted in the formation of the desired styryl sulfones in good yields with retention of stereochemistry.     

Asymmetric Claisen Rearrangements on Chiral Vinyl Sulfoxides

Highly diastereoselective Claisen rearrangements of acyclic allyl vinyl ethers bearing a chiral sulfoxide at C‐5 provide γ‐δ‐unsaturated aldehydes or ketones with up to two consecutive asymmetric centers in the molecule whilst preserving a useful vinyl sulfoxide. The reactivity of related vinyl sulfides and sulfones has also been examined in this work.