Kunihiko Akutagawa

Carbon dioxide : a reagent for the simultaneous protection of nucleophilic centers and the activation of alternative locations to electrophilic attack. XVI, A novel synthetic method for the side-chain functionalization of N-methyl-o-toluidine and for the preparation of 2-substituted N-methylindoles

N-Methyl-o-toluidine is readily converted into a range of side-chain functionalized derivatives in a one-pot sequence, using carbon dioxide for N-protection. The intermediate lithium carbamate is further lithiated by butyllithium at the side-chain methyl group, and then reacted with an electrophile; the product undergoes acid-catalyzed decarboxylation during work-up. 2-Substituted N-methylindoles are produced when carboxylate esters are used as electrophiles. The yields are good, and no ring-substituted products are detected

A convenient preparation of N- (arenesulfonyl) sulfoximines by oxidation of N- (arenesulfonyl) sulfilimines with sodium hypochlorite in a two phase system

Abstract N-(Arenesulfonyl) sulfilimines can be oxidized to the corresponding sulfoximes in high yields with sodium hypochlorite in an AcOEt-H 2 O two phase system in the presence of quaternary ammonium salts as catalysts.

CONVENIENT PREPARATION AND SPECTROSCOPIC STUDIES OF SULFOXIMINES AND SULFONEDIIMINES: N-CHLOROSULFILIMINE AS KEY INTERMEDIATE

Abstract N-Unsubstituted sulfilimines, when reacted with sodium hypochlorite in an aqueous alkaline methanol solution or with Chloramine-T in dry acetonitrile in the presence of excess sodium salt of tosylamide were converted to the corresponding N-unsubstituted sulfoximines (1) or mono-N-tosylsulfonediimines (2) in good yields. 2 gave the unsubstituted sulfonediimines (3) in high yields upon treatment with conc. H2SO4. N-Chlorosulfilimine (5) was isolated in the initial stage of these reactions. 5 was found to react with NaOH in aqueous methanol and also with anhydrous Chloramine-T in dry acetonitrile to yield the corresponding 1 and 2 in good yields. IR, NMR, and Mass spectroscopic studies of 1, 2, and 3 were also carried out.

THERMOLYSES AND REACTIONS WITH NUCLEOPHILES OF N-SULFUR-GROUP-SUBSTITUTED SULFOXIMINES

Abstract Thermolyses and reactions with nucleophiles of S,S-diphenylsulfoximines (1) bearing the following N-sulfur-substituents, i.e., N-p-tolylthio-(b), N-p-tolylsulfinyl-(c), N-(N′-p-tolylsulfonyl-p-toluenesulfinimidoyl)-(d), N-(S′,S′-diphenylsulfonio)-(e), N-p-tolylsulfonyl-(f), and N-(N′-p-tolylsulfonyl-p-toluenesul-fonimidoyl)-(g), have been examined. The former three sulfoximines (1b-d) are thermally unstable and readily decompose to form diphenyl sulfoxide and diphenyl sulfide by the initial cleavage of the S[sbnd]N linkage in the original sulfoximines. The latter three sulfoximines (1e-g) fairly stable thermally. 1b-d were found to react with several nucleophiles to afford the corresponding sulfenylated, sulfinylated or sulfinimidoylated products together with N-unsubstituted sulfoximine (1a). 1e was found to react with potassium hydroxide/methanol or chloramine-T/N,N-dimethylformamide to afford diphenyl sulfoxide or S,S-diphenyl-(N-p-tolylsulfonyl)sulfilimine along with 1a in good yields. The la...

Internal 1,2-Aryl Migration in the Thermolyses of N-Unsubstituted S-p-and S-o-Nitrophenylsulfilimines

Abstract o- or p-Nitroaniline was obtained when thermolysis of N-unsubstituted S-o-nitrophenyl- or p-nitrophenyl-S-phenylsulfilimine was carried out at 50–100°C without solvent.

COPPER CATALYZED REACTIONS OF S,S-DIARYL-N-TOSYLSULFILIMINES WITH SULFOXIDES: NEW SYNTHESIS OF N-TOSYLSULFOXIMINES

Abstract S,S-Diaryl-N-tosylsulfilimines were readily reduced by treatment with copper to give the corresponding sulfides and a copper-tosylnitrenoid-complex which upon reacting with sulfoxides afforded the corresponding N-tosylsulfoximines, derived from sulfoxides in fair yields. When optically active (-)-(S)-methyl phenyl sulfoxide was used, the corresponding (+)-N-tosylsulfoximine was obtained together with the sulfide derived from the N-tosylsulfilimine. The stereochemical course of the conversion of (-)-(S)-sulfoxide to (+)-N-tosylsulfoximine was found to be mainly retention (76%) with partial racemization due to thermal pyramidal inversion of the starting sulfoxide.