Georges Morel

Action des phenylacetonitriles α-substitues sur les tetrahalomethanes en milieu basique: Mecanismes de l'halogenation et de la duplication

Abstract Carbanions of substituted phenylacetonitriles are halogenated by carbon tetrachloride or carbon tetrabromide, and also converted into symmetrically-substituted succinonitriles. The halogenation occurs via an ionic process, and the formation of succinonitriles via a radical process, essentially a no-chain mechanism in the case of diphenylacetonitrile anion, confirmed by the course of the reaction of p-nitrobenzylchloride on the diphenylacetonitrile anion.

Synthesis of thioimidates by insertion of TerT-butylisocyanide into the C-S bond of activated sulfides. Rearrangement of thioimidates by 1,3 C to N migration of an alkoxycarbonyl group

Abstract Tert-butylisocyanide inserts into the carbon-sulfur bond of α-cyano sulfides 2 - 6 to give thioimidates 10 - 14 . The thioimidates can also be obtained via the chlorine substitution of the tert-butylimino chloro sulfides 27 - 28 , which is a more general method. These thioimidates rearrange to E and Z isomers of N-vinylcarbamates 16 - 20 via a 1,3 C to N migration of the alkoxycarbonyl group.

Addition nucleophile des anions d'esters α-cyanoacetiques sur les cations succinimidosulfonium: Fragmentation ionique ou radicalaire des′ σ-sulfuranes intermediaires

Abstract Reactions of substituted cyanoacetate anions 4 with S,S-dialayklsuccinimidosulfonium salts resulted generally in the formation of N-alkylthiomethylketenimines and α-alkylthiomethylesters. Coupling products were also obtained with anion 4d and only observed in the case of methyl phenylcyanoacetate anion 4b. The results were interpreted by the formation of instable σ-sulfurane intermediates. Homolytic cleavage of these intermediates gave radical pairs, then the coupling products. Heterocyclic clevage gave new sulfonium salts which rearranged via sulfonium ylides.

Addition of isocyanides to ?-(methylthio)-benzylidenamidinium iodides: A surprising access to 2-(dialkylamino)imidazoles and 3,5-diamino-2H-pyrrolium salts

A number of 2-(dialkylamino)-5-(methylthio)imidazoles 2 are obtained by treating the formamidinium iodides 1a,b with isocyanides R3 NC under mild conditions. Reduction of these species can occur in the reaction medium to furnish the corresponding imidazoles 3. In some cases, double cycloaddition across the imine bond of starting salts 1 also provides the (azetidin-1-yl-methylene)ammonium iodides 4. Reactions with tert-butyl and isopropyl isocyanides in refluxing acetonitrile convert the acetamidinium iodide 1c into the 3,5-diamino-2H-pyrrolium salts 7. Mechanisms are suggested to account for these ring-closure processes.

A MILD AND EFFICIENT TRIPHOSGENE-MEDIATED CYCLODEHYDRATION OF 2-(IMIDOYLTHIO)CARBOXAMIDES. SYNTHESIS AND CHEMISTRY OF 4-AMINO-2-(METHYLTHIO)THIAZOLIUM CHLORIDES

Abstract 4-Aminothiazolium salts 1 are conveniently prepared in a one-step procedure from 2-(imi-doylthio)carboxamides 4 and triphosgene in the presence of pyridine. Their chemical reactions are discussed, including addition to dimethyl acetylenedicarboxylate and carbon disulfide in a basic heterogeneous medium.

Evidence for the participation of a nitrile group in [2,3] sigmatropic rearrangements of sulphonium ylides

The formation of N-methylthiomethylketenimines from the reaction of α-cyanoalkyl-dimethylsulphonium salts with n-butyl-lithium or triethylamine occurs by way of a [2,3] sigmatropic rearrangement of intermediate ylides.