Giuseppe Cremonesi

Heterocycles from ylides. Part IX. A convenient synthesis of 1-sulfonyl-2,3-disubstituted 2,3-dihydroindoles

The reaction of sulfur ylides (1) with N-(2-bromomethylphenyl)benzenesulfonamides (4) gives 2,3-dihydroindoles (5) whose structure and stereochemistry were assigned on the basis of analytical and spectroscopic data. Some chemical transformations of 5 are reported.

Heterocycles from Ylides. Part X. Synthesis of 3-Hydroxy-2,3-dihydroindoles by a Domino Reaction

A domino reaction between 2-N-phenylsulfonylaminobenzaldehyde (1) and sulfonium ylides (2) leads to 3-hydroxy-2,3-dihydroindoles (3) whose structure was confirmed on the basis of analytical and spectroscopic data.

Combinatorial Chemical Synthesis of 4-Heteroaryl-3-substituted Pyrroles from Nitroalkenes

A small library of 4-(2-furyl)- or 4-(2-thienyl)-3-substituted pyrroles has been prepared by reaction of 2-(2-furyl or 2-thienyl)-1-nitro-1-alkenes (1) with secondary enamines (2). The reaction gives pyrrole derivatives by means of a Michael-type addition intermediate. Cyclization is influenced by the nature of the solvent and the substituent in the enamine β position, and by enamine-nitrogen nucleophilicity.

QUINOLINE DERIVATIVES BY CYCLOCONDENSATION OF N-(2-BROMOPHENYLMETHYLPHENYL)BENZENESULFONAMIDE WITH ENOL ETHERS AND ENAMINES

The reaction of N-(2-bromophenylmethylphenyl)benzenesulfonamide (1) with electron rich alkenes (enol ethers (2), (3) and enamines (4)) gives quinoline derivatives 5 and ring fused quinoline 6, 7 whose structures were assigned on the basis of analytical and spectroscopic data. The chemical behavior of adducts 5 and 7 is reported.

Synthesis of 2-Hydroxy-1,2,3,4-tetrahydroquinoline Derivatives by a Cyclocondensation Reaction

The reaction of enolates (2) of 1,3-dicarbonyl compounds with N-(2-bromomethylphenyl)benzenesulfonamides (1) gives N-phenylsulfonyl-2-hydroxy-1,2,3,4-tetrahydroquinoline derivatives (3) whose structure and stereochemistry were assigned on the basis of analytical and spectroscopic data. Some studies on the chemical behaviour of 3 are also reported.

Tetrahydroquinazoline derivatives by aza Diels-Alder reaction

The reaction of N-(2-Chloromethylphenyl)benzenesulfonamides (1) with N-benzylideneamines (2) gives 1,2,3,4-tetrahydroquinazoline derivatives (3) via the highly reactive o-azaxylylene intermediates. The structure of (3) is fully assigned on the basis of analytical and spectroscopic data. The chemical behaviour of (3) has been studied.

Heterocycles from ylides. Part XI. Synthesis of 2-substituted quinoline derivatives

The reaction of 2-N-phenylsulfonylaminobenzaldehyde (1) with stabilized alkylidene phosphoranes (2) gives, through a Wittig condensation followed by reduction of intermediate alkenes and cyclization with PPA, quinoline derivatives (5).