I. I. Popov

Synthesis of ?-(4,5-dihalofuryl)acrylic and -propiolic acids

Reaction of 4,5-dihalofurfurals with acetaldehyde and with carbethoxybromomethylenephosphorane gave, respectively, 4,5-dihalofurylacroleins and β-(4,5-dihalo-2-furyl)-α-bromoacrylic acid esters. The latter were converted to 4,5-dihalo-2-furylpropiolic acids by the action of alkali.

Transformations of 2-formyl-n-nitroarylimidazoles

Esters of-1-aryl-β-2-imidazolylacrylic acid were synthesized by the Wittig reaction from 2-formyl-1-arylimidazoles. The reaction of these aldehydes with arylamines and 1,2-dianilinoethane was examined.

INVESTIGATIONS OF UNSATURATED AZOLES. 13. SYNTHESIS AND SOME REACTIONS OF 1-ALKYLBENZIMIDAZOLES

Methods of direct alkylation of benzimidazoles by haloatkanes in homogeneous medium and under phase transfer catalysis conditions together with cyanoethylation by acrylonitrile are reported. The dealkylation of quaternary benzimidazole salts was also studied.

Research on benzimidazole derivatives

The acylation of 2-amino derivatives of benzimidazole and pyridine withβ-aryl-α, β-unsaturated carboxylic acid chlorides gave the corresponding amides, which were converted to 2-oxo derivatives of pyrimido [1,2-a]benzimidazole and pyridine by the action of bases.

Research of benzimidazole derivatives. XXXVI. Synthesis and transformations of N-propargyl-substituted 2-aminobenzimidazoles

Abstract1-(2′-Propynyl)-2-aminobenzimidazole and 1,3-di(2′-propynyl)-2-iminobenzimidazoline, which are cyclized by the action of bases to imidazo[1,2-a]benzimidazole derivatives, were obtained by alkylation of 2-aminobenzimidazole with propargyl bromide. The cyclization proceeds with the formation of intermediate N-propadienyl derivatives.

Conversions of 2-α-chloroalkylbenzimidazoles

Upon interaction with caustic in a DMSO medium, 2-chloromethylbenzimidazoles are subjected to cyclodimerization, forming 5H,12H-pyrazino[1,2-a:4,5-a′]bis-benzimidazoles; in the presence of nucleophiles (ammonia, amines, anions of β-diketones), under the indicated conditions, the products are the corresponding substituted amines or derivatives of pyrrolo[1,2a]benzimidazole.

Condensed derivatives of benzazoles. 1. Synthesis of 6- and 5-substituted benzimidazo[2,1-b]quinazolin-12-ones

Abstract6(5)H-Benzimidazo[2,1-b]quinazolin-12-one was obtained in high yield by condensation of benzimidazole-2-sulfonic acid with anthranilic acid. Methods for the introduction of substituents selectively into the 5 and 6 positions of this heterocycle were developed.

Research on unsaturated azole derivatives

The reaction of benzimidazole with phenylacetylene, ethyl propiolate, and their β-bromo derivatives leads to the corresponding β-substituted N-vinylbenzimidazoles.

Research on unsaturated azole derivatives: V. Transformations of 3-formylindazoles in the wittig reaction

Abstract3-Formylindazoles are converted to 1-methyl- and 2-methyl-substitutedβ-(3-indazolyl)acrylic andα-bromoacrylic acids by the Wittig reaction. Dehydrohalogenation of theβ-(3-indazolyl)-α-bromoacrylic acid esters gaveβ-(3-indazolyl)propiolic acids, the decarboxylation of which gives isomeric 1-methyl- and 2-methyl-substituted 3-ethynylindazoles.

Research on benzimidazole derivatives XXXIV. Some transformations of N-alkenyl- and N-alkynyl-substituted benzimidazoles

Benzimidazole was alkylated with 1,3-dibromo-1-propene, 2,3-dibromo-1-propene, and 1,2,3-tribromopropane, and some of the properties of the N-substituted benzimidazoles obtained were examined. It is shown that 1-(2′-propynyl)benzimidazole is readily rearranged to the 1-propadienyl derivative under the conditions of the Favorskii reaction.