L. Ya. Oleinikova

Research on the chemistry of 2-hetarylbenzimidazoles. 5. Acylation of 1-methyl-2-(2′-hetaryl)benzimidazoles

The acylation of 1-methyl-2-(2′-furyl)- and 1-methyl-2-(2′-thienyl)benzimidazoles was studied. A convenient method for the formylation of the furan and thiophene rings by the action of urotropin in polyphosphoric acid (PPA) was found. Acylation of the furan and thiophene rings was realized by the action of acetic acid and aromatic carboxylic acids in PPA.

Research on the chemistry of 2-hetarylbenzimidazoles

The condensation of 1-methyl-2-formylpyrrole with o-phenylenediamine gave 2-(1′-methyl-2′-pyrrolyl)benzimidazole, which was subjected to methylation. The alkylation product was subjected to electrophilic substitution. The substituent is incorporated in the 4 or 5 position of the hetaryl ring; however, bromination of 1-methyl-2-(1′-methyl-2′-pyrrolyl)benzimidazole leads to the formation of the mono-, di-, and tribromo derivatives, depending on the conditions. The acidophobic properties of the pyrrole ring are partially lost as a consequence of the effect of the benzimidazole ring.

Synthesis and transformations of 2-(2-furyl)-and 2-[?;-(2-furyl)vinyl]naphth[1,2-d]imidazoles

The corresponding 2-(2-furyl)naphth[1,2-d]imidazoles were obtained by heating Schiff bases, prepared from 1,2-naphthalenediamine and furfural and 5-bromo- and 5-nitrofurfurals, in nitrobenzene. 2-[β-(2-Furyl)vinyl]naphth[1,2-d]imidazoles were synthesized by condensation of 2-methylnaphth[1,2-d]imidazole with furfural and 5-bromo- and 5-nitrofurfural. The methylation, nitration, and acetylation of the compounds obtained were studied, and the replacement of the bromine atom in the furan ring by a nitro group was also investigated.

Synthesis and transformations of 2-(2-furyl)- and 2-[β-(2-furyl)vinyl] phenanthr [9,10]imidazoles

The corresponding 2-(2-furyl)- and 2-[β-(2-furyl)vinyl] phenanthr[9,10]imidazoles were obtained by the condensation of 9,10 phenanthrenequinone with furfural, β-(2-furyl)acrolein, and their 5-bromo and 5-nitro derivatives in the presence of ammonium acetate in glacial acetic acid. Their metallation, acetylation, nitration, and replacement of halogen by a nitro group were studied.

Research on the chemistry of 2-hetarylbenzimidazole. 3. Reaction of 1-methyl-2-(5?-methyl-2?-hetaryl) benzimidazoles with electrophilic reagents

A number of new derivatives of 1-methyl-2-(5′-methyl-2′-hetaryl)benzimidazole were synthesized by electrophilic substitution. The substituent enters the β position of the 4′-hetaryl ring. A furan ring that contains a methyl group in the 5′ position undergoes profound destructive oxidation under the influence of acetyl nitrate. Depending on the conditions, bromination leads to the formation of bromo derivatives that are substituted in the benzene or hetaryl ring.

Synthesis of 2-phenyl-3-(2-furyl) — and 2-phenyl-3-[β-(2-furyl)vinyl]-1,2-dihydro-naphtho[1,2-d]-1,2,4-triazines

The corresponding 2-phenyl-3-(2-furyl)- and 2-phenyl-3-[β-(2-furyl)vinyl]-1,2-dihydronaphtho-[1,2-d]-1,2,4-triazines were obtained by heating Schiff bases [prepared by reaction of 1-(phenyl-azo)-2-aminonaphthalene with furfural,β -(2-furyl)acrolein, and their 5-bromo and 5-nitro derivatives] in glacial acetic acid.

Synthesis and transformations of 2-(2-furyl)- and 2-[β-(2-furyl)vinyl]imidazo[4,5-f]quinolines

The corresponding 2-(2-furyl)- and 2-[β-(2-furyl)vinyl]imida zo[4,5-f]quinolines were obtained by condensation of 5,6-diaminoquinoline and 5-amino-6-rnethylaminoquinoline with furfural, furylacrolein, and their 5-bromo and 5-nitro derivatives and also with the hydrochlorides of imino esters of furancarboxylic and furylacrylic acids. Alkylation, acetylation, nitration, and substitution of the halogen in the furan ring by a nitro group were studied.