METHOD FOR PREPARING 1,2,3,4-TETRAHYDROPYRIDO[1,2-A]BENZIMIDAZOLES Russian patent published in 2021 - IPC C07D471/04 

FIELD: organic chemistry.

SUBSTANCE: invention relates to a method for preparing 1,2,3,4-tetrahydropyridobenzimidazoles of general formula (1), where R = a) H, b) CF₃, c) CN, d) NO₂, e) Cl, in which reductive cyclization of N- (2-nitroaryl) piperidines are carried out in 8% hydrochloric acid using an electric current in an electrolyzer without a diaphragm in a galvanostatic mode at a temperature of 40°C on a lead cathode, while passing a 2.2 F charge through the electrolytic cell for 0.25 h, with a current of 0.5 A, using a graphite anode, the target products are isolated after processing the reaction mixture with ammonium hydroxide, extraction with chloroform and distillation of the latter until a dry precipitate is obtained.

EFFECT: resource-saving, environmentally friendly method for the synthesis of 1,2,3,4-tetrahydropyridobenzimidazoles with a high yield has been developed, which reduces the synthesis time and the synthesis temperature.

1 cl, 5 ex