METHOD OF SYNTHESIS OF PYRIDO [1,2-a]IMIDAZO[4,5-f]BENZIMIDAZOLE AND ITS DERIVATIVES Russian patent published in 2018 - IPC C07D471/14 

FIELD: chemistry.

SUBSTANCE: invention relates to the method of obtaining pirido [1,2-a]imidazo[4,5-f]benzimidazole and its derivatives, which includes the stages of nitration of 7-nitropirido [1,2-a]benzimidazole KNO₃ in concentrated sulfuric acid, the recovery of 7,8-dinitropirido [1,2-a]benzimidazole TiCl_3, and the annellation of imidazole cycle to benzene fragment of pirido [1,2-a]benzimidazole. The reaction of 7-nitropyrido [1,2-a]benzimidazole with KNO₃ is carried out at a temperature of 25°C and a molar ratio of 7-nitropyrido[1,2-a]benzimidazole : KNO₃=1:1.1 for 1 hour, the recovery of the alcohol solution of 7,8-dinitropyrido[1,2-a]benzimidazole is carried out with 15% solution of titanium chloride (III) in 10% hydrochloric acidand a molar ratio of 7,8-dinitropyrido[1,2-a]benzimidazole : TiCl₃=1:15 at 40°C for 0.5 h, the condensation of pyrido[1,2-a]benzimidazole-7,8-diamine with aliphatic acids is carried out at a temperature of 100°C and a molar ratio of pyrido[1,2-a]benzimidazole-7,8-diamine: aliphatic acid=1:10 for 1 hour in the presence of catalytic amounts of HCl.

EFFECT: method of obtaining the specified connection and its derivatives, allowing to reduce the cost of synthesis, to reduce the time and temperature of the process and to increase the yield of the desired product.

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