Preparation of substituted 1,3-dihydro-2H-imidazo[4,5-c]pyridin-2-ones

摘要

A new synthetic route to 6-substituted-imidazo[4,5-c]pyridin-2-ons from 4-aminopyridine has been investigated. 4-Aminopyridine protected as alkyl carbamates were nitrated with dinitrogen pentoxide to the corresponding methyl, i-propyl and t-butyl 3-nitropyridin-4-yl carbamates (5a-c) in 51-63 % yields. Attempts to substitute these in the 6-position by the ONSH and the VNS techniques succeeded with butylamine and the t-butyl carbamate 9. From the methyl or t-butyl 3-nitropyridin-4-yl carbamates 5a, 5c 1,3-dihydro-2H-imidazo[4,5-c]pyridin-2-one (1) was formed in 73 and 39 % yields, respectively. t-Butyl 6-N-butylamin-3-aminopyridin-4-yl carbamate (6) gave 6-butylamino-1,3-dihydro-2H-imidazo[4,5-c]-pyridin-2-one (7) in 53 % yield. [References: 46]