反应详情

Reaction of 4-chloropyridone (XXXXII) with an aryl halide, such as benzyl bromide in benzene and in the presence of Ag2CO3 as described in Scheme 13 (Smith A. M.; et al. J. Med. Chem. 36, 8, 1993) and at temperature ranges of 30-80° C. afforded the corresponding 2-benzyloxypyridine (XXXXVII). This was coupled with an arylboronic acid, ArB(OH)2 under palladium-catalyzed conditions to give (XXXXIX). The benzyloxy group can be removed by treatment with a strong acid, such as trifluoroacetic, triflic, sulfuric, HCl, etc. to give pyridone (L). This was converted to the 2-halopyridine with the action of POX3, PX5 or the corresponding triflate, tosylate or mesylate, which was displaced with a primary amine RNH2 to give (LI). The nitro group was reduced under conditions described in scheme 13 and the aminopyridine was cyclized to the imidazolo[4,5-b]pyridine (LII) under conditions described in scheme 13.

1. customas described in Scheme 13 (Smith A. M.; et al. J. Med. Chem. 36, 8, 1993) and at temperature ranges of 30-80° C.