Reaction of 4-aminoimadazo[4.5-c]pyridin-2-ones with α-bromomethylketones

The reactions of 4-amino derivatives of imidazo[4.5-c]pyridin-2-ones with -bromomethylketones have been studied. Depending on the nature of the reagents and the reaction conditions, either 5-acylmethyl salts of the starting amine or 2-substituted imidazo[4.5-c]imidazo[1,2-a]pyridin-8-ones can be obtained. The latter compounds are also easily obtained by treatment of the 5-acylmethyl salts with alkali.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 227–232, February, 1986.     

Preparation of 2-aryl-substituted imidazo[4,5-b]pyridines and imidazo[4,5-c]pyridines

It is proposed that sulfur be used as the oxidizing agent in the synthesis of 2-arylimidazopyridines from o-diaminopyridines and aromatic (heteroaromatic) aldehydes. Benzyl alcohols and benzylpyridinium salts can be used in place of aldehydes. 2-Phenylimidazopyridines are also formed in the thermal oxidation with sulfur of o-diaminopyridines with a benzyl substituent attached to the ring or exocyclic nitrogen atoms.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 639–645, May, 1987.     

Halogenation of imidazo[4,5-c]pyridinones

Unsubstituted imidazo[4, 5-c]pyridine does not react with chlorine, bromine, or iodine at room temperature or even upon heating to 160°C. The introduction of an oxo group activates the system such that halogenation proceeds readily. Imidazo[4, 5-c]pyridin-4-one gives 7-halo derivatives, while imidazo[4, 5-c]pyridin-2-ones give 4, 7-dihalo products.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1076—1081, August, 1994.