Synthesis of 3-amino-6-methyl-4-phenylpyridin-2(1H)-one and its derivatives

A reaction of 2-cyanoacetamide with benzylideneacetone in DMSO containing potassium tert-butoxide was used to synthesize 3-cyano6-methyl-4-phenylpyridin-2(1.)-one, which was converted by acidic hydrolysis to 6-methyl-2-oxo-4-phenyl-1,2-dihydropyridine-3carboxamide.A Hofmann reaction of this compound in the presence of sodium hypobromite led to 3-amino-5-bromo-6-methyl4-phenylpyridin-2(1H)-one, while its treatment with calcium hypochlorite produced 5-methyl-7-phenyloxazolo[5,4-b]pyridin-2(1H)-one. The latter compound was converted by heating with alkali to 3-amino-6-methyl-4-phenylpyridin-2(1.)-one, which gave azomethine in a reaction with benzaldehyde, while N-acylated derivatives were obtained in reactions with acyl halides. The heating of N1, N2- bis(6-methyl2-oxo-4-phenyl-1,2-dihydropyridin-3-yl)oxalylamidein the presence of POCl3 allowed to obtain 5,5'-dimethyl-7,7'-diphenyl-2,2'-bis( oxazolo[5,4-b] pyridine).