Synthesis of some condensed benzofurans

The condensation of O-phenylhydroxylamine (Ia) with tetrahydro-4-thiopyrone, 1-methyl-4-piperidone (IIb), 1,2,5-trimethyl-4-piperidone, and 4-thiochromanone and of O-(4-tolyl)-hydroxylamine with IIb was used to synthesize the corresponding benzofuran derivatives (IIIa-e), from which IIIa and IIIb were obtained by deamination of 8-amino-3,4-dihydro-1H-thiopyrano-4,3-b]benzofuran and 2-methyl-8-amino-1,2,3,4-tetrahydrobenzofuro3,2-c]pyridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 740–742, June, 1972.