2-Alkyl-5-imino-1-benzopyrano[3,4-c]pyridin-4(3H,5H)-ones and related compounds from reaction of 3-carbamoyl-2-iminochromens with methyl ketones
Abstract
The base-catalysed condensation of 3-carbamoyl-2-iminochromens with methyl ketones yields 2-alkyl-5-imino-1-benzopyrano[3,4-c]pyridin-4(3H,5H)-ones, 2-alkyl-1-benzopyrano[3,4-c]pyridin-4(3H),5-diones, and 3-cyano-4-(2-hydroxyphenyl)-6-methyl-3,4-dihydropyridin-2-ones (which exist in two tautomeric forms).