Studies on Prototropic Tautomerism in Nitrogen Heterocyclic Compounds. I. The Mannich Reaction of 2(1H)-Pyridone and 3-Hydroxy-2(1H)-pyridone

Abstract

The Mannich reaction of 3-hydroxy-2 (1H)-pyridone, in which both a phenolic OH and a lactam NH are present in a molecule, was examined, and 3-hydroxy-6-piperidinomethyl-2(1H)-pyridone (IXa) and 3-hydroxy-4, 6-bis (piperidinomethyl)-2(1H)-pyridone (X) were obtained in 82 and 5% yields, respectively. The reaction of IXa with the cyclohexanone pyrrolidine enamine gave 4a, 7-dihydroxy-1, 2, 3, 4, 4a, 10a-hexahydrobenzo [b] indolizin-6 (10H)-one (XVI) in 82% yield.