1, 3-Oxazines and Related Compounds. VIII. Reaction of 6-Methyl-2-phenyl-4H-1, 3-oxazin-4-one with Lactams and Their Derivatives

Abstract

6-Methyl-2-phenyl-4H-1, 3-oxazin-4-one (1) underwent initial attack of the anions of lactams (2), such as ε-capro-(2a), δ-valero-(2b), and γ-butyro-lactams (2c), at the 4-position of the ring to give the corresponding α-substituted lactams (3a-c). Reaction of 1 with N-trimethylsilyl derivatives (6a-c) of 2 in the presence of lithium diisopropylamide afforded the 2, 3-dihydro-4H-1, 3-oxazin-4-one derivatives (7a-c), respectively. Similar treatment of 1 with O-methyl derivatives (9a-c) of 2 yielded the corresponding bicyclic heterocycles (10a-c).