N. Nishiwaki, Masataka Hisaki, Masaki Ono
Sep 5, 2009
Citations
0
Influential Citations
9
Citations
Journal
Tetrahedron
Abstract
A new preparative method for pyrido[2,3-b][1,4]oxazines from 6-substituted 3-nitro-2-pyridones is demonstrated. This method consists of two steps: O-alkylation and reductive cyclization. In the former step, the bulkiness of both starting nitropyridones and C2 reagents is found to be essential for avoiding N-alkylation, which undergoes O-alkylation efficiently. The subsequent reductive cyclization affords pyridoxazines with carbon substituents at both the 2- and the 6-positions that have not been available.