First Synthetic Method for the Preparation of 6-Unsubstituted-2,3-dihydro-1,3-oxazin-4-ones

Abstract

The first synthetic pathway to synthesize 6-unsubstituted-2,3-dihydro-1,3-oxazin-4-ones is described. The α-formylation of the starting amide and the cyclization of the α-formylamide with a desired aldehyde under acidic conditions gave compounds 5a − h (R = nPr, iPr, cPr, cHex, Ph, CH2Ph, nHex, and R1 = H, Me). This strategy was used with little modification for the preparation of new monocyclic organic nitrates such as 2a − c (2a (R = Ph, R1 = H, and R2 = H), 2b (R = Ph, R1 = H, and R2 = Me), and 2c (R = H, R1 = Ph, and R2 = H).