On the reaction of 3,4‐dihydropyrimidones with nitric acid. Preparation and x‐ray structure analysis of a stable nitrolic acid

A series of substituted 3,4‐dihydro‐2‐pyrimidones (DHPMs) was reacted with nitric acid under different reaction conditions. Treatment of DHPMs with 50‐65% nitric acid at 0 °C led to the formation of the corresponding dehydrogenated 2‐pyrimidones in moderate to good yields. In contrast, reaction of one representative DHPM with 60% nitric acid at 50 °C led to an unusually stable nitrolic acid, involving a formal nitration, nitrosation, and dehydrogenation step. The molecular structure of this product was determined by X‐ray crystallographic analysis