ChemInform Abstract: Studies on Fused Pyrimidine Derivatives. Part 6. Characterization of a Perhydro‐5,6‐di(methylene)‐2,4‐dioxopyrimidine Intermediate and Its Cycloaddition Reactions Leading to Quinazoline Derivatives.

Abstract The dioxopyrimidinecarbaldehyde hydrazone (I) reacts with N‐methylmaleimide (II) to form the cycloadducts (III).