Reaction of 2‐dimethylaminomethylene‐1,3‐diones with dinucleophiles. III. Synthesis of 5‐acylpyrimidines and 7,8‐dihydroquinazolin‐5(6H)‐ones

The reaction of open‐chain and cyclohexane sym‐2‐dimethylaminomethylene‐1,3‐diones with amidines and guanidine in refluxing ethanol gave, generally in good yields, a series of 5‐acylpyrimidines and 7,8‐dihydroquinazolin‐5(6H)‐ones, respectively. With formamidine (and in part acetamidine), 2‐formylimino‐1,3‐diones were formed in general, as sole products or mixtures with the corresponding pyrimidines or dihydroquinazolinones.