Studies on 6-[(dimethylamino)methylene]aminouracil: a facile one-pot synthesis of novel pyrimido[4,5-d]pyrimidine derivatives

Abstract The reactions of 6-[(dimethylamino)methylene]aminouracil 1 , with various heterocumulenes such as aryl isocyanates and isothiocyanates give rise to novel pyrimido[4,5- d ]pyrimidines in excellent yields, after elimination of dimethylamine from the (1:1) cycloadducts and tautomerisation. This procedure provides a convenient method for direct synthesis of pyrimido[4,5- d ]pyrimidine derivatives under thermal conditions.