A new approach to the pyrrolo[3,4-d] pyrimidine system via tandem Staudinger/aza-Wittig reaction of 5-acyl-4-azidomethyl-3,4-dihydropyrimidin-2(1H)-ones

A novel access to pyrrolo[3,4-d]pyrimidine scaffold via tandem Staudinger/intramolecular aza-Wittig reaction of 5-acyl-4-(1-azidoalkyl)-3,4-dihydropyrimidin-2(1H)-ones promoted by PPh₃ was developed. Synthesis of the starting pyrimidinones involved the reaction of readily available N-[(2-azido-1-tosyl)alkyl]ureas with Na enolates of benzoylacetone or acetylacetone followed by acid-catalyzed dehydration of the resulting products without their isolation.