Reactions of resorcinol with substituted 3,4-dihydro-2(1H)-pyrimidinethiones

A Condensation of Biginelli Products with 1,3‐Benzenediols: a Facile Access to Diastereomerically Pure Hexahydro‐5H‐chromeno[4,3‐d]pyrimidin‐5‐ones

“…Keywords: Biginelli products · 1,3-benzenediols · acidcatalyzed condensation · 2-thioxo-1,2, 3,4,4a,pyrimidin-5-ones…”

“…Motivated by these facts, our lab previously paid attention to reaction condensation of Biginelli products with 1,3‐benzenediols which can afford interesting heterocyclic compounds. It is known that the acid‐catalyzed reaction of dihydropyrimidine‐2‐thiones with resorcinols leads to corresponding 4‐aryl‐substituted hexahydropyrimidine‐2‐thiones, as mixtures of two diastereomers (Scheme , 1a ). The similar condensation of 4‐styryl‐dihydropyrimidine‐2‐thiones affords to spiro ([1] benzopyran‐2,4′‐(1′ H ) pyrimidine)‐2′‐(3′ H )‐thiones (Scheme , 1b ) or octahydrochromeno [3,2‐ i ] quinazoline‐2(1 H )‐thiones (Scheme , 1c ), is also usually associated with the formation of stereoisomers.…”