Regioselective synthesis of 7,8-dihydropyrrolo[1,2-a]pyrimidin-4(6H)-ones and 7,8-dihydropyrrolo[1,2-a]pyrimidin-2(6H)-ones

By Donghi, Monica; Pesci, Silvia; Summa, Vincenzo; Koch, Uwe; Spieser, Stephane; Gardelli, Cristina
From Synlett (2010), (2), 235-239. Language: English, Database: CAPLUS, DOI:10.1055/s-0029-1218566

Annulated analogs e.g., I, II of 5,6-dihydroxypyrimidine-4-carboxylate ester and 5,6-dihydroxypyrimidine-4-carboxylamide were synthesized. The intermediary homoallylic amines were subjected to a ring-closure reaction under different reaction conditions. A notable pH-dependency of the ring closure leading to regioisomeric tetrahydropyrrolo[1,2-a]pyrimidines was obsd. Treatment with dimethyldioxirane and base led to 3-hydroxy-4-oxo-4,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidines while m-chloroperbenzoic acid or NBS afforded 3-hydroxy-2-oxo-2,6,7,8-tetrahydropyrrolo[1,2-a]pyrimidines.