Thieno[2,3-d ]Pyrimidin-4-Ones. Part 2*. Condensation of 2,3- Disubstituted Thieno[2,3-d]Pyrimidin-4-Ones with Aldehydes

Abstract

The reactions of 2,3-tri-,-tetramethylene-7,8–dihydro-6Н–thieno[2,3-d]pyrrolo[1,2-a] pyrimidine-4-ones (1a,b) and 2,3-dimethyl-,-tri-,-tetra-,-pentamethylene-6,7,8,9-tetrahydropyrido[1,2-a]thieno[2,3-d]pyrimidine–4-ones (4a-d), containing active methylene groups in positions 8 or 9, with aromatic aldehydes under acidic and alkaline conditions go depending on reaction conditions and nature of aromatic aldehydes with the formation of new (±)-(4-nitrophenyl) (2,3-tri, tetramethylene-7,8-dihydropyrrolo[1,2-a]thieno[2,3-d] pyrimidine-4-one-8-yl) methanol’s (2,3), 9-arylidene derivatives (5a-e – 8a-e) and (±) - (4 - nitrophenyl) (2,3-tetramethylene-6,7,8,9- tetrahydropyrido[1,2-a]thieno[2,3-d]pyrimidine–4–one-9-yl)methanol (9). If aldehydes with electron-withdrawing (nitro) group are used, the reaction can be stopped at a stage where the products of electrophilic addition reactions are racemates, i.e. containing asymmetric carbon atom in position 8 or 9, and if aromatic aldehydes with electron-donating substituent are used 9-arylidene derivatives are formed exclusively.