Thieno[2,3-d ]Pyrimidin-4-Ones. Part 2*. Condensation of 2,3- Disubstituted Thieno[2,3-d]Pyrimidin-4-Ones with Aldehydes
B. Zh. Elmuradov *
Organic Synthesis Department, Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent 100170, Uzbekistan
Kh. A. Bozorov
Organic Synthesis Department, Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent 100170, Uzbekistan
Kh. M. Shakhidoyatov
Organic Synthesis Department, Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent 100170, Uzbekistan
*Author to whom correspondence should be addressed.
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.
Keywords: Condensed thieno[2,3-d]pyrimidin-4-ones, electrophilic addition products, 9-arylidene derivatives, aldehydes, condensation