Click Chemistry Based Synthesis of Novel Architectures Bearing Sugar Unit at the Pyridothienopyrimidines

Novel conjugates of pyridothienopyrimidinones and carbohydrates or other moieties linked by 1,2,3‐triazoles were synthesized. After establishing the pyridothienopyrimidone ring systems by ring closure, propargyl group was introduced by O‐alkylation or N‐alkylation. Cu‐catalyzed cycloaddition of the propargyl product with azido group gave the corresponding 1,2,3‐triazoles in high yields. A remarkable case of the catalyzed ring closure to build a pyrimidinone moiety with two diastereomers was observed. Theoretical calculations were performed on the studied diastereomers, and it was found that the S‐isomer is more stable than the corresponding R‐isomer by about 2 kcal/mol.