Nucleosides 7(9): synthesis, structure, and biological activity of new 6-arylidenamino-2-thio- and 2-benzylthiopyrimidine N-nucleosides.

The condensation of 6-amino-2-thioxo-2,3-dihydro-1H-pyrimidine-4-one [compound (1)] with aromatic aldehydes (2) afforded azomethine derivatives (3). The formed azomethines underwent glycosidation with α-acetobromoglucose (4) to form the corresponding pyrimidine N-glycosides (6) and not S-glycosides (5). The interaction of (3) with 1-O-acetyl-2, 3, 5-tri-O-benzoyl-β-D-ribofuranose (8) afforded the corresponding pyrimidine N-riboside (10) and not S-riboside (9). Deacetylation and debenzoylation of each of (6) and (10) by using methanolic sodium methoxide afforded the corresponding free N-nucleosides (7) and (11), respectively. Next, the reaction of 2-benzylthio-6-benzylidenaminouracil (13) with (4) and (8) did not yield the corresponding protected N-nucleosides (14) and (17), whereas it afforded (15) and (18), respectively. The latter compounds (15) and (18) were stirred in methanolic sodium methoxide to yield the corresponding free N-nucleosides (16) and (19), respectively. The structures of products have been elucidated and reported and also some of the products were screened for their antimicrobial activity. Graphical Abstract: