Abstract
A series of pyrazolo[1,5-
a]pyrimidine, triazolo[1,5-
a]pyrimidine, and pyrimido[1,2-
a]benzimidazole ring systems incorporating phenylsulfonyl moiety were synthesized via the reaction of 3-(
N,N-dimethylamino)-1-aryl-2-(phenylsulfonyl)prop-2-en-1-one derivatives
2a,
b with appropriate nitrogen nucleophiles. The analgesic and anti-inflammatory activities of the newly synthesized compound were investigated in vivo. 3-Bromo-2-phenyl-6-(phenylsulfonyl)-7-(4-methylphenyl)pyrazolo[1,5-
a]pyrimidine (
5e) was found to have an excellent analgesic activity in comparison with indomethacin as a reference drug, while the highest anti-inflammatory effect was observed in the case of 2-(4-bromophenyl)-6-(phenylsulfonyl)-5-(4-methylphenyl)pyrazolo[1,5-
a]pyrimidine (
5d). From the structure–activity relationship (SAR) point of view, the analgesic/anti-inflammatory activity of pyrazolo[1,5-
a]pyrimidine derivatives was found to be much higher than triazolo[1,5-
a]pyrimidine and pyrimido[1,2-
a]benzimidazole derivatives.