The present study was aimed at the synthesis and evaluation of a new series of benzo[4,5]imidazo[1,2-a]pyrimidine having a methylsulfonyl group as COX-2 (cyclooxygenase-2) inhibitor pharmacophore. Molecular modeling studies were performed using the Autodock program, and the results demonstrated that methylsulfonyl pharmacophore was adequately placed into the COX-2 active site. The in vitro and in vivo COX-2 inhibitory effects were also evaluated. In the in vitro assay, all newly synthesized compounds showed moderate to good selectivity for the inhibition of the COX-2 enzyme. However, compound 2-(4-(methylsulfonyl) phenyl)-4-phenylbenzo[4,5]imidazo[1,2-a]pyrimidine (5a) showed the highest COX-2 inhibitory effect (IC₅₀: 0.05 μM) even more than celecoxib as the reference drug (IC₅₀: 0.06 μM). For the in vivo study, the writing reflex test was used, and the results indicated that all synthesized compounds had well dose-dependent anti-nociceptive activity. The in vivo evaluation also showed that compound 2-(4-(methylsulfonyl)phenyl)-4-(p-tolyl)benzo[4,5]imidazo[1,2-a]pyrimidine (5d) had the highest activity in the writing reflex test (ED₅₀: 5.75 mg/kg). In addition, the cytotoxicity effects of the synthesized compounds were tested on MCF-7 breast cancer cells, and all compounds showed considerable inhibitory results.

本研究旨在合成和评价一系列具有甲基磺酰基的苯并[4,5]咪唑并[1,2- a ]嘧啶作为COX-2（环氧合酶-2）抑制剂药效团。使用 Autodock 程序进行了分子建模研究，结果表明甲基磺酰基药效团已充分置于 COX-2 活性位点。还评估了体外和体内 COX-2 抑制作用。在体外试验中，所有新合成的化合物对 COX-2 酶的抑制作用表现出中等到良好的选择性。然而，化合物 2-(4-(methylsulfonyl) phenyl)-4-phenylbenzo[4,5]imidazo[1,2- a ]pyrimidine ( 5a ) 显示出最高的 COX-2 抑制作用 (IC ₅₀: 0.05 μM) 甚至超过作为参考药物的塞来昔布 (IC ₅₀ : 0.06 μM)。对于体内研究，使用了书写反射测试，结果表明所有合成的化合物都具有良好的剂量依赖性抗伤害感受活性。体内评价还表明化合物2-(4-(甲基磺酰基)苯基)-4-(对甲苯基)苯并[4,5]咪唑并[1,2- a ]嘧啶( 5d )在书写反射测试 (ED ₅₀ : 5.75 mg/kg)。此外，合成的化合物对MCF-7乳腺癌细胞的细胞毒性作用进行了测试，所有化合物均显示出相当大的抑制效果。