Synthesis and Anti Bacterial and Anti-ulcer Evaluation of New S-mannich Bases of 4,6-diaryl-3,4-dihydropyrimidin-2(1H)-thiones
作者:Venkateshwarlu Kodhati、Malla Reddy Vanga、Narsimha Reddy Yellu
DOI:10.5012/jkcs.2013.57.2.234
日期:2013.4.20
The synthesis of title compounds were accomplished by synthetic sequence shown in Scheme 1. Chalcones on cyclocondensation with thiourea in ethanol and potassium hydroxide under reflux yielded the respective dihydropyramidin-2(1H)-thiones. Each of the dihydropyrimidin thiones was, then subjected to the Mannich condensation in alkaline medium using three different secondary amines, viz., dimethylamine, diethylamine and morpholine to obtain a new series of S-Mannich bases. All the synthesised compounds ($C_1-C_15}$) were evaluated for their antiulcer and antibacterial activities. Compounds $C_4$, $C_5$, $C_6$, $C_14}$ and $C_15}$ exhibited relatively more potent antiulcer activity but not comparable to the standard; Omeprazole, while $C_1$, $C_2$, $C_3$ and $C_13}$ were moderate in activity at 100 mg/kg p.o. All the compounds ($C_1-C_15}$) showed mild to moderate activity against both Gram-positive (S.aureus, L.delbrueckii) and Gram-negative (P.vulgaris, E.coli) bacteria. Amongst the compounds tested, only $C_6$, $C_9$, $C_12}$ and $C_15}$ were found to be potent.
标题化合物的合成是通过方案1所示的合成序列完成的。香豆素与硫脲在醇和氢氧化钾的回流条件下环缩合,得到了相应的二氢嘧啶-2(1H)-硫酮。然后,将每个二氢嘧啶硫酮置于碱性介质中,使用三种不同的二级胺(即二甲胺、二乙胺和哌啶)进行曼尼希缩合,以获得一系列新的S-曼尼希碱。所有合成的化合物(C1-C15)均被评估其抗溃疡和抗菌活性。化合物C4、C5、C6、C14和C15表现出相对更强的抗溃疡活性,但与标准药物奥美拉唑相比仍显不足,而C1、C2、C3和C13在100 mg/kg口服给药时表现出中等活性。所有化合物(C1-C15)对革兰阳性菌(S.aureus,L.delbrueckii)和革兰阴性菌(P.vulgaris,E.coli)均显示出轻至中等活性。在测试的化合物中,只有C6、C9、C12和C15被发现具有较强的活性。