Evaluation of Some Anti-Inflammatory Pyrimidobenzimidazoles Synthesized via Novel Tin(II) Chloride-Hydrochloric Acid Assisted Water Addition and Reduction of 4,4,6-Trimethyl-1-(2-nitroaryl)-1,4-dihydropyrimidine-2(3<i>H</i>)- thiones
作者:Sham M. Sondhi、Archana Magan、Rajesh Sahu、Vijendra K. Mahesh、Rakesh Shukla、Gyanendra K. Patnaik
DOI:10.1055/s-1994-25667
日期:——
4,4,6-Trimethyl-l-(2-nitroaryl)-1,4-dihydropyrimidine-2(3H)-thiones (Ia-c) on reduction with Al/Hg amalgam gave 1-(2-aminoaryl)-4,4, 6-trimethyl-1,4-dihydropyrimidine-2(3H)-thiones (IIa-c) . The reduction of 4,4,6-trimethyl-1-(2-nitroaryl or 4-nitrophenyl or phenyl)-1, 4-dihydropyrimidine-2(3H)-thiones (Ia-f) with SnCl2/HCl gave 1-(2-aminoaryl or 4-aminophenyl or phenyl)-6-hydroxy-4,4, 6-trimethyl-1,4,5,6-tetrahydropyrimidine-2(3H)-thiones (IIIa-f). 1-(2-Aminoaryl)-6-hydroxy-4,4,6-trimethyl-1,4,5,6-tetrahydropyrimi-dine-2(3H) -thiones (IIIa-d) undergo cyclization to give pyrimido[3,4-a]benzimidazoles IVa-d when refluxed for 2 h in ethanol using a catalytic amount of sulfuric acid. Pyrimido[3,4-a]benzimidazole IVa undergoes S-alkylation when treated with ethylbromo-acetate to give S-alkylated pyrimido[3,4-a]benzimidazole VI. 1-(4-Aminophenyl)-6-hydroxy-4,4,6-trimethyl-1,4,5,6-tetrahydro-pyrimidine-2 (3H)-thione (IIIe) on stirring at r. t. with ethanol and a catalytic amount of sulfuric acid gave 1-(4-aminophenyl)-6-ethoxy-4,4, 6-trimethyl-1,4,5,6-tetrahydropyrimidine-2(3H)-thione (V). Compounds IIIa,b,c, IVa-d and VI were tested for anti-inflammatory activity, IIIa,b,c, IVa and VI were inactive, whereas IVb and IVc showed 14% and 34% activity, respectively, at 100 mg/kg p. o. Compound IVc showed 28% activity at 25 mg/kg p. o. which is almost equipotent to phenylbutazone (30 mg/kg p. o.).
4,4,6-三甲基-1-(2-硝基芳基)-1,4-二氢嘧啶-2(3H)-硫代物(Ia-c)用铝/汞齐还原后得到 1-(2-氨基芳基)-4,4,6-三甲基-1,4-二氢嘧啶-2(3H)-硫代物(IIa-c)。用 SnCl2/HCl 还原 4,4,6-三甲基-1-(2-硝基芳基或 4-硝基苯基或苯基)-1,4-二氢嘧啶-2(3H)-硫酮 (Ia-f),得到 1-(2-氨基芳基或 4-氨基苯基或苯基)-6-羟基-4,4,6-三甲基-1,4,5,6-四氢嘧啶-2(3H)-硫酮 (IIIa-f)。 1-(2-氨基芳基)-6-羟基-4,4,6-三甲基-1,4,5,6-四氢嘧啶-2(3H)-硫酮(IIIa-d)在乙醇中使用一定量的硫酸催化回流 2 小时后发生环化反应,生成嘧啶并[3,4-a]苯并咪唑 IVa-d。嘧啶并[3,4-a]苯并咪唑 IVa 经溴乙酸乙酯处理后发生 S-烷基化反应,得到 S-烷基化的嘧啶并[3,4-a]苯并咪唑 VI。 1-(4-氨基苯基)-6-羟基-4,4,6-三甲基-1,4,5,6-四氢嘧啶-2(3H)-硫酮 (IIIe)在乙醇和一定量的硫酸催化下搅拌反应,得到 1-(4-氨基苯基)-6-乙氧基-4,4,6-三甲基-1,4,5,6-四氢嘧啶-2(3H)-硫酮 (V)。化合物 IIIa、b、c、IVa-d 和 VI 进行了抗炎活性测试,IIIa、b、c、IVa 和 VI 没有活性,而 IVb 和 IVc 在 100 毫克/千克剂量时分别显示出 14% 和 34% 的活性,化合物 IVc 在 25 毫克/千克剂量时显示出 28% 的活性,几乎等同于苯基丁氮酮(30 毫克/千克剂量)。