Abstract Some new 1-substituted-4-(4-nitrophenyl)-[1,2,4]triazolo[4,3- a ]quinazolin-5(4 H )-ones were synthesized and screened for their H 1 -antihistaminic activity. The structures of the newly synthesized compounds were confirmed by IR, 1 H NMR, and mass spectral data and purity of the compounds was determined by elemental analysis. Antihistaminic activity of synthesized compounds was determined by the protection against histamine-induced bronchospasm on conscious guinea pigs. Percentage protection data showed that all title compounds of the series show significant protection in the range of 68–71.56% when compared to reference drug chlorpheniramine maleate (70.17%). The sedative properties of the compounds were also evaluated and found to be negligible when compared to chlorpheniramine maleate.

中文翻译：

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1-取代-4-(4-硝基苯基)-[1,2,4]三唑并[4,3-a]喹唑啉-5(4H)-酮类新型抗组胺药的设计与合成

摘要 合成了一些新的1-取代-4-(4-硝基苯基)-[1,2,4]三唑并[4,3-a]喹唑啉-5(4 H )-ones并筛选了它们的H 1 -抗组胺活性。 . 新合成化合物的结构经IR、 1 H NMR确证，化合物的质谱数据和纯度通过元素分析确定。合成化合物的抗组胺活性是通过保护清醒的豚鼠免受组胺诱导的支气管痉挛来确定的。百分比保护数据显示，与参比药物马来酸氯苯那敏 (70.17%) 相比，该系列的所有标题化合物均显示出 68-71.56% 的显着保护。还评估了这些化合物的镇静特性，发现与马来酸氯苯那敏相比可以忽略不计。