Open Access 4-(3-Methoxyphenyl)-1-substituted-4H-[1,2,4]triazolo[4,3-a]quinazolin-5- ones: new class of H1-antihistaminic agents

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A series of 1-substituted-4-(3-methoxyphenyl)-4H-[1,2,4]triazolo[4,3-a]quinazolin-5-ones were synthesized by the cyclization of 2-hydrazino-3-(3-methoxyphenyl)-3H-quinazolin-4-one with various electrophile. The starting material 2-hydrazino-3-(3-methoxyphenyl)-3H-quinazolin-4-one was synthesized from 2-methoxy aniline by an innovative route. Title compounds were tested for their in vivo H1-antihistaminic activity on guinea pigs; all the tested compounds protected the animals from histamine induced bronchospasm significantly. Compound 1-methyl-4-(3-methoxyphenyl)-4H-[1,2,4]triazolo[4,3-a]quinazolin-5-one (II) emerged as the most active compound of the series and was more potent (72.76%) than the reference standard chlorpheniramine maleate (71%). Compound II showed negligible sedation (10%) when compared to chlorpheniramine maleate (25%). Hence it could serve as prototype molecule for further development as a new class of H1-antihistaminic agents.

Document Type: Research Article


Affiliations: 1: Medicinal Chemistry Research Laboratory, MNR College of Pharmacy, Sangareddy, 502 294, India, Email: 2: Department of Pharmaceutical Chemistry, Patel College of Pharmacy, Bhopal, India 3: Medicinal Chemistry Research Laboratory, MNR College of Pharmacy, Sangareddy, India 4: Medicinal & Process Chemistry Division, Central Drug Research Institute, Lucknow, India

Publication date: January 1, 2009

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  • Pharmazie is one of the world's leading pharmaceutical journals. As a peer-reviewed scientific journal, DiePharmazie is regularly indexed in Current Contents/Life Sciences, Excerpta Medica, Analytical Abstracts, International Pharmaceutical Abstracts, Beilstein Current Facts in Chemistry, Chemical Engineering and Biotechnology Abstracts (CEABA) and Science Citation Index.
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