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Synthesis and pharmacological investigation of novel 4‐(4‐Ethyl phenyl)‐1‐substituted‐4 H ‐[1,2,4]triazolo[4,3‐ a ]‐quinazolin‐5‐ones as new class of H 1 ‐antihistaminic agents
Author(s) -
Alagarsamy V.,
Parthiban P.,
Solomon V. Raja,
Dhanabal K.,
Murugesan S.,
Saravanan G.,
Anjana G. V.
Publication year - 2008
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570450312
Subject(s) - chemistry , chlorpheniramine maleate , aniline , yield (engineering) , electrophile , histamine , combinatorial chemistry , stereochemistry , medicinal chemistry , organic chemistry , pharmacology , chromatography , catalysis , medicine , materials science , metallurgy
A series of novel 4‐(4‐ethylphenyl)‐1‐substituted‐4 H ‐[1,2,4]triazolo[4,3‐ a ]quinazolin‐5‐ones were synthesized by the cyclization of 2‐hydrazino intermediate with various electrophile. The starting material 2‐hydrazino compound was synthesized from 2‐ethyl aniline by a new innovative route with improved yield. When tested for their in vivo H 1 ‐antihistaminic activity on conscious guinea pigs, all the test compounds significantly protected the animals from histamine induced bronchospasm. The compound II emerged as the most active compound of the series and it is more potent (73.93% protection) when compared to the reference standard, chlorpheniramine maleate (71% protection), it showed negligible sedation (10%) when compared to chlorpheniramine maleate (30%). Therefore compound II will serve as prototype molecule for further development as a new class of H 1 ‐antihistamines