Synthesis of Novel 6,7,8,9-Tetrahydro-5H-5-hydroxyphenyl-2-benzylidine-3-substituted Hydrazino Thiazolo (2,3-b) Quinazoline as Potent Antinociceptive and Anti-inflammatory Agents

A series of 6,7,8,9-tetrahydro-5H-5-hydroxyphenyl-2-benzylidine-3-substituted hydrazino thiazolo (2,3-b) quinazolines have been synthesized to meet the structural requirements essential for anti-inflammatory and antinociceptive properties The synthesized series of heterocycles, 6,7,8,9-tetrahydro-5H-5-hydroxyphenyl-2-benzylidine-3-substituted hydrazino thiazolo (2,3-b) quinazoline by the reaction of 6,7,8,9-tetrahydro-5H-5-hydroxy phenyl thiazolo (2,3-b) quinazolin-3(2H)-one with appropriate hydrazine hydrate and ketones/aldehydes in the presence of anhydrous sodium acetate and glacial acetic acid as presented in Scheme 1 Their antinociceptive activity were evaluated by tail-flick technique, anti-inflammatory was evaluated by carrageenan-induced paw edema test and their ulcerogenicity index determined by reported protocol The compounds exhibited the lowest ulcer index (0 51 +/- 1 63, 0 48 +/- 1 28 and 0 50 +/- 1 53, respectively The 6,7,8,9-tetrahydro-5H-5-hydroxy phenylhydroxy-2-benzylidine-3-(N'-3-pentylidenehydrazino) thiazolo (2,3-b) quinazoline and 6,7,8,9-tetrahydro-5H-5-hydroxy phenyl-2-benzylidine-3-(N'-2-pentylidene-hydrazino) thiazolo (2,3-b) quinazoline exhibited the most potent antinociceptive and anti-inflammatory activities