Synthesis of 2-Aryl-4H-3,1-Benzoxazin-4-ones: A Class of alpha-Chymotrypsin Inhibitors

Twenty one derivatives of 2-aryl-4H-3,1-benzoxazin-4-one were synthesized and their potential therapeutically significance and structure activity relationship were tested against alpha-chymotrypsin. Majority of synthesized compounds showed significant in vitro a-chymotrypsin inhibitory properties having IC50 values in the range of 5.42 +/- 1.66-41.27 +/- 1.33 mu M, whereas standard inhibitor chymostatin have IC50 value 7.13 +/- 1.06 mu M. In the present series compounds 2-(2-fluorophenyl)-4H-3,1-benzoxazin-4-one (3h), 2-(2-bromophenyl)-4H-3,1-benzoxazin-4-one (3n) and 2-(1-naphthyl)-4H-3, 1-benzoxazin-4-one (3t) with IC50 values 7.22 +/- 0.75, 6.99 +/- 0.29 and 5.42 +/- 1.66 mu M, respectively were found to be most active members of series, even better than standard inhibitor alpha-chymostatin.