Substituted thiadiazolines as inhibitors of central nervous system carbonic anhydrase

A series (24-30) of substituted thiadiazolines was synthesized and tested for in vitro carbonic anhydrase inhibition and for protective ability against pentylenetetrazole-induced convulsions. ED50 (pentylenetetrazole protection), TD50, and LD50 values are reported for each compound. With the exception of 30, all compounds approximated the model compound methazolamide as in vitro carbonic anhydrase inhibitors. Several of the compounds produced extended protection against pentylenetetrazole-induced convulsions. Ring methoxy substitution in the ortho position appeared to produce maximum activity.