Inhibition of rat passive cutaneous anaphylaxis by 3-(tetrazol-5-yl)quinolines

Quinoline-3-carboxylic acid (3) was found to have weak oral activity in the rat passive cutaneous (PCA) assay. In an effort to increase activity, the synthesis of structurally related compounds was initiated. This led to substituted 3-(tetrazol-5-yl)quinolines, some of which are equal in potency, when given orally, to doxantrazole. Further work resulted in the synthesis of 4-oxoquinolines, one of which, 8-chloro-1,4-dihydro-4-oxo-3-(tetrazol-5-yl)quinoline (132), is 33-fold more active than disodium cromoglycate (ip) and 32-fold more active than doxantrazole (po).