Substituted 5,6-dihydrofuro[3,2-f]-1,2-benzisoxazole-6-carboxylic acids: high-ceiling diuretics with uricosuric activity

A series of substituted 5,6-dihydrofuro[3,2-f]-1,2-benzisoxazoles was prepared and evaluated for their saluretic and uricosuric properties. Pharmacological evaluation of the title compounds was carried out in mice, rats, dogs, and monkeys. The diuretic/saluretic nature of these compounds was observed in all species, whereas the uricosuric activity was best seen in the Cebus monkey. Evaluation of the enantiomers of 8-chloro-3-(o-fluorophenyl)-5,6-dihydrofuro [3,2-f]-1,2-benzisoxazole-6-carboxylic acid (15k) revealed that only the (+) enantiomer (29) displayed diuretic and saluretic activity, whereas both enantiomers possessed uricosuric activity. X-ray analysis showed that the (-) enantiomer (30) possesses the 2R configuration.