Certain 3,4-dihydro 4-oxospiro [2h-1 benzopyrans] useful for treating

Abstract

A novel heterocyclic compound capable of lowering the uric acid levels in plasma and urine having the formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are independently hydrogen, lower alkyl, phenyl or substituted phenyl, or R.sup.1 and R.sup.2 may form a four- to eight-membered carbon ring together with the carbon atom to which they are attached; R.sup.3 is hydrogen or lower alkyl; R.sup.4 is one or two radicals selected from a group consisting of hydrogen, halogen, nitro, lower alkyl, phenyl, substituted phenyl, --OR.sup.5 and --SO.sub.2 NR.sup.6 R.sup.6' ; R.sup.5 is hydrogen, lower alkyl, phenyl-substituted lower alkyl, carboxymethyl or ester thereof, hydroxyethyl or ether thereof, or allyl; R.sup.6 and R.sup.6' are independently hydrogen or lower alkyl; R.sup.7 is hydrogen or a pharmaceutically active ester-forming group; A is a straight or branched hydrocarbon radical having one to five carbon atoms; B is halogen, oxygen, or dithiolane; Y is oxygen, sulfur, nitrogen or substituted nitrogen; Z is oxygen, nitrogen or substituted nitrogen; dotted line represents the presence or absence of a single bond.