Thiazole derivatives, their preparation and their use in the treatment

Abstract

Compounds of formula (I): ##STR1## in which: R.sup.1 and R.sup.2 are independently hydrogen, alkyl, aliphatic hydrocarbon groups having one or two carbon-carbon double or treble bonds, cycloalkyl, aryl, substituted aryl, aralkyl, substituted aralkyl, alkanoyl, alkenyol, cycloalkylcarbonyol, arylcarbonyl, substituted arylcarbonyl, arylalkanoyl, substituted arylalkanoyl, arylalkenoyl, substituted arylalkenoyl, alkoxycarbonyl, aryloxycarbonyl, substituted aryloxycarbonyl, aralkyloxycarbonyl, substituted aralkyloxycarbonyl, optionally substituted carbamoyl or thiocarbamoyol, alkylsulfonyl, haloalkylsulfonyl, arylsulfonyl, substituted arylsulfonyl, alkylthio, arylthio and substituted arylthio, or R.sup.1 and R.sup.2, together with the nitrogen atom to which they are attached, form a nitrogen-containing heterocyclic group; one of R.sup.a and R.sup.b is hydrogen, alkyl or halogen, and the other of R.sup.a and R.sup.b is a group of formula (II): ##STR2## R.sup.4 is hydrogen, carboxy, protected carboxy or optionally substituted carbamoyl; R.sup.5 is hydrogen, or carboxyalkyl or protected carboxyalkyl in which the alkyl part is C.sub.1 -C.sub.6 ; n=0, 1 or 2; X is oxygen or sulfur; are useful in the treatment of the complications attendant upon diabetes and may be prepared by condensation of a thiazolidine or rhodanine compound with a compound corresponding to the remainder of the molecule of the compound of formula (I).