Rhodanine derivatives, process for their preparation, and aldose

Abstract

The rhodanine derivatives of the general formula: ##STR1## [wherein (I) R.sup.1 and R.sup.2 are taken together to represent a tetramethylene or pentamethylene group; (II) R.sup.1 represents a hydrogen atom, and R.sup.2 represents (1) a cycloalkyl or cycloalkenyl group of 4-7 carbon atoms which is unsubstituted or substituted by at least one alkyl group of 1-4 carbon atoms, (2) an anthryl or naphthyl group, (3) a phenyl group which is unsubstituted or substituted by at least one of (a) halogen atom, (b) trifluoromethyl group, (c) hydroxyl group, (d) nitro group, (e) carboxyl group, (f) amino group which may be substituted by alkyl group(s) of 1-4 carbon atoms, (g) alkyl, alkoxy or alkylthio group of 1-5 carbon atoms, (h) phenyl group, (i) heterocyclic group containing at least one of nitrogen, oxygen and sulfur atoms which is unsubstituted or substituted by at least one of the above-described substituents (a) to (h), and (j) alkyl group of 1-4 carbon atoms which is substituted by at least one of the above-described substituents (c), (h) and (i), (4) a heterocyclic group containing at least one of nitrogen, oxygen and sulfur atoms which is unsubstituted or substituted by at least one of oxo group and the above-described substituents (a) to (h) and (j), or (5) a ##STR2## (wherein R.sup.4 represents a hydrogen atom, a halogen atom, phenyl group or an alkyl group of 1-5 carbon atoms; and R.sup.5 represents a hydrogen atom, a phenyl group or an alkyl group of 1-5 carbon atoms) or ##STR3## or (III) R.sup.1 and R.sup.2, which may be the same or different with each other, each represents a phenyl group which is unsubstituted or substituted by at least one of the above-described substituents (a) to (j); and R.sup.3 represents a hydrogen atom, an alkyl group of 1-12 carbon atoms, an aralkyl group of 7-13 carbon atoms, a cycloalkyl or cycloalkenyl group of 4-7 carbon atoms which is unsubstituted or substituted by at least one alkyl group of 1-4 carbon atoms, or a phenyl group which is unsubstituted or substituted by at least one of the above-described substituents (a) to (j)] and, when R.sup.3 represents a hydrogen atom, non-toxic salts of the acids possess a strong inhibitory activity on aldose reductase, and are useful for the prevention and treatment of nerve disturbances such as neuralgia, retinopathy, diabetic cataract and renal disturbances such as tubular nephropathy.