Patent EP-0045165-A1 (EP)
Inventor: TADAO TANOUCHI
IPC: A61P3/08
Filed: 1981-07-20
Abstract: Rhodanine derivatives, process for their preparation, and aldose reductase inhibitor containing such derivatives. A rhodanine derivative of the general formula:
     is disclosed wherein R' represents a hydrogen atom, an alkyl group of 1-12 carbon atoms, an aralkyl group of 7-13 carbon atoms, a cycloalkyl 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 halogen atom, trifluoromethyl group, phenyl group, nitro group, hydroxyl group, carboxyl group, amino group which may be substituted by an alkyl group of 1-4 carbon atoms, or alkyl, alkoxy or alkylthio group of 1-4 carbon atoms; R 2  and R 3 , which may be the same or different, each represents a hydrogen atom, an alkyl group of 1-4 carbon atoms, or a phenyl group which is unsubstituted or substituted by at least one halogen atom, trifluoromethyl group, phenyl group, nitro group, hydroxyl group, carboxyl group, amino group which may be substituted by an alkyl group of 1-4 carbon atoms, or alkyl, alkoxy or alkylthio group of 1-4 carbon atoms; R 4  represents an alkyl group of 1-4 carbon atoms, a cycloalkyl group of 4-7 carbon atoms which is unsubstituted or substituted by at least one alkyl group of 1-4 carbon atoms, a phenyl or benzyl group which is unsubstituted or substituted by at least one halogen atom, trifluoromethyl group, phenyl group, nitro group, hydroxyl group, carboxyl group, amino group which may be substituted by an alkyl group of 1-4 carbon atoms, or alkyl, alkoxy or alkylthio group of 1-4 carbon atoms, a naphthyl group, an anthracenyl group, or a heterocyclic group containing at least one of nitrogen, oxygen and sulfur atoms which is unsubstituted or substituted by at least one halogen atom, trifluoromethyl group, phenyl group, nitro group, hydroxyl group, carboxyl group, amino group which may be substituted by an alkyl group of 1-4 carbon atoms; or alkyl, alkoxy or alkylthio group of 1-4 carbon atoms; R 5  represents a hydrogen atom, an alkyl group of 1-4 carbon atoms, a cycloalkyl group of 4-7 carbon atoms which is unsubstituted or substituted by at least one alkyl group of 1-4 carbon atoms, a phenyl or benzyl group which is unsubstituted or substituted by at least one halogen atom, trifluoromethyl group, phenyl group, nitro group, hydroxyl group, carboxyl group, amino group which may be substituted by an alkyl group of 1-4 carbon atoms, or alkyl, alkoxy or alkylthio group of 1-4 carbon atoms, a naphthyl group, an anthracenyl group, or a heterocyclic group containing at least one of nitrogen, oxygen and sulfur atoms which is unsubstituted or substituted by at least one halogen atom, trifluoromethyl group, phenyl group, nitro group, hydroxyl group, carboxyl group, amino group which may be substituted by an alkyl group of 1-4 carbon atoms, or alkyl, alkoxy or alkylthio group of 1-4 carbon atoms, with the proviso that when R 5  represents a hydrogen atom, R 4  does not represent an alkyl group of 1-4 carbon atoms; n is 0, 1 or 2; or when R' represents a hydrogen atom, a non-toxic salt of the acid. 
     The derivatives of formula I and their non-toxic acid salts 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.