Derivatives of methylene diphosphonic acid, preparation of the same pharmaceutical compositions containing the same

Abstract From the Canadian patent

The present invention relates to new pharmaceutically-active products of the formula (I), in which:, - R1 is hydrogen or a straight or branched lower alkyl group having from 1 to 4 carbon atoms, - R2 is : . hydrogen, . an alkyl group having from 1 to 20 carbon atoms which is unsubstituted or substituted by a hydroxy group a, thiol group, one or more halogen atoms an, alkoxycarbonyl group, a phenyl group or an group where Z1 and Z2, considered independently of one another, are hydrogen or an alkyl group having from 1 to 4 carbon atoms, a phenyl group which is unsubstituted or substituted one or more times by halogen, a nitro group an alkyl, group having from 1 to 4 carbon atoms an alkoxy …