DIPHOSPHONIC ACID DERIVATIVES, PROCESSES FOR THE PREPARATIONTHEREOF AND PHARMACEUTICAL COMPOSITION CONTAINING THEM

Alkyldiphosphonic acid derivatives of the general formula: (I) wherein Het is a heteroaromatic five-membered ring containing 2 to 3 heteroatoms which can be partly hydrogenated and optionally substituted one or more times by alkyl, alkoxy, phenyl cyclohexyl, cyclohexylmethyl, halogen or amino, whereby two adjacent alkyl substituents can together also form a ring, X is a hydrogen atom, a hydroxyl group or an amino group optionally substituted by lower alkyl and R is a hydrogen atom or a lower alkyl radical, with the proviso that Het is not a pyrazole ring; as well as the pharmacologically acceptable salts thereof, are useful in the treatment of calcium metabolism disturbances, for example, treatment of osteoporosis; processes for the preparation of the compounds and pharmaceutical compositions containing them are also described.