Alkanediphosphonic acids, in particular heteroarylalkanediphosphonic acids of formula ##STR1## wherein R.sub.1 is a 5-membered heteroaryl radical which may be fused with benzene or cyclohexene nuclei and which contains, as hetero atoms, 2 to 4 N-atoms or 1 or 2 N-atoms as well as 1 O- or S-atom, and which is unsubstituted or C-substituted by lower alkyl, phenyl or phenyl which is substituted by lower alkyl, lower alkoxy and/or halogen, or by lower alkoxy, hydroxy, di-lower alkylamino, lower alkylthio and/or halogen, and/or is N-substituted at a N-atom which is capable of substitution by lower alkyl, lower alkoxy and/or halogen, and R.sub.2 is hydrogen, hydroxy, amino, lower alkylthio or halogen, and salts thereof, have regulatory action on calcium metabolism and can be used as medicaments for the treatment of diseases associated with impairment of calcium metabolism. The compounds are obtained for example by converting, in a compound of formula ##STR2## wherein X.sub.1 is a functionally modified phosphono group and X.sub.2 is a free or functionally modified phosphono group, X.sub.1 and, if appropriate X.sub.2, into the free phosphono group.
烷基
二膦酸,特别是公式##STR1##中的杂环烷基
二膦酸,其中R.sub.1是一个五元杂环基团,可以与苯或
环己烯核融合,并且包含作为杂原子的2至4个N原子或1或2个N原子以及1个O或S原子,其未被取代或被低碳基,苯基或被低碳基,低烷氧基和/或卤素取代的苯基取代,或被低烷氧基,羟基,二低烷基
氨基,低烷基
硫基和/或卤素取代,和/或在可被低碳基,低烷氧基和/或卤素取代的N原子处被N取代,R.sub.2是氢,羟基,
氨基,低烷基
硫基或卤素,以及其盐,对
钙代谢具有调节作用,可用作治疗与
钙代谢障碍相关疾病的药物。例如,通过将公式##STR2##化合物中的X.sub.1为功能修饰的
膦酸基团,将X.sub.1和如适当的X.sub.2转化为自由
膦酸基团来获得化合物。