| abstract |
(57) [Summary] [Object] To provide novel phosphonic acids, a method for preparing them and a pharmaceutical composition containing them. [Structure] The following general formula (I): In the formula, R 1 is a hydroxyl group, alkoxy, or a (substituted or unsubstituted group) amino group, R 2 is an unsubstituted or substituted alkyl group, X 1 is -NH-, X 2 is -O-, R 3 is a hydrogen atom or an alkyl or phenyl group, R 4 is a hydroxyl group, benzyloxy, benzyloxycarbonylamino, amino, mono- or dialkylamino, acetoxy, or 2,2. An alkyl group substituted by one or more groups of dimethyl-1,3-dioxolan-4-yl group, wherein the substituents are the same or different, R 5 is 3-indolylmethyl, naphthylmethyl, alkyl, A compound represented by a phenyl or benzyl group, an isomer thereof, and an addition salt with a pharmaceutically acceptable acid or base. |