| 摘要 |
This invention relates to the compounds of the formula [I] which are useful for the treatment of cataracts, and the synthetic intermediates of the formula [II], <CHEM> wherein R<1> is hydroxy which can be protected by a protective group; R<2> is lower alkyl; R<3> is hydrogen, lower alkyl, hydroxy, which can be protected by a protective group, or lower alkoxy, and the said lower alkyl can be substituted by hydroxy, which can be protected by a protective group, amino or lower alkylamino; R<4> is tetrazolyl, phosphonyl or lower alkyl ester thereof, or sulfonyl or lower alkyl ester thereof, and A is alkylene. |
