| 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 hydroxy protective group; R<2> is lower alkyl; R<3> is hydrogen, lower alkyl, hydroxy, which can be protected by a hydroxy protective group, or lower alkoxy, and the said lower alkyl can be substituted by hydroxy, which can be protected by a hydroxy protective group, amino or lower alkylamino; R<4> is carboxy which can be converted into ester or amide; tetrazolyl; phosphono which can be converted into ester or amide; or sulfonyl which can be converted into ester or amide; A is alkylene; B is C=O, C=S or CH2, and @ is single bond or double bond.h |
