| abstract |
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], <IMAGE> [I] <IMAGE> [II] wherein R1 is hydroxy which can be protected by a protective group; R2 is lower alkyl; R3 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; R4 is tetrazolyl, phosphonol or lower alkyl ester thereof, or sulfonyl or lower alkyl ester thereof, and A is alkylene. |