| 摘要 |
Compounds of the formula WHEREIN R1 represents a lower alkyl radical, a cycloalkyl radical, or a phenyl radical optionally substituted by chlorine and/or bromine, OF THE SYMBOLS R2 and R3 any one represents hydrogen, a lower alkyl radical, a cycloalkyl radical, a phenyl radical optionally substituted by chlorine, and the other then represents the radical: |
