A compound of formula (I)
wherein
n is 0 to 4;
R is ethyl or vinyl;
R1 is hydrogen or (C1-6)alkyl,
R2 is hydrogen or
- cycloalkyl including (C3-6)cycloalkyl, or
- unsubstituted (C1-6)alkyl, or
- (C1-6)alkyl substituted by one or more of
- hydroxy; preferably one or two,
- halogen,
- (C3-6)cycloalkyl, or
R1 is hydroxy and R2 is formyl.
化合物的式子为(I),其中n为0至4;R为乙基或
乙烯基;R1为氢或(C1-6)烷基;R2为氢或环烷基,包括(C3-6)环烷基,或未取代的(C1-6)烷基,或被一个或多个取代的(C1-6)烷基,其中取代基为-羟基,优选为一个或两个,-卤素,-(C3-6)环烷基,或R1为羟基且R2为甲酰基。