Compounds of the formula (I)
A is OH or a carbonyl group,
n is 0 or 1,
R is an alkyl radical having from 1 to 4 carbon atoms, in particular methyl, ethyl, n-propyl, iso-propyl, n-butyl or t-butyl; or a residue of a hydroxy carboxylic acid, in particular the residue —CH(OH)COOH, —CH(OH)CH
2
COOH, —CH
2
CH(OH)COOH or —CH(OH)CH(OH)COOH; and
R′ is independently selected from H or OH.
化合物的公式(I)中,A为OH或羰基,n为0或1,R为具有1至4个碳原子的烷基基团,特别是甲基、乙基、正丙基、异丙基、正丁基或叔丁基;或羟基
羧酸的残基,特别是残基—CH(OH)COOH,—CH(OH)CH2COOH,—CH2CH(OH)COOH或—CH(OH)CH(OH)COOH;而R′独立地从H或OH中选择。