Compounds of formula I are provided where X
1
, X
2
and X
3
are independently selected from H or hydroxy protecting groups. Such compounds are used in preparing pharmaceutical compositions and are useful in treating a variety of biological conditions.
提供了
化学式为I的化合物,其中X1、X2和X3独立地选择自H或羟基保护基团。这些化合物用于制备制药组合物,并可用于治疗各种
生物状况。