| 摘要 |
<p>A process for preparing a compound of formula (I), wherein R1 and R2 each are hydrogen; A is CH2, CHOH or C=O; R is hydrogen or C1-4alkyl, C1-4alkoxy, hydroxy or halogen. Also disclosed is a compound of formula (I), wherein R1 and R2 each are hydroxy-protecting group; or R1 and R2 may be joined together to form -(CH2)n-; n is 1 to 3; A is CHOR1 or C=O; R is hydrogen or C1-4alkyl; and R4, R5 and R6 each are independently hydrogen, C1-4alkyl, C1- 4alkoxy, hydroxy or halogen.</p> |
