| 摘要 |
<p>Disclosed is a method for preparing a pregnane derivative 16,17-acetal (ketal) compound shown in the general formula I, the method comprising the step of reacting a compound of a general formula II with a compound of a general formula III or a general formula IV in the presence of boron trifluoride, wherein the dotted line between site 1 and site 2 denotes a saturated or unsaturated bond; R is hydroxyl, halogen or -OCOR7, wherein R7 is a C1-C12 linear chain or branched alkyl, a C3-C10 cycloalkyl, a C2-C8 alkenyl or a C2-C8 alkynyl; R1 and R2 are each hydrogen, a C1-C12 linear chain or branched alkyl, a C3-C10 cycloalkyl, a C2-C8 alkenyl or a C2-C8 alkynyl, or R1, R2 and the carbon to which they are connected form a C3-C10 cycloalkyl together, with the provision that R1 and R2 are not hydrogen simultaneously; R3 is hydrogen or -OCOR8, wherein R8 is a C1-C12 linear chain or branched alkyl, or a C3-C10 cycloalkyl; R4 is hydrogen, fluorine or chlorine; R5 is hydrogen, fluorine, chlorine or methyl; and R6 is a C1-C12 linear chain or branched alkyl. Compared with current processes, the method causes little pollution to the environment, has relatively mild reaction conditions, ease of control, reduced energy consumption and low production costs.</p> |
