| 摘要 |
<p>PURPOSE:To easily synthesize a coprostanediol derivative useful as a synthetic intermediate for a vitamin D derivative in large amount and high yield by a specific method using inexpensive lithocholic acid as a starting raw material. CONSTITUTION:This coprostanediol derivative of formula IV (R6 and R7 each is a lower alkyl) is produced by reducing a compound of formula I (R1 is H or a protecting group; R2 is a lower alkyl) with sodium borohydride preferably using methanol, etc., as an activating agent, converting the product into a compound of formula II (R3 is an eliminable group) preferably in the presence of triphenyl phosphine, imidazole and iodine by iodination reaction, etc., reacting the compound with a metal cyanide (preferably sodium cyanide), reacting the reaction product with an alcohol under acidic condition and reacting the resultant compound of formula III (R4 is a lower alkyl) with an organometallic reagent (preferably methylcerium dichloride).</p> |
