either NCS or- NBS in ether at 25° followed by mild acidic hydrolysis has led to the corresponding 21-haloketones in high yield. Application of this halogenation procedure to 2-pentanone demonstrated that this method may be general for the selective halogenation of the Me group of methylketones.
用
NCS或-
NBS在
乙醚中于25°处理
乙醇胺衍生的2个甾体20-酮的酮
亚胺,然后进行温和的酸性
水解,从而以高收率得到了相应的21-卤代酮。该卤化方法在
2-戊酮上的应用证明,该方法对于甲基卤代Me的Me基团的选择性卤化可能是通用的。