The application is directed to a process for increasing the proportion of 7β-epimer in an 7α/7β-epimer mixture of a 7-substituted 6α,14α-ethenomorphinan or a 7-substituted 6α,14α-ethanomorphinan, and specifically of compounds of Formula (I), wherein G, R
2
-R
4
, and are defined as set forth in the specification. The application is also directed to a process for purifying the 7β-epimer from an 7α/7β-epimer mixture of a 7-substituted 6α,14α-ethenomorphinan or a 7-substituted 6α,14α-ethanomorphinan. The application is also directed to a process for preparing 7β-substituted compounds of Formula V
b
wherein G and R
2
-R
5
are defined as set forth in the specification.
本申请涉及一种用于增加7-取代-6α,14α-
乙烯吗啡烷或7-取代-6α,14α-
乙烷吗啡烷的7α/7β-表异构体混合物中7β-表异构体比例的方法,具体地,涉及公式(I)中G,R2-R4的化合物。本申请还涉及一种从7-取代-6α,14α-
乙烯吗啡烷或7-取代-6α,14α-
乙烷吗啡烷的7α/7β-表异构体混合物中纯化7β-表异构体的方法。本申请还涉及一种制备公式Vb中G和R2-R5所定义的7β-取代化合物的方法。