| 摘要 |
<p>PCT No. PCT/FR97/00840 Sec. 371 Date Nov. 11, 1998 Sec. 102(e) Date Nov. 11, 1998 PCT Filed May 13, 1997 PCT Pub. No. WO97/43297 PCT Pub. Date Nov. 20, 1997An isomerization method wherein a compound of formula wherein X and y together form a 3-oxo radical, or X is a hydrogen atom and Y is either a radical a where R2 is OH or O-acyl, or an O-alkyl or NH2 radical; R1 is a hydrogen atom or a methyl radical; Z is hydrogen or an acyl radical; and R is a hydrogen atom, an NH2 radical or a (CH2)nAr, NH(CH2)nAr or N=CH(CH2)nAr radical, in the form of a 10 alpha isomer or a mixture of 10 alpha and 10 beta isomers, is exposed to a basic agent to give the corresponding compound of formula I in which the 10-methyl radical is in the beta position.</p> |
