| 摘要 |
Prepn. of stable homogeneous hydrogenation catalysts comprises reaction of a Rh salt or complex with R'1R'2N.NR'3R'4 (R'1=Ph or benzenesulfonyl, R'2,R'3,R'4=H). The catalysts are useful for the stereospecific hydrogenation of the 6-CH2 gp. in 6-deoxy-6demethyl-6- methylene-5-hydroxytetracycline (I) or its 11a-halo derivs. to give doxycycline in high yield and purity. Since only a small amt. of catalyst is required compared with the prior catalyst, the process is more economic to perform. |
