| 摘要 |
<p>A process for the preparation of new stable homogeneous hydrogenation catalysts, comprising the reaction of a rhodium salt or complex with a hydrazine, or a salt thereof, eventually in the presence of excess tertiary phosphine, and their application in very reduced quantities in improved processes for the stereoselective hydrogenation of 6-deoxy-6-demethyl-6-methylenetetracyclines and for the simultaneous dehalogenation and stereoselective hydrogenation of 11a-chloro-6-deoxy-6-demethyl-6-methylenetetracyclines, to furnish alpha -6-deoxy-tetracyclines in high yields and purities. </p> |
