摘要 |
This invention relates to a selective acylation process for the preparation of phenolic N-disubstituted carbamate esters of steroids, comprising reacting in an inert solvent an acylating agent being a carbamoyl halogenide, a 4-(tertiary amino)-pyridine, or a complex thereof, optionally as a part of a polymer and a steroid having at least two free hydroxy groups, where at least one is phenolic and at least one is alcoholic, optionally in the presence of an acid acceptor. |