@ A process for the preparation of 16,17 acetals of pregnane derivatives by trans-ketalization of 16,17-acetonides is described.
In the instance of the preparation of 16a,17a-butylide- nedioxy-11β,21-dihydroxypregna-1,4-diene-3,20-dione, a compound having useful therapeutic properties, known also as budesonide, it is possible to obtain the more active epimer with high selectivity and remarkable economic advantages in comparison with the known methods.
New 16,17 acetals of pregnane derivatives, which can be prepared by the method of the invention, are also described.
本发明描述了一种通过 16,17-
丙酮的反酮化作用制备孕烷衍
生物的 16,17-
乙缩醛的工艺。 在制备 16a,17a-丁基-奈迪奥酮-11β,21-二羟基孕甾-1,4-二烯-3,20-二酮(一种具有实用治疗特性的化合物,也称为
布地奈德)的实例中,可以获得活性更高的外嵌体,与已知方法相比,具有高选择性和显著的经济优势。 本发明还描述了可通过本发明方法制备的新的孕烷衍
生物 16,17-
乙缩醛。