3,11-diketo-17,20-dihydroxypregnanes and process

Claim 1

THE PROCESS OF PREPARING 3,11-DIKETO-17,20DIHYDROXY PREGNANE IN SUBSTANTIALLY PURE FORM, WHICH COMPRISES REACTING A MIXTURE CONTAINING $**17,20-3,11-DIKETO-PREGNANE AND $**20,21-3,11-DIKETOPREGNANE WITH A COMPOUND SELECTED FROM THE CLASS WHICH CONSISTS OF OSMIUM TETROXIDE AND HYDROGEN PEROXIDE TO PRODUCE A MIXTURE CONTAINING 3,11-DIKETO-17,20-DIHYDROXY PREGNANE, 3,11DIKETO- 20 - ALPHA - 21 DITHYDROXY PREGNANE, AND 3,11-DIKETO-20-BETA-21-HYDROXY-PREGNANE; REACTING THIS MIXTURE WITH A CYCLIC ANHYDRIDE OF A DICARBOXYLIC ACID TO CONVERT THE 20,21-DIHYDROXY CARBOXYLIC ACID TO CONVERT THE 20,21-DIHYDROXY STEREOISOMERS TO THE CORRESPONDING STEROISOMERS OF 3,11-DIKETO-20-HYDROXY-21-(CARBOXY-ACYLOXY) PREGNANE ADMIXED WITH UNCHANGED 3,11-DIKETO17,20-DIHYDROXY-PREGNANE; SEPARATING THE NONACIDIC 3,11-DIKETO-17,20-DIHYDROXY PREGNANE FROM THIS MIXTURE; REACTING THIS COMPOUND WITH AN ACYLATING AGENT TO PRODUCE 3,11-DIKETO-17-HYDROXY-20-ACYLOXY-PREGNANE; PURIFYING THIS ACYLOXY DERIVATIVE BY FRACTIONAL CRYSTALLIZATION; AND HYDROLYZING TO PRODUCE THE DESIRED 3,11-DIKETO17,20-DIHYDROXY PREGNANE IN SUBSTANTIALLY PURE FORM.