| 摘要 |
<p>1461663 Preparing 17-esters of 17α,21-dihydroxy steroids LARK SpA 12 Nov 1974 [4 Jan 1974 (2)] 27543/74 Heading C2U A 17 - monoester of a 17α,21 - dihydroxy steroid is prepared by esterifying the corresponding 17α,21-dihydroxy steroid 21-phosphate with a carboxylic acid, a carboxylic acid anhydride or a carboxylic acid chloride under mild conditions, then dephosphorylating the intermediate 17-acyloxy-21-phosphate by enzymatic hydrolysis using an acid phosphatase at a controlled pH. The acylating agent preferably contains up to 11 C atoms and may be mixed with a diluent. An aqueous suspension, dispersion or solution of cells or tissues or their fragments or constituents, particularly of rice bran, is preferably used for the dephosphorylation carried out in an acidic medium, particularly pH 4-5, and at 10-50‹ C. The enzymatic dephosphorylation may be carried out on the esterification reaction mixture without isolating the 17 - acyloxy - 21 - phosphate. The 17- monoesters obtained may be further esterified to 17,21-diacyl-esters with the acyl residues being the same or different. Forty-one compounds falling within the formula are novel, where R 1 is H, F, Cl, CH 3 or CF 3 ; R 2 is H, OH, CH 3 , methylene or halomethylene; R 3 is H, CF, F, OH, or keto; R 4 is H, F, Cl, Br, CH 3 or methylene; X is H, F, or Cl and R ester groups include formate, acetate, propionate, butyrate, isobutyrate, valerate, isovalerate, caproate, caprylate, palargonate, aenanthate, and benzoate.</p> |
