Enzymatic bromination of 16-dehydroestradiol 3-methyl ether 17-acetate to 16-alpha-bromoestrone 3-methyl ether.

A recent communication from these laboratories (S. L. Neidleman et al., Tetrahedron Letters 44:5337, 1966) described the bromination and chlorination of the steroidal f3-diketones, 16ketoprogesterone and 16-keto-A-norprogesterone, and the bromination of the steroidal j-ketolactone, 15-keto-1-dehydrotestololactone, by the chloroperoxidase of Caldariomycesfumago (F. S. Brown and L. P. Hager, J. Am. Chem. Soc. 89:719, 1967). In a later publication, we detailed the bromination of the a-hydroxymethylene ketosteroids, 2-hydroxymethylene-17,B-hydroxy5a-androstan-3-one and 2-hydroxymethylene17f3-hydroxy-5f3-androstan-3-one, by the same of distilled water, 120 ml of 0.3 M potassium phosphate buffer (pH 3.0), 300 mg of 16-dehydroestradiol 3-methyl ether 17-acetate in 24 ml of dimethylsulfoxide, and 36 ml of distilled water. The mixture was distributed in 200-ml samples among three 500-ml Erlenmeyer flasks, which were placed on a rotary shaker (280 cycles per min, 2-inch stroke) at 25 C for 30 min. The reaction mixtures were pooled and extracted with 150 ml of chloroform. The chloroform extract was dried with anhydrous sodium sulfate and was concentrated at reduced pressure (1,000 ,) and room temperature (25 C). The concentrate was streaked on an 8 by 16 inch (20.3 by 41 cm) plate