| 摘要 |
A process for the dehydrobromination of an a -bromo-ketone having a hydrogen atom attached to a carbon atom positioned beta to the keto group comprises treating the a -bromo-ketone with an alkaline earth metal (including magnesium) oxide or hydroxide or a mixture thereof, in an N,N-dialkyl amide of a carboxylic acid or an N-alkyl-2-pyrrolidone as solvent. A lithium halide may be used in conjunction with the alkaline earth metal oxide, hydroxide or mixture thereof. The invention is particularly described with reference to the dehydrobromination of a -bromo-keto steroids of the cholestane, spirostane, androstane, estrane and pregnane series and also of 2a -methyl-2,4-dibromo - 4,5 - dihydro - allo - testololactone and 1,3 - dibromo - 2 - keto - A - nor - spirostane, to yield the corresponding a ,b -unsaturated keto steroids. The following conversions are also described. 16 - Methyl - 5,16 - pregnadien - 3b - ol - 20 - one -->16b - methyl - 5 - pregnen - 3b - ol - 20 - one -->16b - methyl - progesterone. 16 - Methyl-5,16 - pregnadiene - 3b - ol - 20 - one-->16b -methyl - 16a ,17a - oxido - 5 - pregnen - 3b - ol-20 - one-->16 - methylene - 17a - hydroxy-pregnenolone. 16b - Methyl - 1,4 - pregnadiene-17a ,21 - diol - 3,20 - dione 21 - acetate-->16b -methyl - 1,4 - pregnadiene - 11a ,17a ,21 - triol-3,20-dione using a microorganism of the genus Glomerella (e.g. G. Cingulata). |
