GB739096A - Tribromosteroids - Google Patents

Abstract

The invention comprises 3-acyloxy-5,6-21-tribromopregnane-20-one where the acyl radical is derived from an organic carboxylic acid preferably containing from 1 to 8 carbon atoms, and the preparation thereof by reacting a 3,20-diacyloxy-5,20-pregnadiene with about two molar equivalents of bromine in an inert organic solvent at a temperature of about minus 40 DEG to about 40 DEG C. Suitable inert solvents are methylene chloride, chloroform and methylchloroform. The reactant for the above process may be obtained by reacting a 3-hydroxy- or 3 - acyloxy - 5 - pregnene - 20 - one with an isopropenyl acylate, e.g. isopropenyl acetate, in the presence of an acidic catalyst, e.g. p-toluenesulphonic acid, sulphosalicyclic acid or sulphoacetic acid. The acyloxy groups in the products and reactants in the above process may be derived from formic, acetic, propionic, butyric, valeric, hexanoic, heptanoic, octanoic, phenylacetic, toluic, benzoic, cyclopentylcarboxylic, cyclohexylcarboxylic and b -cyclopentylpropionic acids. In the example 3b - acetoxy - 5,6, 21 - tribromopregnane-20-one is prepared. The following compounds are also obtainable: 3a -acetoxy-, 3b -propionyl-oxy- and 3a -propionyloxy-5,6,21-tribromopregnane-20-one. 3a , 20- and 3b , 20-diacyloxy-5,20-pregnadienes are obtainable by reacting 3a -hydroxy- or 3b -hydroxy-5-pregnene-20-one with an acylating agent such as a ketene, an acid, an acid anhydride or an acid chloride, in an organic solvent such as pyridine, benzene or toluene, and reacting the thus produced 3a - or 3b -acyloxy-5-pregnene-20-one with an isopropenyl acylate such as isopropenyl acetate in the presence of an acidic catalyst, e.g. p-toluene-sulphonic acid, sulphoacetic acid or sulphosalicyclic acid. Alternatively, the compounds may be prepared by the direct acylation of 3a - or 3b -hydroxy-5-pregnene-20-one with an isopropenyl acylate as referred to above. 3 - Acetoxy - 21 - iodo - 5 - pregnene - 20 - one is prepared by treating 3-acetoxy-5,6,21-tri-bromo-pregnane-20-one with potassium iodide and ethyl alcohol.