Process for the preparation of 2-bromo-alpha-ergocryptine or of its mesylate

摘要

alpha -Ergocryptine is reacted with 1,3-dibromo-5,5-dimethyl-2,4-imidazolinedione in an inert solvent at a temperature of 0 to 55 DEG C in the presence of 2,2'-azobisisobutyronitrile. The mixture obtained is concentrated under vacuum to dryness and the residue is dissolved in a low molecular weight halogenated solvent and washed with an aqueous inorganic base solution and with water. After drying, treatment with active charcoal and concentrating to a small volume, the product is separated from the mixture by column chromatography by eluting with the same halogenated solvent, ethanol being added until a concentration of 5% by volume is achieved. The product-rich fractions are concentrated to dryness and recrystallised. The product obtained may be converted to its mesylate by acidification with methanesulphonic acid in an inert solvent and then evaporated to crystallisation. The final products are used to inhibit prolactin secretion and to inhibit growth hormone.