GB651832A - Process for preparing dihydrostreptomycin and acid salts thereof - Google Patents

Abstract

Dihydrostreptomycin and its salts are manufactured by treating a salt of streptomycin with hydrogen in the presence of a hydrogenation catalyst, and, if desired, treating the resulting dihydrostreptomycin salt with the stoichiometric equivalent of a base which forms with the acid component of the salt an insoluble compound, which is removed by filtration and free dihydrostreptomycin recovered from the filtrate (e.g. by precipitation with an organic solvent or by freeze-drying, the latter being applicable to the recovery of the dihydrostreptomycin salt after removal of the catalyst by filtration). The products retain the antibiotic properties of the parent materials but possess greater stability. The starting materials may be impure concentrates of streptomycin salts, but it is preferable to use a substantially pure salt, the acid component being one which either resists reduction, or, if reduced, does not react with or prevent reduction of streptomycin, e.g. mineral acid salts or salts of organic acids which contain no reducible p group other than C=C bonds. In examples: (1) and (2) an aqueous suspension of platinum oxide is reduced with hydrogen, after which streptomycin hydrochloride is added and the mixture is agitated in an atmosphere of hydrogen to produce dihydrostreptomysin hydrochloride, which may be converted to the helianthate by the action of methyl orange in aqueous methanol; (3) streptomycin sulphate is hydrogenated as in (1) (except that the platinum oxide is not pre-reduced); (4) the platinum oxide in (1) is replaced by palladium metal; (5) an aqueous solution of dihydrostreptomycin sulphate is treated with barium hydroxide solution, the product is filtered, and dihydrostreptomycin is precipitated from the filtrate by adding acetones.