GB626027A - Improvements in or relating to the preparation of tertiary organic base salts of penicillin - Google Patents

Abstract

Salts of penicillin are manufactured by treating a solution of penicillin in a suitable organic solvent or mixture of solvents with a salt or salts of a suitable tertiary organic base or bases and a suitable organic acid or acids. Suitable organic solvents or solvent mixtures are those into which penicillin can be extracted readily from acidified aqueous solution, which are relatively inert to penicillin and in which the tertiary base salts of penicillin are relatively insoluble, e.g. amyl acetate (preferred), diethyl ether, methyl isobutyl ketone or butyl acetate. They are preferably used in conjunction with one or more suitable secondary solvents, i.e. organic solvents in which the tertiary base salts of penicillin are relatively insoluble but those of the impurities relatively soluble, e.g. ethanol (preferably as a 2-10 per cent addition to amyl acetate), butanol or acetone. Suitable tertiary organic bases are those of the general formula NR1R2R3, where R1, R2 and R3 are alkyl or alkenyl groups of not more than 4 carbon atoms, or R1 and R2 are part of a heterocyclic ring which, together with any alkyl substituents, contains not more than 8 carbon atoms, e.g. triethylamine, N-ethylpiperidine or N-ethylhexahydropicoline. Suitable organic acids are aliphatic or substituted aliphatic acids having not more than 8 carbon atoms in the straight chain (e.g. formic, acetic, propionic, butyric, isobutyric, cuprylic or cuproic acid), or benzoic acid. The tertiary base salts of penicillin may be converted into metal (e.g. sodium or calcium) salts, e.g. by the process described in Specification 604,563. Examples illustrate the use of certain of the materials specified above.