IMPROVMENTS IN OR RELATING TO PENICILLINS

摘要

alpha -Aminoacylpenicillin antibiotics such as ampicillin and amoxycillin may be prepared in particularly simple manner by a process which comprises preparing a solution of 6-aminopenicillanic acid (6-APA) in a water-immiscible organic solvent by treating 6-APA with an excess of a strong tertiary amine base in the presence of said solvent; neutralising the residual strong tertiary amine base in said solution; reacting the neutralised solution with a solution in a water-immiscible organic solvent of an acylating agent which is a mixed anhydride of a lower alkoxyformic acid and an N-protected derivative of an alpha -aminoacid wherein the N-protecting group is acid-labile, to yield a solution of an N-protected alpha -aminoacylpenicillin derivative; contacting the resulting solution with water and a strong acid to cleave the acid-labile N-protecting group; and isolating the thus-obtained alpha -aminoacylpenicillin from the resulting water-containing system. The use of water-immiscible solvents in the process obviates the need for a solvent evaporation stage during isolation of the alpha -aminoacylpenicillin product and thus renders the process of particular advantage in plant-scale operations.