Method for preparing salts of polyene macrolide esters

摘要

This method is for preparing salts of amphotericin B methyl ester and other polyene macrolide esters. The steps of the process involve methylation by use of cesium carbonate for converting to methyl ester and significantly reducing side products, which are over methylation products. The free base-Schiff base mixture is converted to amphotericin B methyl ester hydrochloride or some other salt form, by using tetrahydrofuran-water to dissolve the mixture for acid treatment to obtain the salt. The aldehyde liberated during salt formation is removed by centrifuging, as to any precipitated aldehyde, and the aldehyde remaining in solution is removed by eluting the solution through a reverse phase adsorbent to obtain amphotericin B methyl ester hydrochloride as a yellow powder.