Patent ID: 6613889
Filing Date: 2003-09-02
Classification: C07H

Abstract:
A process for preparing esters of polyene macrolides comprising:(a) Reacting a mixture containing an amphoteric polyene macrolide antifungal selected from the group consisting of amphotericin B, nystatin, pimaricin, amphotericin A, rimocidin, partricin, and derivatives of said antifungals and anhydrous dimethylformamide with an aldehyde followed by the addition of cesium carbonate and methyl iodide, thereafter precipitating with tertiary-butylmethyl ether, and then stirring in water to produce a free base-Schiff base mixture of the methyl ester; (b) Converting the free base-Schiff base mixture in a single phase liquid reaction, to a salt form by using tetrahydrofuran and water to dissolve the free base-Schiff base mixture, thereafter neutralizing to obtain the salt form; (c) Removing the tetrahydrofuran by azeotroping, and recovering the water soluble salt of the polyene methyl ester in the water; and (d) Removing aldehyde liberated during salt formation by centrifuging and eluting the solution through the reverse phase adsorbent to remove residual aldehyde, and then freeze drying to produce the product.