Merck + Co., Inc.

Carl Bagner

Arthur S Wildman, Jr

Leonard M Weinstock

A process for the whole broth extraction of avermectins wherein the pH of the whole broth is adjusted with mineral acid and then contacted with a solvent extractant so that the avermectic active component is taken up by the solvent. The now avermectin rich extractant is then processed through a solvent concentration step and the avermectin isolated by conventional crystallization. The extractant is then recycled with appropriate make-up to extract a subsequent batch of whole broth.

Process for the whole broth extraction of avermectin

Improved method of preparing 5-(2,4-difluorophenyl)salicylic acid and derivatives which favors formation of the desired end product over other undesired isomers, comprising the steps of

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Paramus, NJ, United States of America

Carl Bagner