Method for synthesizing methylaminoabamectin benzoate

The invention provides an abamectin derivative which has sulfonyl group in the C4 position of abamectin. The invention also provides a preparation method of the abamectin and a preparation method of an ammonified abamectin derivative. The invention also provides a synthesis method of emamectin benzoate. The technical scheme can simplify the production technique, lower the production cost and reduce the byproduct discharge. In the five-step reaction process of single protection, sulfonation, ammonification, deprotection and benzoic acid salification by using abamectin as the initial raw material, the same solvent can used, and no replacement of solvent is needed, thereby enhancing the product production efficiency and lowering the production cost. Besides, the method can avoid using the step of oxidizing C4'-hydroxyl into C4'-carbonyl, thereby avoiding the conditions of effluvium and catalyst B poisoning generated by sulfur-containing impurities, effectively lowering the discharge of wastewater and waste gas, and lowering the consumption of the catalyst B.