The invention discloses a method for synthesizing
clindamycin phosphate, which comprises the following steps of: performing ketal protection reaction on
clindamycin hydrochloride alcoholate at the temperature of between 2.0 below zero and 2.0 DEG C under the action of
acetone and
phosphorus oxychloride to form propylidene
clindamycin; and performing esterification,
hydrolysis, adsorption, washing, deabsorption, concentration, coarse
crystallization, decoloration, refining and
drying to obtain the finished product of
clindamycin phosphate. Because a new catalyst 4-dimethylaminopyridine participates in the esterification in the rection
system, the phosphorylating reaction is performed completely, and the conversion rate of raw materials is improved. Meanwhile, due to the secondary
crystallization method, the problems of poor color grade and poor
powder solubility are solved, and the operating conditions are mild and simple. By adopting
triethylamine to replace partial
pyridine, the esterification is pushed forwards; the reaction period is shortened; and importantly,
related impurities in the finished product and the production cost are reduced, and the content is improved.