METHOD FOR PURIFYING GUANIDINE DERIVATIVE

摘要

PROBLEM TO BE SOLVED: To provide a method for purifying 1-(2-chloro-5-thiacolylmethyl)-3- methyl-2-nitroguanidine or its salt. SOLUTION: This method for purifying a guanidine derivative is to industrially purify 1-(2-chloro-5-thiazolylmethyl)-3-methyl-2-nitroguanidine or its salt in high purity by subjecting an alkali aqueous solution containing 1-(2-chloro-5- thiazolylmethyl)-3-methyl-2-nitroguanidine or its salt, which is obtained by dissolving 1-(2-chloro-5-thiazolylmethyl)-3 methyl-2-nitroguaanidine or its salt obtained by reacting N-(2-chloro-5-thiazolylmethyl)-O-methyl-N'-nitroisourea or its salt with methyl amine or its salt in the presence of water, to a neutralization process (A) and generated precipitates to a filtration process (B).