Patent ID: 9464095
Filing Date: 2016-10-11
CPC Classification: C07D

Claim Text:
1. A production method of a compound (A) having high purity, comprising: a process (a); and a process (b): (a) a process of mixing a mixture containing a compound (A): where R 1 and R 2 are methyl groups; R 3 is a hydrogen atom, a C 1-6 alkyl group, or a C 1-6 acyloxy group; and X is a hydrogen atom, a halogen atom, or a C 1-6 alkyl group, and as an impurity, a compound (B): where R 1 , R 2 , R 3 , and X are the same as defined above, with a solvent and a metal salt, and (b) a process of obtaining a mixture in a solution state in which the content of the compound (B) has decreased compared to that in the mixture in the process (a) by filtering a mixed solution obtained in the process (a), or a process of obtaining a mixture in which the content of the compound (B) has decreased compared to that in the mixture in the process (a) by further evaporating the solvent or crystallizing following the filtering; wherein the solvent is an alcohol, a halogen-containing hydrocarbon, a ketone, an ester, an aromatic hydrocarbon, an aliphatic hydrocarbon, or an ether; and the metal salt is a copper salt, a cobalt salt, a manganese salt, a titanium salt, a magnesium salt, an iron salt, a lithium salt, an aluminum salt, a cesium salt, or a silver salt.