The present invention provides a method for purifying (2R,3R,4S)-6-amino-4-[N-(4-chlorophenyl)-N-(1H-imidazol-2-ylmethyl)amino]-3-hydroxy-2-methyl-2-dimethoxymethyl-3,4-dihydro-2H-1-benzopyran, comprising converting amorphous (2R,3R,4S)-6-amino-4-[N-(4-chlorophenyl)-N-(1H-imidazol-2-ylmethyl)amino]-3-hydroxy-2-methyl-2-dimethoxymethyl-3,4-dihydro-2H-1-benzopyran into a crystal form thereof. In addition, the present invention provides: a novel crystal form of the (2R,3R,4S)-6-amino-4-[N-(4-chlorophenyl)-N-(1H-imidazol-2-ylmethyl)amino]-3-hydroxy-2-methyl-2-dimethoxymethyl-3,4-dihydro-2H-1-benzopyran； and a preparation method therefor.La présente invention concerne un procédé de purification de(2R,3R,4S)-6-amino-4-[N-(4-chlorophényl)-N-(1H-imidazol-2-ylméthyl)-amino]-3-hydroxy-2-méthyl-2-diméthoxyméthyl-3,4-dihydro-2H-1-benzopyrane, comprenant la conversion de (2R,3R,4S)-6-amino-4-[N-(4-chlorophényl)-N-(1H-imidazol-2-ylméthyl)-amino]-3-hydroxy-2-méthyl-2-diméthoxyméthyl-3,4-dihydro-2H-1-benzopyrane amorphe en une forme cristalline. De plus, la présente invention concerne : une nouvelle forme cristalline du (2R,3R,4S)-6-amino-4-[N-(4-chlorophényl)-N-(1H-imidazol-2-ylméthyl)-amino]-3-hydroxy-2-méthyl-2-diméthoxyméthyl-3,4-dihydro -2H-1-benzopyrane ； et un procédé de préparation correspondant.본 발명은 무정형의 (2R,3R,4S)-6-아미노-4-[N-(4-클로로페닐)-N-(1H-이미다졸-2-일메틸)아미노]-3-하이드록시-2-메틸-2-다이메톡시메틸-3,4-다이하이드로-2H-1-벤조피란을 이의 결정형으로 전환하는 것을 포함하는 (2R,3R,4S)-6-아미노-4-[N-(4-클로로페닐)-N-(1H-이미다졸-2-일메틸)아미노]-3-하이드록시-2-메틸-2-다이메톡시메틸-3,4-다이하이드로-2H-1-벤조피란의 정제방법을 제공한다. 또한, 본 발명은 상기 (2R,3R,4S)-6-아미노-4-[N-(4-클로로페닐)-N-(1H-이미다졸-2-일메틸)아미노]-3-하이드록시-2-메틸-2-다이메톡시메틸-3,4-다이하이드로-2H-1-벤조피란의 신규 결정형 및 이의 제조방법을 제공한다.
