Crystal form of N-[(2S, 3R)-4-phenyl-3-benzyl-3-formylaminobenzoxy-2-hydroxybutyryl]-L-benzyl leucine and preparation method thereof

The invention provides a crystal form of an ubenimex intermediate N-[(2S, 3R)-4-phenyl-3-benzyl-3-formylaminobenzoxy-2-hydroxybutyryl]-L-benzyl leucine. The ubenimex intermediate with the crystal form has high purity and good stability and is suitable for further preparing high-purity ubenimex active pharmaceutical ingredients. The invention also provides a preparation method of the crystal form, wherein according to the method, recrystallization is used for preparation; through HPLC (High Performance Liquid Chromatography), the purity of the obtained crystal is over 98.5%; and moreover, the adopted organic solvent is a common solvent with low price, a single-solvent recrystallization is more convenient for recovery, and the method is suitable for industrial production.