Process for producing erythromycin derivative

摘要

The present invention relates to a method for preparing a crystal of a fumarate salt of a compound represented by Formula (II):
(wherein R 1 represents a hydrogen atom or a lower alkyl group, and R 2 represents a lower alkyl group), which comprises crystallizing a fumarate salt of the compound represented by Formula (II) from isopropanol. Furthermore, the present invention relates to a method for preparing a crystal of a fumarate salt of a compound represented by Formula (II) (wherein R 1 represents a hydrogen atom or a lower alkyl group, and R 2 represents a lower alkyl group), which comprises recrystallizing a crystal of a fumarate salt of the compound represented by Formula (II) from isopropanol.