IMPROVED METHOD FOR PREPARING MALEATE SALT OF PARA-SUBSTITUTED CIS-CYCLOHEXYLAMINO NITRILE

Disclosed is an improved method for preparing a maleate salt of cis-para-substituted cyclohexylamino nitrile depicted by formula (I), the method comprising adding maleic acid, at a molar ratio of 0.3 to 0.55, to a solution of para-substituted cis- and trans-cyclohexylamino nitrile compounds corresponding to formula (I) in an organic solvent, performing stirring and ultrasonic treatment, and then performing further processes such as filtering to obtain the maleate salt of cis-para-substituted cyclohexylamino nitrile depicted by formula (I), where R1 is a C1-C10 alkyl or alkyloxy group, a C1-C10 alkenyl or alkenyloxy group, a C1-C10 alkynyl or alkynyloxy group, a C1-C10 cycloalkyl or cycloalkyloxy group, or a C1-C10 heterocycloalkyl or heterocycloalkyloxy group containing 1-2 heteroatoms selected from O and N, and HX is maleic acid.