| 主权项 |
1. A process for preparing alanylglutamine, comprises the following steps:
step 1) reacting N-(α-chloro)-propionyl-glutamine with hydrazine compound that is selected from the group consisting of hydrazine, methyl hydrazine, ethyl hydrazine and hydrazine hydrate at atmospheric pressure to yield an alanylglutamine crude product; step 2) mixing anhydrous methanol and the alanylglutamine crude product at the temperature between 0° C. and room temperature, then filtering to remove methanol solution, which yields a filter cake containing alanylglutamine; step 3) dissolving the filter cake with water, heating the resulting aqueous solution up to 80° C., and keeping at that temperature for a period of time to concentrate, then adding one to three fold of ethanol to the aqueous solution by volume, and cooling gradually to yield a pure alanylglutamine by recrystallization; wherein, the cooling process in the step 3) consists of three cooling intervals: in the first cooling interval, the temperature cooling from the system temperature to 55° C. by a rate of 1-3° C./hour after concentrating and addition of ethanol; in the second cooling interval, the temperature cooling from 55° C. to 20° C. by a rate of 3-5° C./hour; in the third cooling interval, the temperature cooling from 20° C. to the temperature between 0 and 4° C. by a rate of 5-6° C./hour. |
