The invention belongs to the technical field of compound preparation, and particularly provides a preparation method of L-
glutamic acid-1-tert-butyl ester, which comprises the following steps: step S1, carrying out imidization reaction on an L-
glutamic acid-5-methyl ester compound and
benzophenone imine to generate N-dibenzylidene-L-
glutamic acid-5-methyl ester; step S2, enabling the N-dibenzylidene-L-glutamic acid-5-methyl ester and
tertiary butyl-2, 2, 2-
trichloroacetic acid imine ester to be subjected to a tert-butyl
esterification reaction, so as to generate N-dibenzylidene-L-glutamic acid-5-methyl ester-1-tert-butyl ester, and enabling the N-dibenzylidene-L-glutamic acid-5-methyl ester-1-tert-butyl ester to be subjected to a tert-butyl
esterification reaction; and S3, carrying out
hydrolysis reaction on the N-dibenzylidene-L-glutamic acid-5-methyl ester-1-tert-butyl ester to remove a methyl ester group, and removing a
protecting group on an amino group, so as to generate the L-glutamic acid-1-tert-butyl ester. The preparation method disclosed by the embodiment of the invention is used for preparing the L-glutamic acid-5-methyl ester-1-tert-butyl ester from the N-dibenzylidene-L-glutamic acid-5-methyl ester-1-tert-butyl ester. According to the application, the
tertiary butyl-2, 2, 2-
trichloroacetic acid imine ester is used for carrying out the tert-butyl
esterification reaction, so that the yield is high, the reaction condition is mild, the post-treatment is simple, the control on the generation of glutamic acid, pyroglutamic acid and pyroglutamic acid tert-butyl ester is facilitated, and the impurities are few.