Preparation method of N-fluorenylmethoxycarbonyl-S-(4-methoxytribenzyl)-L-homocysteine

The invention relates to a preparation method of N-fluorenylmethoxycarbonyl-S-(4-methoxytribenzyl)-L-homocysteine, and solves the technical problem that there is no effective synthesis method in the prior art. The preparation method comprises following steps: (1) dissolving L-methionine into a solvent, and under the action of a strong reducing agent, removing one methyl group to prepare a crude product of L-homocysteine; (2) dissolving the crude product of L-homocysteine and 4-methoxytriphenyl chloromethane into a solvent, slowly adding a strong acid, TLC monitoring the reactions for 12 to 24 hours, carrying out suction filtration, adjusting the pH to 7 by an alkaline solution, carrying out suction filtration, and washing the obtained solid by a solvent to obtain S-(4-methoxytribenzyl)-L-homocysteine; and (3) dissolving S-(4-methoxytribenzyl)-L-homocysteine into a solvent, adding a fluorenylmethoxycarbonyl protective group onto S-(4-methoxytribenzyl)-L-homocysteine, TLC monitoring the reactions for 6 to 10 ho