Uses
N-Cbz-L-tyrosine Methyl Ester is used in preparation of optically active Imidazolidione derivatives from N-Benzyloxycarbonyl-tyrosine Ester via Ethylation, reduction and successive treatment with Methanesulfonyl Chloride, Ethylenediamine and Lithium Hydroxide.
Synthesis
To the solid L-tyrosine methyl ester hydrochloride (Tyr-OMe-HCl) obtained above, 300 g of ethyl acetate (AcOEt) was added, 100 g of sodium carbonate (Na2CO3) and 50 g of water under stirring. Benzyl chloroformate (Z-Cl) was slowly added dropwise while controlling the pH of the reaction system to 8. The progress of the reaction was monitored by thin layer chromatography (TLC) until the reaction system was free of L-tyrosine methyl ester hydrochloride (Tyr-OMe-HCl). Subsequently, citric acid was added to acidify the reaction solution to pH=3 and the layers were left to separate. The organic layer was washed to neutrality with brine. To the organic layer 20-50 g of anhydrous sodium sulfate (Na2SO4) was added and stirred for 4 hours for drying. The sodium sulfate (Na2SO4) was removed by filtration and the filtrate was concentrated and transferred to a crystallization kettle. Concentrate the concentrate with hot water until dry, add 200g of petroleum ether (PET), stirring until crystallization is complete. White crystals of N-Benzyloxycarbonyl-L-tyrosine methyl ester (ZL-Tyr-OMe) were obtained by filtration and dried to give 390 g of product with 4% moisture content.
References
[1] Journal of the American Chemical Society, 2004, vol. 126, # 32, p. 10162 - 10173
[2] Croatica Chemica Acta, 2003, vol. 76, # 1, p. 23 - 36
[3] Journal of Organic Chemistry, 1986, vol. 51, # 14, p. 2728 - 2735
[4] Journal of the American Chemical Society, 2004, vol. 126, # 40, p. 12897 - 12906
[5] Patent: CN103833593, 2016, B. Location in patent: Paragraph 0045; 0047
