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ChemicalBook CAS DataBase List BOC-L-Methionine
2488-15-5

BOC-L-Methionine synthesis

10synthesis methods
L-Methionine

63-68-3

Di-tert-butyl dicarbonate

24424-99-5

BOC-L-Methionine

2488-15-5

Example 1 [0041] 7.2 g of L-methionine was dissolved in a solvent mixture of 50 mL of water and 50 mL of acetonitrile. To this solution was added 2 g of sodium hydroxide (0.05 mol). The reaction mixture was cooled to 0 °C, followed by the slow addition of 10.9 g of di-tert-butyl dicarbonate (0.05 mol). After addition, the reaction system was gradually warmed to room temperature (24-25 °C) and the reaction was continuously stirred for 12 hours. After completion of the reaction, the acetonitrile was removed by rotary evaporation. To the residual aqueous phase, potassium carbonate was added and the pH was adjusted to 12. The aqueous phase was extracted twice with 50 mL of dichloromethane and the organic phase was discarded. To the aqueous phase, 1 N hydrochloric acid was added dropwise and the pH was adjusted to 6. The aqueous phase was again extracted twice with 50 mL of dichloromethane, the organic phases were combined, washed with 50 mL of saturated sodium chloride solution, dried with anhydrous sodium sulfate, and concentrated under reduced pressure to give viscous Boc-L-methionine (11.4 g) in 95% yield. The product was characterized by 1H NMR (500 MHz, CDCl3): δ 11.62 (br, 1H), 6.91 (br, 1H), 4.40 (m, 1H), 2.52 (t, J = 4.8 Hz, 2H), 2.05 (s, 3H), 1.92-2.15 (m, 2H), 1.42 (s, 9H). Mass spectrometry (MS) showed a molecular ion peak (M + 1) of 250.

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Yield:2488-15-5 95%

Reaction Conditions:

with triethylamine;sodium hydroxide in water;acetonitrile at 0 - 25; for 12 h;

Steps:

1
Example 1[0040][0041] 7.2 g Methionine was dissolved in a mixture of 50 mL water and 50 mL acetonitrile. To this solution was added2 g NaOH (0.05 mol). The obtained mixture was cooled down to 0°C and then 10.9 g di-t-butyl dicarbonate (0.05 mol)was added. After addition, the mixture was warmed to room temperature (24-25°C) and reacted for 12 h. Acetonitrilewas removed by distillation. Potassium carbonate was added to the residue and the pH thereof was adjusted to 12. Afterextracted with 50 mL dichloromethane twice, the organic layers were discarded. To the aqueous layer was added 1 Ndilute hydrochloric acid to adjust the pH to 6. After extracted with 50 mL dichloromethane twice, the organic layers werecollected together and washed with 50 mL saturate solution of sodium chloride and then dried over anhydrous sodiumsulfate, followed by concentration to obtain a viscous product (11.4 g). The yield was 95%.1H NMR (500 MHz, CDCl3) δ 11.62 (br, 1 H), 6.91 (br, 1 H), 4.40 (m. 1H), 2.52 (t, J = 4.8 Hz, 2 H), 2.05 (s, 3H), 1.92~2.15(m. 2 H), 1.42 (s, 9 H). Ms (M++1): 250.

References:

Zhejiang Hisoar Pharmaceutical Co., Ltd;PAN, Xianhua;LI, Weijin;ZHANG, Qunhui;RUAN, Libo;YU, Wansheng;DENG, Fei;MA, Tianhua;HUANG, Mingwang;HE, Minhuan EP2647624, 2013, A1 Location in patent:Paragraph 0040; 0041

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