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ChemicalBook CAS DataBase List BOC-HYP-OL
61478-26-0

BOC-HYP-OL synthesis

12synthesis methods
N-Boc-trans-4-Hydroxy-L-proline methyl ester

74844-91-0

BOC-HYP-OL

61478-26-0

Under argon protection, 1-tert-butyl 2-methyl-(2S,4R)-4-hydroxypyrrolidine-1,2-dicarboxylate (5.0 g, 20.41 mmol) was dissolved in THF (100 mL), cooled to -16 °C and stirred. LiAlH4 (1 M solution of THF, 21 mL, 21 mmol) was added slowly and dropwise over 5 min and precipitate formation was observed in the reaction. THF (50 mL) was subsequently added to destroy the precipitate. The reaction mixture was gradually warmed to 0 °C with stirring for 3.5 hours. Upon completion of the reaction, the reaction was quenched with EtOAc (5 mL) and stirring was continued for 30 minutes. Then, an excess of Rochelle's salt solution (100 mL) was carefully added, and the mixture was warmed to room temperature and stirred for an additional 1 hour. The mixture was extracted twice with CH2Cl2 (100 mL), the organic phases were combined, dried with MgSO4, filtered and concentrated under reduced pressure to remove the solvent. The product was purified by column chromatography (eluent: 10% MeOH/CH2Cl2) to give Intermediate 19 in quantitative yield.1H NMR (300 MHz, DMSO-d6) δ: 4.82 (br s, 1H), 4.64 (br d, J = 5.5 Hz, 1H), 4.20 (sxt, J = 4.2 Hz, 1H), 3.75 (br s , 1H), 3.16-3.50 (m, 4H), 1.85-2.02 (m, 1H), 1.80 (br s, 1H), 1.39 (s, 9H).

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Yield:61478-26-0 100%

Reaction Conditions:

with lithium aluminium tetrahydride in tetrahydrofuran at -16; for 3.5 h;Inert atmosphere;

Steps:

19 Intermediate 19tert-Butyl (2S,4R)-4-hydroxy-2-(hydroxymethyl)pyrrolidine-1-carboxylate

To a stirred solution of 1 -tert-butyl 2-methyl (2S,4R)-4-hydroxypyrrolidine-1 2- dicarboxylate (5.0 g, 20.41 mmol) in THF (100 mL) under an argon atmosphere at -16°C was added LiAIH4 (1 M in THF, 21 mL, 21 mmol) dropwise over 5 mm.A precipitate was formed that was broken up by the addition of THF (50 mL). The reaction mixture was stirred for 3.5 h, during which time the temperature was allowed to warm to 0°C. The reaction was quenched by the addition of EtOAc (5 mL), and stirred for 30 mm. Excess Rochelles salt solution (100 mL) was carefully added and the reaction mixture allowed to warm to rt and stirredfor a further 1 h. The product was isolate by extraction twice with CH2CI2 (100 mL) and the combined organic fractions dried over Mg504, filtered and the solvent removed by evaporation in vacuo. Purification by column chromatography, 10% MeOH/CH2CI2, gave Intermediate 19 in quantitative yield. 1H NMR (300MHz, DMSO-d5) 0H. 4.82 (br 5, 1 H), 4.64 (br d, J=5.5 Hz, 1 H),4.20 (sxt, J=4.2 Hz, 1 H), 3.75 (brs, 1 H), 3.16-3.50 (m, 4 H), 1.85-2.02 (m, 1 H),1 .80 (br 5, 1 H), 1 .39 (5, 9 H).

References:

WO2017/29521,2017,A1 Location in patent:Page/Page column 37

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