ChemicalBook CAS DataBase List N-Boc-4-oxo-L-Proline methyl ester

N-Boc-4-oxo-L-Proline methyl ester synthesis

9synthesis methods

Product Name:N-Boc-4-oxo-L-Proline methyl ester
CAS Number:102195-80-2
Molecular formula:C11H17NO5
Molecular Weight:243.26

N-Boc-trans-4-Hydroxy-L-proline methyl ester

74844-91-0

102195-80-2

General procedure for the synthesis of BOC-4-oxo-L-proline methyl ester from N-Boc-trans-4-hydroxy-L-proline methyl ester: (a) To a solution of methyl (2S,4R)-1-Boc-4-hydroxypyrrolidine-2-carboxylate (40 g, 157 mmol) in dichloromethane (DCM, 500 mL) was added Days-Martin oxidizer (DMP, 80 g, 189 mmol) at 0 °C. The reaction mixture was stirred at room temperature for 4 h. Upon completion of the reaction, the reaction was quenched with sodium bisulfite (NaHSO3) solution. The reaction mixture was extracted with dichloromethane (DCM) and the organic phase was washed with aqueous sodium bicarbonate (NaHCO3) solution. Concentration of the organic phase afforded the title intermediate (2S)-1-tert-butoxycarbonyl-4-oxopyrrolidine-2-carboxylic acid methyl ester (33 g, 89% yield) as a colorless oil. 1H NMR (400 MHz, CDCl3): δ (ppm) 1.51 (s, 9H), 2.550-2.597 (d, 1H, J = 18.8Hz), 2.876-2.944 (t, 1H, J = 13.6Hz), 3.895 (s, 3H), 3.766-3.895 (m, 1H), 4.696- 4.814 (m, 1H).

74844-91-0 Synthesis

74844-91-0
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102195-80-2
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Yield:102195-80-2 98.17%

Reaction Conditions:

with 2,2,6,6-Tetramethyl-1-piperidinyloxy free radical;trichloroisocyanuric acid in dichloromethane at 0 - 20; for 0.5 h;

Steps:

43.A Step A:
To a solution of N-Boc-trans-4-hydroxyl-L-methyl prolinate (114.00 g, 464.79 mmol) in dichloromethane (1.2 L) was added trichloroisocyanuric acid(113.42 g, 488.03 mmol) and then TEMPO (1.46 g, 9.30 mmol) was added at 0 °C.
After stirring for 0.5 h at 10-20 °C, the mixture was filtered with kieselguhr.
The dichloromethane phase was washed with sat. aq K₂CO₃ (1000 mL) twice, then with sat.aq NaCl (800 mL), dried over anhydrous Na₂SO₄, filtered and the filtrate was concentrated in vacuo to give N-Boc- 4-oxo-L-methyl prolinate (111.00 g, 456.30 mmol, 98.17%).
¹H NMR (CDCl₃, 400 MHz): δ 4.81-4.64 (m, 1H), 3.84 (d, J = 7.8 Hz, 2H), 3.73 (s, 3H), 2.99-2.84 (m, 1H), 2.55 (d, J = 20.0 Hz, 1H), 1.43 (d, J = 8.0 Hz, 9H).

References:

Medshine Discovery Inc.;SUN, Fei;DING, Charles Z.;CAI, Zhe;QIAN, Wenyuan;HU, Guoping;LI, Jian;CHEN, Shuhui EP3450430, 2019, A1 Location in patent:Paragraph 0272; 0273

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