Phosphorus sulfide (P2S5) → Phenylmethyl (3S)-3-({[(1,1-dimethylethyl)oxy]carbonyl}amino)-4-(methylamino)-4-thioxobutanoate

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Reaction Steps

Phenylmethyl N2-{[(1,1-dimethylethyl)oxy]carbonyl}-N1-methyl-L-α-asparaginate (4.20 g, 12.48 mmol) and phosphorus pentasulfide (3.33 g, 7.49 mmol) were dissolved in THF (105 mL) and the reagents were stirred at room temperature for 4 h. Saturated NaHCO3 was added and the reaction was extracted with EtOAc. The organic layer was concentrated and the residue was dissolved in CH2Cl2:Et2O (1:1) and filtered through a well packed silica gel column to give the titled product (3.3 g, 75%) as a white solid. 1H-NMR (CDCl3) δ: 1.461 (9H, s), 2.960 (1H, m), 3.149 (3H, d, J=5.2 Hz), 3.270 (1H, m), 4.820 (1H, s), 5.137 (2H, m), 5.770 (1H, s), 7.374 (5H, m), 8.380 (1H, s). LC-MS (ES) m/e 353.6 (M+H)+.

Provenance & Evidence