反应详情

A mixture of (R)-tert-butyl 2-methylpiperazine-1-carboxylate (4.8 g, 23.97 mmol), Ac2O (3.39 mL, 36.0 mmol) and pyridine (3.88 mL, 47.9 mmol) in DCM (30 mL) was stirred at rt for 30 min. Reaction was diluted with EtOAc, washed with diluted HCl, brine and sat NaHCO3, brine, and dried over Na2SO4, concentrated. Resulting residue was treated with 1N NaOH in ether, extracted with ether, washed with brine, dried over Na2SO4, concentrated and purified by FCC (0-10% MeOH in DCM) to give (R)-tert-butyl 4-acetyl-2-methylpiperazine-1-carboxylate. 1H NMR (400 MHz, CD2Cl2) δ ppm 4.14-4.46 (m, 2 H) 3.74-3.91 (m, 1 H) 3.46-3.72 (m, 1 H) 2.92-3.35 (m, 2 H) 2.56-2.91 (m, 1 H) 2.05 (d, J=16.67 Hz, 3 H) 1.44 (s, 9 H) 1.03-1.18 (m, 3 H). MS (ESI+) m/z 243.2 (M+H)+.

1. customReaction
2. washwashed with diluted HCl, brine
3. dry with materialdried over Na2SO4
4. concentrationconcentrated
5. additionResulting residue was treated with 1N NaOH in ether
6. extractionextracted with ether
7. washwashed with brine
8. dry with materialdried over Na2SO4
9. concentrationconcentrated
10. custompurified by FCC (0-10% MeOH in DCM)