Реакция #167936

Уравнение реакции

(R)-tert-butyl 2-methylpiperazine-1-carboxylate

Ac2O

pyridine

→

(R)-tert-butyl 4-acetyl-2-methylpiperazine-1-carboxylate

Растворители

DCM

EtOAc

Условия реакции

Обработка

1. 1
   ДругоеReaction
2. 2
   Промывкаwashed with diluted HCl, brine
3. 3
   Сушкаdried over Na2SO4
4. 4
   Концентрированиеconcentrated
5. 5
   workup.ADDITIONResulting residue was treated with 1N NaOH in ether
6. 6
   Экстракцияextracted with ether
7. 7
   Промывкаwashed with brine
8. 8
   Сушкаdried over Na2SO4
9. 9
   Концентрированиеconcentrated
10. 10
    Другоеpurified by FCC (0-10% MeOH in DCM)

Методика

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)+.

Источник