Reaktion #167936

Reaktionsgleichung

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

Ac2O

pyridine

→

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

Lösungsmittel

DCM

EtOAc

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeReaction
2. 2
   Waschenwashed with diluted HCl, brine
3. 3
   Trocknendried over Na2SO4
4. 4
   Einengenconcentrated
5. 5
   workup.ADDITIONResulting residue was treated with 1N NaOH in ether
6. 6
   Extraktionextracted with ether
7. 7
   Waschenwashed with brine
8. 8
   Trocknendried over Na2SO4
9. 9
   Einengenconcentrated
10. 10
    Sonstigepurified by FCC (0-10% MeOH in DCM)

Vorschrift

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)+.

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