Reaktion #49157

Reaktionsgleichung

N-Boc-L-proline

ethyl 3-(4-bromophenyl)-3-oxopropanoate

NBS

Hunig's base

Ethyl 2-bromo-3-(4-bromophenyl)-3-oxopropanoate

→

(2S)-2-(1-(4-bromophenyl)-3-ethoxy-1,3-dioxopropan-2-yl) 1-tert-butyl pyrrolidine-1,2-dicarboxylate

Lösungsmittel

acetonitrile

CH2Cl2

Reaktionsbedingungen

Aufarbeitung

1. 1
   WaschenThe reaction mixture was washed with NaHCO3 solution, brine
2. 2
   Trocknendried (MgSO4)
3. 3
   Filtrationfiltered
4. 4
   Einengenconcentrated
5. 5
   Sonstigeto give a residue which
6. 6
   Sonstigewas not purified
7. 7
   workup.STIRRINGthe solution stirred 18 hr
8. 8
   SonstigeThe solvent was removed by rotary evaporation
9. 9
   Waschenwashed with 0.1 N HCl, and brine

Vorschrift

The ethyl 3-(4-bromophenyl)-3-oxopropanoate (15 g, 55 mmol) was dissolved in CH2Cl2 (600 mL) and freshly recrystallized NBS (9.8 g, 55 mmol) was added and the solution stirred 18 hr. The reaction mixture was washed with NaHCO3 solution, brine, and dried (MgSO4), filtered, and concentrated to give a residue which was not purified. Ethyl 2-bromo-3-(4-bromophenyl)-3-oxopropanoate (16.5 g, 48 mmol) and N-Boc-L-proline (10 g, 48 mmol) were taken up in acetonitrile (450 mL) and Hunig's base (16 mL, 95 mmol) was added and the solution stirred 18 hr. The solvent was removed by rotary evaporation and the residue taken up in ethyl acetate, washed with 0.1 N HCl, and brine. 1H NMR (300 MHz, DMSO-d6) δ 7.95 (d, J=8.4 Hz, 2H), 7.79 (d, J=8.4 Hz, 2H), 6.68-6.65 (m, 1H), 4.39-4.30 (m, 1H), 4.21-4.12 (m, 2H), 2.27-2.21 (m, 1H), 2.0-1.95 (m, 1H), 1.90-1.76 (m, 2H), 1.39 (s, 2H), 1.31 (s, 9H), 1.11 (t, J=7.3 Hz, 3H).

Quelle