1,4-Dibromobutane → HCID 57242902, Verbindung

HRID 650143

Reaktionsgleichung

Reaktionsgleichung von HRID 650143
C([Li])CCC.[CH2:6]([O:8][C:9]1[C@H:10]([CH:18]([CH3:20])[CH3:19])[N:11]=[C:12]([O:15][CH2:16][CH3:17])[CH2:13][N:14]=1)[CH3:7].[Br:21][CH2:22][CH2:23][CH2:24][CH2:25]Br>O1CCCC1.C(OCC)C>[CH2:6]([O:8][C:9]1[C@H:10]([CH:18]([CH3:20])[CH3:19])[N:11]=[C:12]([O:15][CH2:16][CH3:17])[C@@H:13]([CH2:25][CH2:24][CH2:23][CH2:22][Br:21])[N:14]=1)[CH3:7]

Komponenten

6

Edukt 3

HCID 80561,4-DibromobutaneHCID 11020211(S)-2,5-Dihydro-3,6-diethoxy-2-isopropylpyrazineHCID 178418339Butyllithium

Produkt 1

HCID 57242902HCID 57242902, VerbindungAusbeute 57 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 3283Diethyl EtherLösungsmittelHCID 8028TetrahydrofuranLösungsmittel

Versuchsvorschrift

n-butyllithium (13.3 mL of a 1.6 M solution in hexanes,21.3 mmol) was added to a solution of (2S)-2,5-dihydro-3,6-diethoxy-2-isopropyl pyrazine (Schöllkopf reagent)(4.30 g, 20.3 mmol) in tetrahydrofuran (THF) over the course of five minutes. The solution was maintained at −78° C. for 15 minutes after which 1,4-dibromobutane (9.75 mL, 81.2 mmol) was added in a single portion. After 2.5 hours at −78° C. the reaction was allowed to warm to room temperature and diluted with diethyl ether (100 mL). The organic phase was washed with water (100 mL), brine (100 mL) and then dried with magnesium sulfate (MgSO4). Following filtration and concentration most of the residual 1,4-dibromobutane was removed under high vacuum. The remaining oil was purified by silica gel chromatography (2% ethyl acetate in hexanes) to provide 5 (3.7 g, 57%) as a colorless liquid;[α]25D−1.13° (c=4.5, CHCl3); IR (thin film) 2957, 1689, 1456, 1364, 1304, 1230, 1144, 1038 cm−1; 1H NMR(300 MHz, CDCl3) δ4.04-4.18 (m, 4H) 3.94-4.02 (m, 1H) 3.90 (t, J=3.9, 1H) 3.39 (t, J=6.9, 2H) 2.21-2.32 (m, 1H) 1.68-1.92 (m, 4H) 1.33-1.47 (m, 2H) 1.274 (t, J=7.2, 3H) 1.268 (t, J=7.2, 3H) 1.03 (d, J=6.9, 3H) 0.70 (d, J=6.9, 3H); 13C NMR (100.6 MHz, CDCl3) d 163.12, 163.05, 60.72, 60.48, 55.09, 33.60, 33.11, 32.66, 31.80, 23.22, 19.03, 16.6, 14.34, 14.31; Mass Spectrum (FAB+) 347.1 (MH+).

Aufarbeitung

  1. additionwas added in a single portion
  2. washThe organic phase was washed with water (100 mL), brine (100 mL)
  3. dry with materialdried with magnesium sulfate (MgSO4)
  4. filtrationfiltration and concentration most of the residual 1,4-dibromobutane
  5. customwas removed under high vacuum
  6. customThe remaining oil was purified by silica gel chromatography (2% ethyl acetate in hexanes)

Quellen und Nachweise

ORD-Eintrag
ord-6d166a1c760b4b7183b1146cfa41e80f
Quelldatensatz
uspto-grants-2001_08
Patentnummer
US06271198B1

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