Triethylamine → 2-Bromo-4-methylpentanoic acid, 2,6-dimethoxy-4-methylphenyl ester

HRID 1280832Notizen

Reaktionsgleichung

Reaktionsgleichung von HRID 1280832
[Br:1][CH:2]([CH2:6][CH:7]([CH3:9])[CH3:8])[C:3](Cl)=[O:4].[CH3:10][O:11][C:12]1[CH:17]=[C:16]([CH3:18])[CH:15]=[C:14]([O:19][CH3:20])[C:13]=1[OH:21].C(N(CC)CC)C>ClCCl>[Br:1][CH:2]([CH2:6][CH:7]([CH3:9])[CH3:8])[C:3]([O:21][C:13]1[C:14]([O:19][CH3:20])=[CH:15][C:16]([CH3:18])=[CH:17][C:12]=1[O:11][CH3:10])=[O:4]

Komponenten

5

Edukt 3

HCID 8471TriethylamineHCID 2409254-Methyl-2,6-dimethoxyphenolHCID 135203652-Bromo-4-methylpentanoyl chloride

Produkt 1

HCID 914332632-Bromo-4-methylpentanoic acid, 2,6-dimethoxy-4-methylphenyl esterAusbeute 76,1 %

Reagenzien, Katalysatoren, Lösungsmittel 1

HCID 6344DichloromethaneLösungsmittel2×

Versuchsvorschrift

A solution of sodium nitrite (31.55 g) in water (70 ml) was added dropwise to a stirred solution of D-leucine (20 g) in 47% aqueous hydrobromic acid (140 ml)/water (211 ml) at 0° C. The reaction mixture was allowed to warm to room temperature and stirred for 20 hours, then diluted with diethyl ether (600 ml). The organic layer was separated and washed with aqueous sodium metabisulphite (200 ml), dried over sodium sulphate, filtered and the solvent removed under reduced pressure to give 2-bromo-4-methyl-pentanoic acid as a yellow oil (27.6 g) [1H NMR (CDCl3): δ0.93 (d, 3H), 0.98 (d, 3H), 1.75-1.85 (m, 1H), 1.91-1.95 (m, 2H), 4.30 (t, 1H)]. Oxalyl chloride (9.56 ml) was added dropwise to a stirred solution of the 2-bromo-4-methylpentanoic acid (10.7 g) and pyridine (0.1 ml) in dichloromethane (60 ml). The reaction mixture was stirred for 20 hours and the solvent was removed under reduced pressure to give 2-bromo-4-methylpentanoyl chloride (12 g) [1H NMR (CDCl3); δ0.95 (d, 3H), 1.01 (d, 3H), 1.80-2.07 (m, 3H), 4.52 (t, 1H)]. A solution of this 2-bromo-4-methylpentanoyl chloride (12 g) in dichloromethane (40 ml) was added dropwise to a stirred solution of 2,6-dimethoxy-4-methylphenol (9.41 g) and triethylamine (15.6 ml) in dichloromethane (20 ml). The reaction mixture was stirred for 20 hours and was then chromatographed on silica gel, eluting with dichloromethane, to give the title compound as a viscous yellow oil (14.7 g).

Aufarbeitung

  1. customwas then chromatographed on silica gel
  2. washeluting with dichloromethane

Quellen und Nachweise

ORD-Eintrag
ord-8784cf2a40844f5f833b27f84f3d6e0e
Quelldatensatz
uspto-grants-2002_09
Patentnummer
US06451854B1

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