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ChemicalBook CAS DataBase List 1-Bromo-4-chlorobutane
6940-78-9

1-Bromo-4-chlorobutane synthesis

9synthesis methods
1-Bromo-4-chlorobutane was prepared from 1,4-Dichlorobutane with 1,4-dibromo-butane by stirring in DMF with tetrabutylammomium bromide for 19.5 h at 100℃.
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Yield:6940-78-9 32%

Reaction Conditions:

Stage #1: benzyloxyacetic acidwith n-butyllithium;diisopropylamine in tetrahydrofuran;hexane at -70 - -30; for 1 h;
Stage #2: 1.3-chlorobromopropane in tetrahydrofuran;hexane at -70 - 20; for 2.5 h;

Steps:

18.18a

To a solution of diisopropylamine (1.1 mL, 8.0 mmol) in THF (10 mL) was added dropwise n-butyllithium 1.6 M hexane solution (5.0 mL, 8.0 mmol) at -30°C, and the mixture was stirred at the same temperature for 30 min. Thereto was added dropwise a solution of (benzyloxy)acetic acid (0.60 g, 3.6 mmol) in THF (5 mL) at -70°C, and the mixture was stirred at the same temperature for 30 min. Further, at the same temperature, 1-bromo-3-chloropropane (3.6 mL, 36 mmol) was added, and the mixture was stirred at the same temperature for 30 min and then at room temperature for 2 hr. The reaction mixture was added to ice-cooled water, and the mixture was washed with ethyl acetate. The aqueous layer was adjusted to pH 3 - 4 with 6 M hydrochloric acid, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The obtained residue was purified by silica gel column chromatography (hexane/ethyl acetate=100/0 - 50/50) to give the title compound as a colorless oil (0.28 g, 32%). 1H NMR (CDCl3) δ: 1. 91 - 2.06 (4 H, m), 3.54 (2 H, t, J=5.1 Hz), 4.08 (1 H, t, J=6.6 Hz), 4.55 and 4.74 (2 H, d, J=11.4 Hz), 7.34 - 7.39 (5 H, m).

References:

EP2455380,2012,A1 Location in patent:Page/Page column 79

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