ChemicalBook CAS DataBase List 4-Bromobutyric acid

4-Bromobutyric acid synthesis

14synthesis methods

Product Name:4-Bromobutyric acid
CAS Number:2623-87-2
Molecular formula:C4H7BrO2
Molecular Weight:167

4-Bromobutyric acid may be produced by a reaction of Y-butyrolactone with hydrogen bromide. The hydrogen bromide to be used may be gas or an aqueous Solution thereof. The reaction temperature is usually about 10 to 100°C., and the amount of hydrogen bromide to be used is usually about 1 to 10 moles per mole of Y-butyrolactone.

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2623-87-2
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Yield:2623-87-2 65%

Reaction Conditions:

with sulfuric acid;hydrogen bromide in water; for 12 h;Inert atmosphere;Reflux;

Steps:

Synthesis of 4-bromobutanoic acid (4a) and 6-bromohexanoic acid (4b)

General procedure: Typical procedure: Under a dry argon atmosphere, 48% HBr aqueous solution (41.0mL, 360mmol) and conc. sulfuric acid (9.6mL) were added dropwise to γ-butyrolactone (3a) (6.10g, 70.9mmol), and the resulting mixture was left undisturbed at room temperature for 2h. Then, after refluxing for 12h, the reaction mixture was cooled to room temperature. To this reaction mixture, 192mL of water was added, and the crude product was extracted with diethyl ether. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, and filtered. The filtrate was concentrated under reduced pressure. The residue was purified by silica gel chromatography eluted with a mixed solvent of ethyl acetate/hexane (1/2v/v). The fraction with an R_f value of 0.44 was collected and dried under reduced pressure to afford 4-bromobutanoic acid (4a) as yellow oil (7.638g, 65%). ¹H NMR (400MHz, CDCl₃, ppm): δ 2.19 (quint, J=6.4Hz, 2H, BrCH₂CH₂), 2.58 (t, J=4.2Hz, 2H, CH₂COOH), and 3.48 (t, J=3.2Hz, 2H, BrCH₂). ¹³C NMR (100MHz, CDCl₃, ppm): δ 27.36 (BrCH₂CH₂), 32.11 (BrCH₂), 32.38 (Br(CH₂)₂CH₂), and 178.58 (COOH). IR (NaCl, cm^-1): 1711 (C=O), 3046 (-OH).