Hydrochloric Acid → 1-(6-Bromonaphthalen-2-yl)ethanone

HRID 1262975Notes

Reaction equation

HRID 1262975 reaction equation
[Br:1][C:2]1[CH:11]=[CH:10][C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[CH:3]=1.[C:12](Cl)(=[O:14])[CH3:13].[Al+3].[Cl-].[Cl-].[Cl-].Cl>[N+](C1C=CC=CC=1)([O-])=O>[C:12]([C:7]1[CH:6]=[CH:5][C:4]2[C:9](=[CH:10][CH:11]=[C:2]([Br:1])[CH:3]=2)[CH:8]=1)(=[O:14])[CH3:13]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 6367Acetyl chlorideHCID 113722-BromonaphthaleneHCID 6451240Aluminum(III) Chloride

Product 1

HCID 124330821-(6-Bromonaphthalen-2-yl)ethanoneYield 92%

Reagents, catalysts & solvents 1

HCID 7416NitrobenzeneSolvent2×

Conditions

Temperature
25 °C

Procedure

A solution of 14.7 (70.9 mmol) of 2-bromonaphthalene and 6.40 g (81.5 mmol) of acetyl chloride in 55 mL of nitrobenzene was added dropwise to a vigorously stirred solution of 10.4 g (78 mmol) of anhydrous AlCl3 in 25 mL of nitrobenzene at 25°-30° C. over a period of 1.3 h. After being stirred for 1 h more at 25° C., the reaction mixture was poured onto 200 g of ice and 30 mL of concentrated HCl. The product was extracted with Et2O (300, 200, and 100 mL). The extracts were washed with brine and saturated NaHCO3, dried (MgSO4), and concentrated at reduced pressure to afford a brownish oil. Short-path distillation (45°-55° C./25 mm) was used to remove nitrobenzene. The crystalline residue was dissolved in hot hexane (300 ml), filtered, and concentrated at reduced pressure to give 16.3 g (92% yield) of crude 2-acetyl-6-bromonaphthalene. Two crystallizations from hexane afforded 5.3 g (21% yield) of pure product, which had only one spot by TLC (10% EtOAc/hexane) Rf 0.22, mp 99°-101.5° C.; IR (mull) 1670, 1623, 1365, 1355, 1265, 1225, 1175, 880, 820, 800 cm-1 ; 1H NMR (CDCl3) δ 2.71 (s, 3, CH3CO), 7.5-8.2 (m, 4, 3,4,7,8-ArH), 8.03 (s, 1, 5-ArH), 8.44 (s, 1, 1-ArH).

Workup

  1. extractionThe product was extracted with Et2O (300, 200, and 100 mL)
  2. washThe extracts were washed with brine and saturated NaHCO3
  3. dry with materialdried (MgSO4)
  4. concentrationconcentrated at reduced pressure
  5. customto afford a brownish oil
  6. distillationShort-path distillation (45°-55° C./25 mm)
  7. customto remove nitrobenzene
  8. dissolutionThe crystalline residue was dissolved in hot hexane (300 ml)
  9. filtrationfiltered
  10. concentrationconcentrated at reduced pressure

Sources & evidence

ORD record
ord-8f045f04b7c346e09d87c0a8bc9f0026
Source dataset
uspto-grants-1984_06
Patent number
US04454341

Reaction notes

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