Hydrochloric Acid → 5-Bromo-1,2,3,4-tetrahydronaphthalen-1-one

HRID 1354183Notes

Reaction equation

HRID 1354183 reaction equation
[Cl-].[Al+3].[Cl-].[Cl-].[C:5]1(=[O:15])[C:14]2[C:9](=[CH:10][CH:11]=[CH:12][CH:13]=2)[CH2:8][CH2:7][CH2:6]1.[Br:16]Br.Cl>O>[Br:16][C:10]1[CH:11]=[CH:12][CH:13]=[C:14]2[C:9]=1[CH2:8][CH2:7][CH2:6][C:5]2=[O:15].[Br:16][C:12]1[CH:13]=[C:14]2[C:9]([CH2:8][CH2:7][CH2:6][C:5]2=[O:15])=[CH:10][CH:11]=1

Participants

7

Reactant 4

HCID 313Hydrochloric AcidHCID 107241-TetraloneHCID 24408BromineHCID 6451240Aluminum(III) Chloride2×

Product 2

HCID 2527317-Bromo-1,2,3,4-tetrahydronaphthalen-1-oneYield 42%HCID 108895725-Bromo-1,2,3,4-tetrahydronaphthalen-1-oneYield 51%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Conditions

Temperature
77.5 °C

Procedure

A 500 mL three-necked flask fitted with an addition funnel, reflux condenser and thermometer was charged with aluminum chloride (33.34 g, 250 mmol) and heated to 75-80° C. 1-Tetralone (14.6 g, 13.3 mL, 100 mmol) was added dropwise over 10 min. The resulting brown slurry was stirred for 3 min before dropwise addition of bromine (19.21 g, 6.15 ml, 120 mmol) over 15 min. The mixture was stirred for 5 min and then poured into a mixture of ice (300 g) and 12N HCl (40 mL). The mixture was stirred until the aluminum chloride was dissolved and then diluted with water (200 mL). The mixture was extracted with diethyl ether (3×300 mL) and the combined organics were washed with water (2×300 mL), dried (sodium sulfate), filtered and evaporated in vacuo to give a dark brown mixture of 5- and 7-bromo-1-tetralone. The isomers were separated using silica gel flash chromatography (Biotage Flash 75, elution solvent 20/1 hexanes:MTBE) to yield 5-bromo-1-tetralone (11.59 g, 51%) and 7-bromo-1-tetralone (9.45 g, 42%).

Workup

  1. customA 500 mL three-necked flask fitted with an addition funnel
  2. temperaturereflux condenser
  3. dissolutionwas dissolved
  4. extractionThe mixture was extracted with diethyl ether (3×300 mL)
  5. washthe combined organics were washed with water (2×300 mL)
  6. dry with materialdried (sodium sulfate)
  7. filtrationfiltered
  8. customevaporated in vacuo
  9. customto give
  10. customThe isomers were separated
  11. washsilica gel flash chromatography (Biotage Flash 75, elution solvent 20/1 hexanes:MTBE)

Sources & evidence

ORD record
ord-8d0f5b7fa6e048b59518f176fb5c51e3
Source dataset
uspto-grants-2007_05
Patent number
US07223774B2

Reaction notes

Loading…