Hydrochloric Acid → 7-bromo-4,4,6-trimethyl-3,4-dihydro-2H-naphthalen-1-one

HRID 915176Notes

Reaction equation

HRID 915176 reaction equation
[O:1]=[C:2]1[C:11]2[C:6](=[CH:7][C:8]([CH3:12])=[CH:9][CH:10]=2)[C:5]([CH3:14])([CH3:13])[CH2:4][CH2:3]1.[Cl-].[Al+3].[Cl-].[Cl-].[Br:19]Br.Cl>ClCCl>[Br:19][C:9]1[CH:10]=[C:11]2[C:6]([C:5]([CH3:14])([CH3:13])[CH2:4][CH2:3][C:2]2=[O:1])=[CH:7][C:8]=1[CH3:12]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 24408BromineHCID 6451240Aluminum(III) ChlorideHCID 134632674,4,6-Trimethyl-1,2,3,4-tetrahydronaphthalen-1-one

Product 1

HCID 121061407-bromo-4,4,6-trimethyl-3,4-dihydro-2H-naphthalen-1-oneYield 64%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

A solution of 1-oxo-4,4,6-trimethyl-1,2,3,4-tetrahydronaphthalene (40.0 g, 212 mmol) in dichloromethane (80 mL) was added dropwise at room temperature under argon with vigourous stiring to a suspension of aluminum chloride (56 g, 424 mmol) in dichloromethane (80 mL). Bromine (13 mL, 254 mmol) was then added slowly. The reaction mixture was stirred for 1.5 hours then poured into concentrated hydrochloride acid (6N, 300 mL) and extracted with ether. The organic layer was washed with water, aq NaHCO3, water, brine and dried (Mg2SO4). The residue was purified on silica gel (eluent: 5 to 8% ethyl acetate in hexane) to give 32.2 g of 7-bromo-1-oxo-4,4,6-trimethyl-1,2,3,4-tetrahydronaphthalene (64%). 1H NMR (300 MHz; CDCl3): 1.32 (s, 6 H), 1.94 (t, J=6.9 Hz, 2 H), 2.38 (s, 3 H), 2.64 (t, J=6.6 HZ, 2 H), 7.23 (s, 1 H), 8.06 (s, 1 H).

Workup

  1. extractionextracted with ether
  2. washThe organic layer was washed with water, aq NaHCO3, water, brine
  3. dry with materialdried (Mg2SO4)
  4. customThe residue was purified on silica gel (eluent: 5 to 8% ethyl acetate in hexane)

Sources & evidence

ORD record
ord-a9c3d4fa483a43948fb06e1746006165
Source dataset
uspto-grants-2007_09
Patent number
US07265139B2

Reaction notes

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