Phenyltrimethylammonium bromide dibromide → 2-Bromo-1-(3,5,5-trimethyl-4,5,6,7-tetrahydro-benzo[c]thiophen-1-yl)-ethanone

HRID 1665953Notes

Reaction equation

HRID 1665953 reaction equation
[CH3:1][C:2]1[S:6][C:5]([C:7]([OH:9])=O)=[C:4]2[CH2:10][CH2:11][C:12]([CH3:15])([CH3:14])[CH2:13][C:3]=12.[Br-:16].[Br-].[Br-].[C:19]1([N+](C)(C)C)C=CC=CC=1.C1([N+](C)(C)C)C=CC=CC=1.C1([N+](C)(C)C)C=CC=CC=1>C1COCC1.CO>[Br:16][CH2:19][C:7]([C:5]1[S:6][C:2]([CH3:1])=[C:3]2[CH2:13][C:12]([CH3:15])([CH3:14])[CH2:11][CH2:10][C:4]=12)=[O:9]

Participants

5

Reactant 2

HCID 17977687Phenyltrimethylammonium bromide dibromideHCID 57508884HCID 57508884, compound

Product 1

HCID 575089072-Bromo-1-(3,5,5-trimethyl-4,5,6,7-tetrahydro-benzo[c]thiophen-1-yl)-ethanoneYield 80%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 8028TetrahydrofuranSolvent

Procedure

To a solution of 1-(3,5,5-trimethyl-4,5,6,7-tetrahydro-benzo[c]thiophen-1-yl)-ethanone (1.18 g, 5.31 mmol, Example C) in THF (60 mL) and methanol (6 mL), phenyltrimethylammonium bromide dibromide (2.0 g, 5.31 mmol) is added in portions. Upon complete addition, the mixture is stirred at it for 30 min before the solvent is evaporated. The crude product is purified by prep. HPLC (Grom-Sil 120 ODS-4-HE, 30×75 mm, 10 μm, 20-95% acetonitrile in water containing 0.5% formic acid) to give 2-bromo-1-(3,5,5-trimethyl-4,5,6,7-tetrahydro-benzo[c]thiophen-1-yl)-ethanone (1.28 g) as a colourless oil; 1H NMR (CDCl3): δ 4.24 (s, 2H), 3.03 (t, J=7.0 Hz, 2H), 2.36 (s, 3H), 2.30 (s, 2H), 1.54 (t, J=7.0 Hz, 2H), 0.98 (s, 6H).

Workup

  1. additionUpon complete addition
  2. customis evaporated
  3. customThe crude product is purified by prep

Sources & evidence

ORD record
ord-70448ddc6199437b8fd8cb5e39e92b2c
Source dataset
uspto-grants-2011_10
Patent number
US08039644B2

Reaction notes

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