Hydrogen Bromide → 2-Bromo-2-(4-methylthiophenyl)-1-(4-methylphenyl)ethanone

HRID 1378572Notes

Reaction equation

HRID 1378572 reaction equation
[CH3:1][S:2][C:3]1[CH:8]=[CH:7][C:6]([CH2:9][C:10]([C:12]2[CH:17]=[CH:16][C:15]([CH3:18])=[CH:14][CH:13]=2)=[O:11])=[CH:5][CH:4]=1.[BrH:19].BrBr>C(O)(=O)C>[Br:19][CH:9]([C:6]1[CH:5]=[CH:4][C:3]([S:2][CH3:1])=[CH:8][CH:7]=1)[C:10]([C:12]1[CH:13]=[CH:14][C:15]([CH3:18])=[CH:16][CH:17]=1)=[O:11]

Participants

5

Reactant 3

HCID 260Hydrogen BromideHCID 24408BromineHCID 538745302-(4-Methylthiophenyl)-1-(4-methylphenyl)ethanone

Product 1

HCID 537231142-Bromo-2-(4-methylthiophenyl)-1-(4-methylphenyl)ethanoneYield 64%

Reagents, catalysts & solvents 1

HCID 176Acetic AcidSolvent3×

Procedure

A 500 mL round-bottomed flask equipped with a pressure-equalizing addition funnel and provisions for magnetic stirring was charged with 2-(4-methylthiophenyl)-1-(4-methylphenyl)ethanone from Step 2 (10.0 g, 39.0 mmol), 33% HBr in acetic acid (70 mL) and glacial acetic acid (100 mL). Over approximately 20 minutes, a solution of bromine in acetic acid (1M, 39 mL) was added to the suspension, and the reaction was held at room temperature for one hour. Any undissolved solids were removed by filtration, and the reaction was concentrated in vacuo, to a residue. The residue was dissolved in methylene chloride (100 mL), washed with 5% Na2S2O5 (2×100 mL), dried over MgSO4, filtered, and concentrated in vacuo to a colorless oil. The oil was held under vacuum for 16 hours, yielding 2-bromo-2-(4-methylthiophenyl)-1-(4-methylphenyl)ethanone (8.38 g, 64%) as a dirty white solid: mp 97°-98° C. 1H NMR (CDCl3) 300 MHz 7.86 (d, J=8.46 Hz, 2H), 7.80(d, J=8.26 Hz, 2H), 7.33-7.16(m, 4H), 5.88(s, 1H), 2.43(s, 3H), 2.36(s, 3H).

Workup

  1. customA 500 mL round-bottomed flask equipped with a pressure-equalizing addition funnel
  2. waitthe reaction was held at room temperature for one hour
  3. customAny undissolved solids were removed by filtration
  4. concentrationthe reaction was concentrated in vacuo, to a residue
  5. dissolutionThe residue was dissolved in methylene chloride (100 mL)
  6. washwashed with 5% Na2S2O5 (2×100 mL)
  7. dry with materialdried over MgSO4
  8. filtrationfiltered
  9. concentrationconcentrated in vacuo to a colorless oil
  10. waitThe oil was held under vacuum for 16 hours

Sources & evidence

ORD record
ord-633c4b4cdd1642bcad87e11d879d4c89
Source dataset
uspto-grants-1997_09
Patent number
US05668161

Reaction notes

Loading…