Sulfuric Acid → 1-(4-Bromophenyl)propan-2-one

HRID 514109

Reaction equation

HRID 514109 reaction equation
[Br:1][C:2]1[CH:7]=[CH:6][C:5]([CH2:8][C:9]([CH3:16])=[CH:10][C:11]([O:13]CC)=O)=[CH:4][CH:3]=1.[OH:17]S(O)(=O)=O>>[Br:1][C:2]1[CH:3]=[C:4]2[C:5]([CH:8]=[C:9]([CH3:16])[CH:10]=[C:11]2[OH:13])=[CH:6][CH:7]=1.[Br:1][C:2]1[CH:7]=[CH:6][C:5]([CH2:8][C:9](=[O:17])[CH3:16])=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 1118Sulfuric AcidHCID 67126147Ethyl 4-(4-bromophenyl)-3-methylbut-2-enoate

Product 2

HCID 7363321-(4-Bromophenyl)propan-2-oneHCID 671262827-Bromo-3-methylnaphthalen-1-ol

Conditions

Temperature
50 °C

Procedure

A flask containing the crude ethyl 4-(4-bromophenyl)-3-methylbut-2-enoate from above (˜30 grams) was treated with concentrated H2SO4 (120 mL) and warmed to 50° C. for 2.5 h. The reaction was poured onto ˜500 mL of crushed ice. Once the ice had thawed, the brown suspension was extracted with two portions of EtOAc (500 mL and 100 mL, respectively). The two extracts were combined, washed with saturated NaHCO3, dried (MgSO4), filtered, and concentrated to ˜55 mL. The residue was treated with DCM and wet-loaded onto a silica gel column and purified by flash chromatography (ethyl acetate/hexanes) giving the desired product (16.6 g, 60% yield over 2 steps from 1-(4-bromophenyl)propan-2-one. 1H NMR (400 MHz, CDCl3) δ 8.29 (d, J=1.9 Hz, 1H), 7.57 (d, J=8.6 Hz, 1H), 7.50 (dd, J=8.6, 2.0 Hz, 1H), 7.17 (s, 1H), 6.67 (s, 1H), 2.42 (s, 3H).

Workup

  1. extractionthe brown suspension was extracted with two portions of EtOAc (500 mL and 100 mL
  2. washwashed with saturated NaHCO3
  3. dry with materialdried (MgSO4)
  4. filtrationfiltered
  5. concentrationconcentrated to ˜55 mL
  6. additionThe residue was treated with DCM and wet-loaded onto a silica gel column
  7. custompurified by flash chromatography (ethyl acetate/hexanes)

Sources & evidence

ORD record
ord-46eeb4e8af464da3816ed035a3e94581
Source dataset
uspto-grants-2015_08
Patent number
US09102614B2

Linked notes

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