Water → Phenacyl bromide

HRID 647154Notes

Reaction equation

HRID 647154 reaction equation
C(N(CC)CC)C.C(Br)C=C.N[C:13]1[C:18](Cl)=[CH:17][C:16]([C:20](=[O:23])[CH2:21][Br:22])=[CH:15][C:14]=1Cl.O>CN(C=O)C.C(Cl)(Cl)(Cl)Cl>[CH2:21]([Br:22])[C:20]([C:16]1[CH:17]=[CH:18][CH:13]=[CH:14][CH:15]=1)=[O:23]

Participants

7

Reactant 4

HCID 962WaterHCID 7841Allyl bromideHCID 8471TriethylamineHCID 30158971-(4-Amino-3,5-dichlorophenyl)-2-bromoethan-1-one

Product 1

HCID 6259Phenacyl bromideYield 85.1%

Reagents, catalysts & solvents 2

HCID 5943Carbon TetrachlorideSolventHCID 6228DimethylformamideSolvent2×

Procedure

Triethylamine (17.0 g, 0.168 mol) is added in one portion to allyl bromide (105.9 g, 0.875 mol) under a nitrogen atmosphere. The resulting white emulsion gives an exotherm to 70° C. and becomes a thick white solid mass within 5 minutes. The solution formed with the addition of ~100 ml of DMF is stirred for 1 hour at 70°-95° C. A solution of 4'-amino-2-bromo-3',5'-dichloroacetophenone (25.0 g, 0.088 mol) in 50 ml of DMF is added in one portion and the resulting brown reaction mixture is maintained at 80°-90° C. for 2 hours. The progress of the reaction is frequently checked by thin layer chromatography SiO2 /CH2Cl2 /hexanes (1/1)) since prolonged heating results in the decomposition of both starting material and products. The reaction mixture is poured into 1.51 of H2O and is stirred for 0.5 hours. After a second aqueous trituration, the residual brown semi-solids are stirred with ~150 ml of CCl4 for 0.5 hours to form a suspension. The yellowish-brown solids are collected by filtration and are air dried to give 14.9 g (59.6%) of recovered phenacyl bromide starting material. The CCl4 filtrate is stirred with MgSO4, filtered and concentrated to yield 9.42 g of a brown syrup. Gradient elution (hexanes/CH2Cl2 (10/0→8/2) flash chromatography on a 9"×2" column of Silica Gel 60 gives two major fractions:

Workup

  1. customThe resulting white emulsion gives an exotherm to 70° C.
  2. customwithin 5 minutes
  3. temperaturethe resulting brown reaction mixture is maintained at 80°-90° C. for 2 hours
  4. temperaturesince prolonged heating
  5. customresults in the decomposition of both starting material and products
  6. stirringis stirred for 0.5 hours
  7. customto form a suspension
  8. filtrationThe yellowish-brown solids are collected by filtration
  9. customdried

Sources & evidence

ORD record
ord-90c690feab1440c981e6be23e022b167
Source dataset
uspto-grants-1983_10
Patent number
US04407819

Reaction notes

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