Phosphorus tribromide → Methyl cis-7-bromo-5-heptenoate

HRID 34716Notes

Reaction equation

HRID 34716 reaction equation
O[CH2:2]/[CH:3]=[CH:4]\[CH2:5][CH2:6][CH2:7][C:8]([O:10][CH3:11])=[O:9].P(Br)(Br)[Br:13]>>[Br:13][CH2:2]/[CH:3]=[CH:4]\[CH2:5][CH2:6][CH2:7][C:8]([O:10][CH3:11])=[O:9]

Participants

3

Reactant 2

HCID 24614Phosphorus tribromideHCID 15586879Methyl cis-7-Hydroxy-5-heptenoate

Product 1

HCID 11253002Methyl cis-7-bromo-5-heptenoate

Procedure

To 23.7 g of cis-7-hydroxy-5-heptenoic acid, methyl ester and 150 ml of hexanes under nitrogen at 0° C. was added dropwise, 7.05 ml of phosphorous tribromide. After 2 hours the reaction was quenched with ice, diluted with hexanes, washed once with water and once with saturated aqueous bicarbonate, dried and stripped at reduced pressure. The crude product was dissolved in ether and filtered through a plug of silica gel. Removal of the ether at reduced pressure gave 31.4 g of the desired compound. NMR: 5.95-5.35 ppm (2H, m, olefins), 3.95 ppm (2H, d, 7 Hz, BrCH2), 3.65 ppm (3H, s, OMe), 2.45-2.05 ppm (4H, m, CH2 --CH2), 1.8 ppm (2H, q, 7 Hz, CH2).

Workup

  1. customAfter 2 hours the reaction was quenched with ice
  2. additiondiluted with hexanes
  3. washwashed once with water and once with saturated aqueous bicarbonate
  4. customdried
  5. dissolutionThe crude product was dissolved in ether
  6. filtrationfiltered through a plug of silica gel
  7. customRemoval of the ether at reduced pressure

Sources & evidence

ORD record
ord-950304421539425cbcaa81af77a7b609
Source dataset
uspto-grants-1988_08
Patent number
US04762935

Reaction notes

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