Iodine → 4,4'-Dibromostilbene

HRID 1904991Notes

Reaction equation

HRID 1904991 reaction equation
C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.[Br:20][C:21]1[CH:28]=[CH:27][C:24]([CH2:25]Br)=[CH:23][CH:22]=1.[O-]CC.[Na+].[Br:33][C:34]1[CH:41]=[CH:40][C:37]([CH:38]=O)=[CH:36][CH:35]=1.II>C(O)C.C1(C)C(C)=CC=CC=1>[Br:20][C:21]1[CH:28]=[CH:27][C:24]([CH:25]=[CH:38][C:37]2[CH:40]=[CH:41][C:34]([Br:33])=[CH:35][CH:36]=2)=[CH:23][CH:22]=1

Participants

8

Reactant 5

HCID 807IodineHCID 11776TriphenylphosphineHCID 685274-Bromobenzyl bromideHCID 707414-BromobenzaldehydeHCID 2723922Sodium ethoxide

Product 1

HCID 533959814,4'-Dibromostilbene

Reagents, catalysts & solvents 2

HCID 702EthanolSolvent2×HCID 7237O-XyleneSolvent

Conditions

Temperature
48 °C

Procedure

Into a reaction flask equipped with a mechanical stirrer, condenser, drying tube and thermometer was charged 76.8 grams (0.15 moles) of the triphenylphosphine salt of p-bromobenzyl bromide prepared in Part A and 11.1 grams (0.159 mole) of sodium ethoxide in 150 milliliters of absolute ethanol. Over a ten minute period, 30.0 grams (0.162 mole, Aldrich, 99 percent) of 4-bromobenzaldehyde in 30 milliliters of absolute ethanol was added to the reaction mixture at a reaction temperature of from 30° C. to 43° C. The 4-bromobenzaldehyde was washed into the reaction flask with 10 milliliters of absolute ethanol. The reaction mixture was then heated to a temperature of 48° C. and maintained at this temperature with continuous stirring overnight. The reaction was quenched by adding 140 milliliters of distilled water to the reaction flask. A soft cream colored precipitate formed in the reaction flask which was filtered and the collected solids dried to give 15.5 grams of a crude product fraction. This crude product fraction was heated to a temperature of 122° C.-128° C. in xylene with a small crystal of iodine, cooled to ambient temperature, filtered and the collected solids were dried in a vacuum oven to give 11.2 grams of 4,4'-dibromostilbene having a melting point of from 211° -213° C.

Workup

  1. customInto a reaction flask equipped with a mechanical stirrer, condenser
  2. customdrying tube
  3. washThe 4-bromobenzaldehyde was washed into the reaction flask with 10 milliliters of absolute ethanol
  4. temperaturemaintained at this temperature
  5. customThe reaction was quenched
  6. additionby adding 140 milliliters of distilled water to the reaction flask
  7. customA soft cream colored precipitate formed in the reaction flask which
  8. filtrationwas filtered
  9. customthe collected solids dried
  10. customto give 15.5 grams of a crude product fraction
  11. temperaturecooled to ambient temperature
  12. filtrationfiltered
  13. customthe collected solids were dried in a vacuum oven

Sources & evidence

ORD record
ord-f1ea3a01e6b84110b277767e7d588ab2
Source dataset
uspto-grants-1989_06
Patent number
US04841009

Reaction notes

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