Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester → HCID 14329878, compound

HRID 2231909Notes

Reaction equation

HRID 2231909 reaction equation
[C:1]1([CH2:7][O:8][C:9]2[CH:10]=[CH:11][C:12]3[O:17][CH:16](O)[CH2:15][CH2:14][C:13]=3[CH:19]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[C:20]([CH:25]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)([O:22][CH2:23][CH3:24])=[O:21]>C1(C)C=CC=CC=1>[CH2:23]([O:22][C:20](=[O:21])[CH2:25][CH:16]1[CH2:15][CH2:14][C:13]2[CH:19]=[C:9]([O:8][CH2:7][C:1]3[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=3)[CH:10]=[CH:11][C:12]=2[O:17]1)[CH3:24]

Participants

4

Reactant 2

HCID 70670Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl esterHCID 14329763HCID 14329763, compound

Product 1

HCID 14329878HCID 14329878, compoundYield 74.2%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent2×

Procedure

A solution of 1.8 g of racemic-3,4-dihydro-6-(phenylmethoxy)-2H-1-benzopyran-2-ol and 2.6 g of (carbethoxymethylene)triphenylphosphorane in 20 ml of toluene was stirred and refluxed for 22 hours. The solution was cooled and placed on a column of 50 g of silica gel packed in toluene. Elution with toluene and 19:1 toluene-ethyl acetate gave 1.7 g (74.2%) of racemic-3,4-dihydro-6-(phenylmethoxy)-2H-1-benzopyran-2-acetic acid ethyl ester as a pale-yellow oil. This material was dissolved in 25 ml of absolute ethanol and the solution was stirred in the presence of 0.2 g of 10% palladium on carbon, at room temperature, in an atmosphere of hydrogen. After 1.5 hours, hydrogen uptake ceased and the catalyst was removed by filtration. The filtrate was concentrated in vacuo to give 1.2 g (97.6%) of racemic-3,4-dihydro-6-hydroxy-2H-1-benzopyran-2-acetic acid ethyl ester as a pale-yellow oil.

Workup

  1. temperaturerefluxed for 22 hours
  2. temperatureThe solution was cooled
  3. washElution with toluene and 19:1 toluene-ethyl acetate

Sources & evidence

ORD record
ord-1a69b985cc384953a475924cd28d8ca3
Source dataset
uspto-grants-1988_11
Patent number
US04785017

Reaction notes

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