Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester → racemic-3,4-dihydro-7-(phenylmethoxy)-2H-1-benzopyran 2-propenoic acid ethyl ester

HRID 2231922Notes

Reaction equation

HRID 2231922 reaction equation
[C:1]1([CH2:7][O:8][C:9]2[CH:20]=[CH:19][C:12]3[CH2:13][CH2:14][CH:15](C=O)[O:16][C:11]=3[CH:10]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.[C:21]([CH:26]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)([O:23][CH2:24][CH3:25])=[O:22]>C1(C)C=CC=CC=1>[C:1]1([CH2:7][O:8][C:9]2[CH:20]=[CH:19][C:12]3[CH2:13][CH2:14][CH2:15][O:16][C:11]=3[CH:10]=2)[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=1.[CH2:24]([O:23][C:21](=[O:22])[CH:26]=[CH2:1])[CH3:25]

Participants

4

Reactant 2

HCID 70670Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl esterHCID 14541228racemic-3,4-dihydro-7-(phenylmethoxy)-2H-1-benzopyran-2-carboxaldehyde

Product 1

HCID 131715774racemic-3,4-dihydro-7-(phenylmethoxy)-2H-1-benzopyran 2-propenoic acid ethyl esterYield 176.3%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

Using the procedure of example 30, 2.7 g (10 mmoles) of the aldehyde product from example 83 was condensed with 3.7 g (10.6 mmoles) of (carbethoxymethylene)triphenylphosphorane, in 30 ml of toluene (1.5 hours at 100° C.). After chromatography of the crude product on 50 g of silica gel (eluting with toluene), there was obtained 3.0 g (88.8%) of racemic-3,4-dihydro-7-(phenylmethoxy)-2H-1-benzopyran-2-propenoic acid ethyl ester (mixture of E- and Z-isomers), as a pale-yellow oil.

Sources & evidence

ORD record
ord-7efa17bec73e4e62bd6b38bb0926977e
Source dataset
uspto-grants-1988_11
Patent number
US04785017

Reaction notes

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