racemic-3,4-dihydro-7-(phenylmethoxy)-2H-1-benzopyran-2-carboxaldehyde → racemic-5-[3,4-dihydro-7-(phenylmethoxy)-2H-1-benzopyran-2-yl]-2,4-pentadienoic acid ethyl ester

HRID 2232500Notes

Reaction equation

HRID 2232500 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]([CH:17]=O)[O:16][C:11]=3[CH:10]=2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.C1(P(C2C=CC=CC=2)(C2C=CC=CC=2)=[CH:28][CH:29]=[CH:30][C:31]([O:33][CH2:34][CH3:35])=[O:32])C=CC=CC=1>C1(C)C=CC=CC=1>[CH2:34]([O:33][C:31](=[O:32])[CH:30]=[CH:29][CH:28]=[CH:17][CH:15]1[CH2:14][CH2:13][C:12]2[CH:19]=[CH:20][C:9]([O:8][CH2:7][C:1]3[CH:2]=[CH:3][CH:4]=[CH:5][CH:6]=3)=[CH:10][C:11]=2[O:16]1)[CH3:35]

Participants

4

Reactant 2

HCID 14541228racemic-3,4-dihydro-7-(phenylmethoxy)-2H-1-benzopyran-2-carboxaldehydeHCID 54429692Ethyl 4-(triphenyl-lambda~5~-phosphanylidene)but-2-enoate

Product 1

HCID 54009400racemic-5-[3,4-dihydro-7-(phenylmethoxy)-2H-1-benzopyran-2-yl]-2,4-pentadienoic acid ethyl esterYield 30.2%

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 4.4 g (12 mmoles) of ethyl 4-(triphenylphosphoranylidene)-2-butenoate in 30 ml of toluene (3.5 hr at 100° C.). Chromatography of the crude product on 100 g of silica gel gave 1.1 g (30%) of racemic-5-[3,4-dihydro-7-(phenylmethoxy)-2H-1-benzopyran-2-yl]-2,4-pentadienoic acid ethyl ester (mixture of E- and Z-isomers) as a yellow oil eluted with toluene and 19:1 toluene-ethyl acetate.

Sources & evidence

ORD record
ord-a637375c93be4edfae62e15ceed4d738
Source dataset
uspto-grants-1988_11
Patent number
US04788214

Reaction notes

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