Ethyl 4-(2-(3,4-dihydro-4,4-dimethyl-2H-1 benzopyran-6-yl)-1-propenyl)benzoate → p-[(E)-2-(4,4-dimethyl-6-chromanyl)propenyl]benzyl alcohol

HRID 2118522Notes

Reaction equation

[CH3:1][C:2]1([CH3:26])[C:11]2[C:6](=[CH:7][CH:8]=[C:9](/[C:12](/[CH3:25])=[CH:13]/[C:14]3[CH:24]=[CH:23][C:17]([C:18](OCC)=[O:19])=[CH:16][CH:15]=3)[CH:10]=2)[O:5][CH2:4][CH2:3]1.[H-].C([Al+]CC(C)C)C(C)C.CO.O>CCOCC>[CH3:1][C:2]1([CH3:26])[C:11]2[CH:10]=[C:9](/[C:12](/[CH3:25])=[CH:13]/[C:14]3[CH:15]=[CH:16][C:17]([CH2:18][OH:19])=[CH:23][CH:24]=3)[CH:8]=[CH:7][C:6]=2[O:5][CH2:4][CH2:3]1

Participants

Conditions

Temperature: 0 °C

Procedure

4.0 g of ethyl p-[(E)-2-(4,4-dimethyl-6-chromanyl)propenyl]benzoate were dissolved in 50 ml of ether and the solution was treated slowly at 0° C. with 25.2 ml of a diisobutylaluminium hydride solution (20% in toluene). After stirring at 0° C. for 1 hour, 25 ml of methanol/water (1:1) were cautiously added dropwise thereto, the mixture was stirred at room temperature for 30 minutes and the precipitate was filtered off. The filtrate was dried, filtered over a short column of silica gel [eluting agent: hexane/ether (1:1)] and evaporated. After recrystallization from hexane/ether, there was obtained 2.9 g of p-[(E)-2-(3,4-dihydro-4,4-dimethyl-1-benzopyran-6-yl)propenyl]benzyl alcohol in the form of colorless crystals of melting point 80°-81° C.

Workup

stirringthe mixture was stirred at room temperature for 30 minutes
filtrationthe precipitate was filtered off
customThe filtrate was dried
filtrationfiltered over a short column of silica gel [eluting agent: hexane/ether (1:1)]
customevaporated
customAfter recrystallization from hexane/ether

Sources & evidence

ORD record: ord-0dd55635d6944fc8b42987d23c624af3
Source dataset: uspto-grants-1987_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04678793

Reaction notes

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