Allyl bromide → racemic-3,4-dihydro-2,5,7,8-tetramethyl-6-(2-propenyloxy)-2H-1-benzopyran-2-acetic acid methyl ester

HRID 2231900Notes

Reaction equation

HRID 2231900 reaction equation
[CH3:1][O:2][C:3](=[O:20])[CH2:4][C:5]1([CH3:19])[CH2:10][CH2:9][C:8]2[C:11]([CH3:18])=[C:12]([OH:17])[C:13]([CH3:16])=[C:14]([CH3:15])[C:7]=2[O:6]1.[CH2:21](Br)[CH:22]=[CH2:23].[H-].[Na+]>CN(C)C=O>[CH3:1][O:2][C:3](=[O:20])[CH2:4][C:5]1([CH3:19])[CH2:10][CH2:9][C:8]2[C:11]([CH3:18])=[C:12]([O:17][CH2:23][CH:22]=[CH2:21])[C:13]([CH3:16])=[C:14]([CH3:15])[C:7]=2[O:6]1

Participants

5

Reactant 3

HCID 7841Allyl bromideHCID 24758Sodium hydrideHCID 13909413Methyl 6-hydroxy-2,5,7,8-tetramethylchroman-2-acetate

Product 1

HCID 54012058racemic-3,4-dihydro-2,5,7,8-tetramethyl-6-(2-propenyloxy)-2H-1-benzopyran-2-acetic acid methyl esterYield 83.1%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

Using the procedure of Example 12, 1.42 g of racemic-3,4-dihydro-2,5,7,8-tetramethyl-6-hydroxy-2H-1-benzopyran-2-acetic acid methyl ester was alkylated with allyl bromide (2.79 g) and sodium hydride (5.58 mmole) in anhydrous N,N-dimethylformamide. There was obtained 1.35 g (83.1%) of racemic-3,4-dihydro-2,5,7,8-tetramethyl-6-(2-propenyloxy)-2H-1-benzopyran-2-acetic acid methyl ester as a yellow oil, after column chromatographic purification (silica gel, 9:1 hexane-ethyl acetate).

Sources & evidence

ORD record
ord-e9ac66453ea04299a646f3774a832c3d
Source dataset
uspto-grants-1988_11
Patent number
US04785017

Reaction notes

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