5-(2'-Hydroxy-3',4',6'-trimethylbenzoyl)pentanoic acid → 6-Hydroxy-6-(2'-hydroxy-3',4',6'-trimethylphenyl)hexanoic acid

HRID 1248599Notes

Reaction equation

[H-].[Al+3].[Li+].[H-].[H-].[H-].[OH:7][C:8]1[C:22]([CH3:23])=[C:21]([CH3:24])[CH:20]=[C:19]([CH3:25])[C:9]=1[C:10]([CH2:12][CH2:13][CH2:14][CH2:15][C:16]([OH:18])=[O:17])=[O:11]>O1CCCC1>[OH:11][CH:10]([C:9]1[C:19]([CH3:25])=[CH:20][C:21]([CH3:24])=[C:22]([CH3:23])[C:8]=1[OH:7])[CH2:12][CH2:13][CH2:14][CH2:15][C:16]([OH:18])=[O:17]

Participants

Conditions

Temperature: 0 °C

Procedure

To a well stirred suspension of lithium aluminum hydride (2 parts) in dry tetrahydrofuran (50 volume parts) was added a solution of 5-(2'-hydroxy-3',4',6'-trimethylbenzoyl)pentanoic acid (formula II-1 wherein R=H3C, X=H, Y=OH, n=4, in the free form) in dry tetrahydrofuran (10 volume parts) at room temperature. After being stirred under reflux for 2 hours, the mixture was cooled to 0° C., acidified with cold dilute hydrochlororic acid, and extracted with ethyl acetate. The ethyl acetate extract was washed with water, dried over anhydrous sodium sulfate, and concentrated in vacuo. The resulting residue was subjected to column chromatography on silica gel and eluted with carbon tetrachloride-acetone (5:1). From the 1st fraction, 6-hydroxy-6-(2'-hydroxy-3',4',6'-trimethylphenyl)hexanoic acid (formula II-3 wherein R=H3C, X=H, Y=OH, n=4, in the free form) (0.45 part) was obtained as colorless needles melting at 165°-166° C.

Workup

customat room temperature
stirringAfter being stirred
temperatureunder reflux for 2 hours
extractionextracted with ethyl acetate
extractionThe ethyl acetate extract
washwas washed with water
dry with materialdried over anhydrous sodium sulfate
concentrationconcentrated in vacuo
washeluted with carbon tetrachloride-acetone (5:1)

Sources & evidence

ORD record: ord-9e4dcff56fac4062a6c96cd093660417
Source dataset: uspto-grants-1985_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04525361

Reaction notes

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