Sulfuric Acid → 4-(2',4'-Dichloro-4-ethylbiphenyl-3-yl)-2,2,6,6-tetramethylpyran-3,5-dione

HRID 879085Notes

Reaction equation

S(=O)(=O)(O)O.[Cl:6][C:7]1[CH:12]=[C:11]([Cl:13])[CH:10]=[CH:9][C:8]=1[C:14]1[CH:19]=[CH:18][C:17]([CH2:20][CH3:21])=[C:16]([CH:22]2[C:24]3([C:28](=[O:29])[C:27]([CH3:31])([CH3:30])[O:26][C:25]3([CH3:33])[CH3:32])[O:23]2)[CH:15]=1>ClCCCl>[Cl:6][C:7]1[CH:12]=[C:11]([Cl:13])[CH:10]=[CH:9][C:8]=1[C:14]1[CH:19]=[CH:18][C:17]([CH2:20][CH3:21])=[C:16]([CH:22]2[C:28](=[O:29])[C:27]([CH3:31])([CH3:30])[O:26][C:25]([CH3:33])([CH3:32])[C:24]2=[O:23])[CH:15]=1

Participants

Conditions

Temperature: 0 °C

Procedure

To an ice-cold solution of concentrated sulphuric acid (6 ml) is added a second solution of 2-(2′,4′-dichloro-4-ethylbiphenyl-3-yl)-4,4,6,6-tetramethyl-1,5-dioxaspiro[2.4]heptan-7-one (1.90 g, 0.0045 mol) in 1,2-dichloroethane (6 ml) dropwise over 5 mins. This biphasic mixture is stirred vigorously for 2 hours at 0° C., then is poured into ice and extracted with diethyl ether. All organics are combined, washed with brine, dried over magnesium sulfate then concentrated in vacuo. The crude product is purified by flash column chromatography (5% ethyl acetate in isohexane to 25% ethyl acetate in isohexane) to afford 4-(2′,4′-dichloro-4-ethylbiphenyl-3-yl)-2,2,6,6-tetramethylpyran-3,5-dione as a yellow gum.

Workup

additionis poured into ice
extractionextracted with diethyl ether
washwashed with brine
dry with materialdried over magnesium sulfate
concentrationthen concentrated in vacuo
customThe crude product is purified by flash column chromatography (5% ethyl acetate in isohexane to 25% ethyl acetate in isohexane)

Sources & evidence

ORD record: ord-7db0236c5aaf45c09753ce53275fc23e
Source dataset: uspto-grants-2015_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08987476B2

Reaction notes

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