Hydrochloric Acid → 3,4-dihydro-6-methoxy-2-[2-(p-toluenesulfonyloxy)ethyl]-2,5,7,8-tetramethyl-2H-benzopyran

HRID 568726Notes

Reaction equation

[OH:1][CH2:2][CH2:3][C:4]1([CH3:19])[CH2:9][CH2:8][C:7]2[C:10]([CH3:18])=[C:11]([O:16][CH3:17])[C:12]([CH3:15])=[C:13]([CH3:14])[C:6]=2[O:5]1.[C:20]1([CH3:30])[CH:25]=[CH:24][C:23]([S:26](Cl)(=[O:28])=[O:27])=[CH:22][CH:21]=1.Cl>N1C=CC=CC=1>[CH3:17][O:16][C:11]1[C:12]([CH3:15])=[C:13]([CH3:14])[C:6]2[O:5][C:4]([CH2:3][CH2:2][O:1][S:26]([C:23]3[CH:24]=[CH:25][C:20]([CH3:30])=[CH:21][CH:22]=3)(=[O:28])=[O:27])([CH3:19])[CH2:9][CH2:8][C:7]=2[C:10]=1[CH3:18]

Participants

Conditions

Temperature: 0 °C

Procedure

Pyridine (150 ml) was added to 40 g (160 mmol) of 3,4-dihydro-2-(2-hydroxyethyl)-6-methoxy-2,5,7,8-tetramethyl-2H-benzopyran for dissolution of the latter. Then the solution was cooled to 0° C. and thereto was added with vigorous stirring 34.5 g of p-toluenesulfonyl chloride gradually. After stirring at 0° C. for 1 hour, the reaction mixture was poured into 1 liter of dilute hydrochloric acid and extracted with diethyl ether. The ether layer was washed with water, dried over anhydrous magnesium sulfate and filtered. After removal of low-boiling substances from the filtrate by distillation, the residue was purified by silica gel column chromatography to give 49.8 g (78.6% yield) of 3,4-dihydro-6-methoxy-2-[2-(p-toluenesulfonyloxy)ethyl]-2,5,7,8-tetramethyl-2H-benzopyran, which has the following FD mass spectrum.

Workup

additionwas added
extractionextracted with diethyl ether
washThe ether layer was washed with water
dry with materialdried over anhydrous magnesium sulfate
filtrationfiltered
customAfter removal of low-boiling substances from the filtrate
distillationby distillation
customthe residue was purified by silica gel column chromatography

Sources & evidence

ORD record: ord-8f2f1921c8bd49a7a0872afea9eef11f
Source dataset: uspto-grants-1988_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04728650

Reaction notes

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