Acetyl chloride → 1-(3,4-dihydro-2H-1-benzopyran-6-yl)ethan-1-one

HRID 591074Notes

Reaction equation

[Cl-].[Al+3].[Cl-].[Cl-].[C:5](Cl)(=[O:7])[CH3:6].[O:9]1[C:14]2[CH:15]=[CH:16][CH:17]=[CH:18][C:13]=2[CH2:12][CH2:11][CH2:10]1>ClCCl>[O:9]1[C:14]2[CH:15]=[CH:16][C:17]([C:5](=[O:7])[CH3:6])=[CH:18][C:13]=2[CH2:12][CH2:11][CH2:10]1

Participants

Conditions

Temperature: -10 °C

Procedure

Aluminium chloride (1.19 g, 8.9 mmol) was added portionwise to a stirred solution of acetyl chloride (1.21 mL, 17.0 mmol) in dry dichloromethane (20 mL), previously cooled to −10° C., until homogeneous (5 min). The solution was added, via cannula, to a solution of 3,4-dihydro-2H-1-benzopyran (9a) (1.20 g, 8.9 mmol) in dry dichloromethane (17 mL) at −10° C. The mixture was stirred at the same temperature for 30 minutes before being poured into ice/concentrated hydrochloric acid (5:1, v/v, 126 mL). The stirring was maintained at room temperature for 2 hours and the solution was extracted with dichloromethane (3×50 mL). The organic layer was dried over sodium sulfate and concentrated in vacuo to provide 1-(3,4-dihydro-2H-1-benzopyran-6-yl)ethan-1-one (49a) (1.55 g, 8.8 mmol, 99%) which was used without further purification.

Workup

temperatureThe stirring was maintained at room temperature for 2 hours
extractionthe solution was extracted with dichloromethane (3×50 mL)
dry with materialThe organic layer was dried over sodium sulfate
concentrationconcentrated in vacuo

Sources & evidence

ORD record: ord-4d852f4a432746b2936bff5bfc71437a
Source dataset: uspto-grants-2016_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09238026B2

Reaction notes

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