Aluminum(III) Chloride → 4,4-Dimethyl-3,4-dihydroquinolin-2(1H)-one

Participants

Reaction Conditions

Reaction Steps

To 40 g (0.22 mol) of 3-methylcrotonoanilide, heated in the molten state at 130° C., was added 33.4 g (0.25 mol) of aluminum chloride, portionwise, over a 30 minute period. Heating was continued at 130° C. for a further 30 minutes, and then the temperature was lowered to 85° C. and a further 5 g (0.038 mol) of aluminum chloride was added. The temperature was maintained at 85° C. for 1 hour and then the reaction mixture was treated cautiously with 500 g of ice. The resulting mixture was extracted with ether and the ether extracts were dried (MgSO4) and evaporated in vacuo. The residue was chromatographed on silicic acid, eluting with ether:hexane (1:2), and the product containing fractions were combined and evaporated in vacuo. This afforded 23.7 g (59% yield) of the title compound, mp 111°-112° C.

Provenance & Evidence