Chromanone → Benzopyran

Beteiligte Stoffe

Reaktionsschritte

The chromanone was dissolved in 400 ml. of dry ethyl ether, and 2.5 gm of lithium aluminum hydride was added in portions. The reaction was refluxed for 2 hours and then allowed to come to room temperature. The excess lithium aluminum hydride was destroyed by dropwise addition of water and 150 ml. of 4N HCl was added slowly to the reaction mixture. Stirring was continued for 15 minutes. The reaction mixture was extracted with ether and washed successively with 100 ml. of water, 100 ml. 5% sodium carbonate solution and 100 ml. saturated NaCl solution. The ethereal extract was dried over anhydrous sodium sulfate. Removal of the ether in vacuo gave 15.6 g of crude chromene.

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