2,2-diethyl-3,4-dihydro-4-oxo-2H-1-benzopyran-6-carbonitrile → 2,2-Diethyl-2h-chromene-6-carbonitrile

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Reaction Steps

13,7 g of this 4-chromanone are dissolved in 420 ml ethanol and the obtained solution is mixed with 1,14 g of sodiumborhydride. After 5 hours at room temperature the reaction solution is partitioned between water and dichloromethane, the organic phases are dried over sodiumsulphate and concentrated. 15 g of the obtained residue are taken up in 600 ml of toluene and are refluxed for 5 hours together with 570 mg of p-toluene-sulphonic acid in a Dean Stark apparatus. Washing of the reaction solution with 2N aq. sodium hydroxide solution and water yields after drying over sodiumsulphate and concentration a residue that is purified by flash-chromatography (silica gel/dichloromethane, hexane 1:2). Concentration of the eluate gives 2,2-diethyl-1-benzopyran-6-carbonitrile as colorless oil.

Provenance & Evidence