Ammonia → 3-Chloro-4-cyclohexylethynylbenzene

Beteiligte Stoffe

Reaktionsschritte

3-Chloro-4-cyclohexylacetophenone (0.25 moles) and phosphorus pentachloride (0.31 moles) are placed in a 3-necked flask equipped with a mechanical stirrer, a condenser connected to a nitrogen inlet, and a thermometer. The mixture is stirred at 33°-35° C. for 3 days. The cooled reaction mixture is poured onto 800 g. of ice and extracted with 3× 500 ml. of ether. The ether fraction is washed with 2× 100 ml water 4× 100 ml of 5% sodium hydroxide, 3× 50 ml water, 2× 50 ml of saturated saline and dried over sodium sulfate. The ether is removed to give the chlorinated intermediate. The intermediate is dissolved in anhydrous THF (200 ml) and is added dropwise to a freshly prepared solution of sodamide in liquid ammonia, using a dry-ice condenser. The reaction mixture is allowed to stir at room temperature overnight; then, it is poured into 50 ml of water and 500 ml of ether. The ether fraction is washed with 3× 50 ml water and 50 ml of saturated saline and is dried over sodium sulfate. Removal of solvent gives a residue which is distilled to give 3-chloro-4-cyclohexylethynylbenzene.

Herkunft & Nachweise