A solution of phenylmagnesium bromide is prepared in a 2-l. three-necked flask, fitted with a separatory funnel, reflux condenser, and a mercury-sealed stirrer, from 8.8 g. (0.36 gram atom) of magnesium, 56.5 g. (38 ml., 0.36 mole) of bromobenzene, and a total of 350 ml. of dry ether by the procedure described in Org. Syntheses Coll. Vol. 1, 226 (1941).

To the solution of the Grignard reagent, cooled by an ice-salt bath, a mixture of 21.3 g. (0.3 mole) of methoxyacetonitrile [Org. Syntheses Coll. Vol. 2, 387 (1943)] and 50 ml. of dry ether is slowly added with stirring. The colorless addition product separates at once. After standing at room temperature for 2 hours, the mixture is again cooled and then decomposed by adding, with stirring, 500 ml. of water and cracked ice, and then 100 ml. of cold dilute sulfuric acid (Note 1). When the decomposition is complete (Note 2), the ether layer is separated and the aqueous layer is extracted with a little ether. This ether extract is combined with the ether layer, and the whole is washed with 5% aqueous sodium carbonate solution and then with water. The solution is dried with anhydrous sodium sulfate.

The ether is removed by distillation from a steam bath, and the residue is distilled under diminished pressure. ω-Methoxyacetophenone is a colorless liquid which boils at 118–120° /15 mm. or 228–230° /760 mm. (Note 3). The yield is 32–35 g. (71–78% based on the methoxyacetonitrile).