The Reactions of a-Bromo Ketones with Primary Amines

Materials.-Acetone (Hopkin and Williams, AnalaR grade) was refluxed over anhydrous potassium carbonate for 6 hr. and then fractionated. The distillate waa then refluxed over phosphoric oxide for 6 hr. and then fractionated, the fraction boiling at 56.0-56.5" being collected in a flask protected from atmospheric moisture by phosphoric oxide and calcium chloride guard tubes. Dioxane and nit,robenzene were purified using the methods described by Vogel.13 Benzene ( AnalaR grade) was refluxed over sodium and then fractionated. Nitromethane was dried over anhydrous magnesium sulfate and fractionated, Amines %ere dried over potassium hydroxide pellets, decanted from the solid and distilled from fresh potassium hydroxide pellets. Ethyl methylphosphonochloridate was prepared as described elsewhere .4 Determination of Reaction Rates.-A large, well insulated dewar vessel, containing water or aqueous acetone cooled with solid carbon dioxide was used as a constant temperature bath. The temperature was maintained within f 0 . 1 " for a t least 0.5 hr. The solution of the amine in the solvent was placed in a stoppered flask and precooled to the desired reaction temperature by placing the flask in the constant temperature bath. Reaction was started by introducing the phosphonochloridate