A-BROMOCINNAMIC ALDEHYDE ACETAL

B. a-Bromocinnamic aldehyde acetal. In a 250-ml. flask are placed 45 g. (0.21 mole) of a-bromocinnamic aldehyde, 50 ml. 

C. Phenylpropargyl aldehyde acetal. A solution of 20.7 g. (0.25 mole) of potassium hydroxide in 200 ml. of absolute ethanol is added to 50 g. (0.18 mole) of a-bromocinnamic aldehyde acetal in a 500-ml. flask. The mixture is refluxed for 1.5 hours and poured into a 3-1. separatory funnel containing 1.5 1. of water. The oil which separates is extracted with three 170-ml. portions of chloroform, and the combined chloroform extracts are washed with three 75-ml. portions of water and then dried over 15 g. of anhydrous sodium sulfate. The chloroform is removed by distillation, and the residual oil is distilled from a modified Claisen flask. The yield of phenylpropargyl aldehyde acetal boiling at 153-156°/19 mm. is 28-31 g. (80-86%). 

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