Preparation of Ethyl Diazoacetate
Typical Procedure: A solution containing 140 g glycine ethyl ester hydrochloride (1 mol) in 250 mL water is placed in a 2 L four neck flask. 600 mL dichloromethane is added and the mixture is cooled to -5 ℃ under a nitrogen atmosphere. A solution containing 83 g sodium nitrite in 250 mL water is cooled to 0 ℃ and added with stirring to the reaction mixture. While keeping the reaction temperature below -9 ℃, 95 g 5% sulfuric acid is added dropwise to the reaction over a 3 minute period. After ten minutes addition stirring the reaction is transferred to a 2 L separatory funnel while cold. The isolated yellow-greenish organic phase is poured into a cooled 1 L 5% sodium carbonate solution, then placed into a separatory funnel and shaken. The isolated aqueous phase is extracted with 75 mL dichloromethane, dried over 15 g anhydrous sodium sulfate, and concentrated under reduced pressure (350 mmHg). Further concentration at 20 mmHg and a bath temperature of 35 ℃ gives 90~100 g (79~88%) yellow oily substance. The product is pure enough to be used for ordinary synthesizing purposes. It is explosive, and distillation under even reduced pressure is hazardous. *Ethyl diazoacetate is explosive and very toxic. Wear protective gloves, protective goggles, protective mask, and use a safety screen. Work in a well ventilated fume hood.
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Org. Synth. 1963, Coll. Vol. 4, 424.
