Phosgene → Ethyl 3-(chloroformyl)carbazate

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Reaction Steps

Phosgene (100 ml, 1.41 mole) was condensed into a 2 l flask and anhydrous diethyl ether (160 ml) was added. The solution was kept at 0° C. in an ice bath and ethyl carbazate (103 g, 1 mole) in anhydrous diethyl ether (800 ml) was added dropwise over a period of 3 hr to the stirred phosgene solution. Stirring was continued for 1 hr after the end of the addition and ether and excess phosgene were removed by distillation. The crude solid product was re-dissolved in warm anhydrous ether (800 ml) and filtered in a dry atmosphere to remove insoluble by-products. Evaporation of the filtrate gave 2-ethoxycarbonylhydrazinecarbonyl chloride (150 g, 90%) m.p. 78°-80° C. Recrystallisation of a sample from a mixture of anhydrous diethyl ether and petroleum ether (1:2.5) gave a colourless crystalline solid mp 82°-6° C. (Lit 78°-80° C.). The ir spectrum of the product was in agreement with the published spectrum.

Provenance & Evidence