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To a mixture of water (100 ml) and acetone (15 ml), sodium salt of 2-hydroxyimino-2-cyanoacetic acid amide (19.6 g) is added, and the obtained solution in which a part of the sodium salt is present in a suspended state is cooled at 0°C. Ethyl chloroformate (15 g) is dropwise added thereto, and the resulting mixture is, after adjusted to pH 7 to 8 with the addition of an aqueous solution of sodium hydrogencarbonate, stirred at room temperature for 1 hour and then filtered to collect the precipitated crystals. To the filtrate, a small amount of acetonitrile is added, and the mixture is extracted with ether. The ether layer is washed with water, dried and concentrated to give crystals, which are put together with the above obtained crystals to obtain 2-ethoxycarbonyloxyimino-2-cyanoacetic acid amide (22.5 g). A part of the product is recrystallized from ethyl acetate to give crystals melting at 194° to 196°C.

1. additionis added
2. filtrationfiltered
3. customto collect the precipitated crystals
4. additionTo the filtrate, a small amount of acetonitrile is added
5. extractionthe mixture is extracted with ether
6. washThe ether layer is washed with water
7. customdried
8. concentrationconcentrated
9. customto give crystals, which
10. customabove obtained crystals