Nitrourea with hydrazines

Salts of semicarbazide have been prepared by the action of potassium cyanate on hydrazine sulfate 1 by the action of hydrazine hydrate on urea 2 by heating hydrazine ammonium carbonate 3 bv the reduction of nitrourea with zinc dust and hydrover. 27, 31 (1894). 

Semicarbazide (Aminourea, Carbamylhydrazine or Hydrazine carboxamide). NHi.NH.CO.NHj mw 75.07 colorl prisms mp 96° d l,484g/cc at 4°. V sol in w sol in ethanol. Prepn is by electrolytic redn of nitrourea in sulfuric acid. The base Is then obtd by reaction of the semicarbazide sulfate with liq ammonia. CA Registry No [57-56-7]. See also in Vol 2, C45-L, under Carbazide for a definition of semicarbazide Semicarbazide forms salts which are either expl or, as in the case of the hydrochloride, are used in propint compns... 

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