Triuret

Triuret is an organic compound with the formula (H2NC(O)NH)2CO. It is a product from the pyrolysis of urea. Triuret is a colorless, crystalline, hygroscopic solid, slightly soluble in cold water or ether, and more soluble in hot water. It is a planar molecule. The central carbonyl is hydrogen-bonded to both terminal amino groups.

Synthesis
The compound is typically prepared by heating thin layers of urea, the thin layers facilitating escape of ammonia:
 * 3 (H2N)2CO  →   [H2NC(O)NH]2CO  +  2 NH3

It can also prepared by treatment of urea with phosgene:
 * 2 (H2N)2CO +  COCl2  →   [H2NC(O)NH]2CO  +  2 HCl

A similar synthesis employs urea and dimethyl carbonate with potassium methoxide as a catalyst:
 * 2 (H2N)2CO +  CO(OCH3)2  →   [H2NC(O)NH]2CO  +  2 MeOH

The original synthesis entailed oxidation of uric acid with hydrogen peroxide.

Triuret is a complicating by-product in the industrial synthesis of melamine from urea.

Related compounds

 * Urea
 * Biuret
 * Cyanuric acid