Ammeline

Ammeline (4,6-Diamino-2-hydroxy-1,3,5-triazine) is a triazine. It is the hydrolysis product of melamine.

Synthesis
Ammeline can be synthesized by the pyrolysis of urea, or the condensation reaction amond 2 moles of dicyandiamide with 1 mole of biuret.
 * 2C2H4N4 + C2H5N3O2 → 2C3H5N5O + NH3

Chemical property
Ammeline is weakly acidic with pKa ~9. It can form nitrate, sulfate, chromate and oxalate salts. Ammeline reacts with boiling dilute hydrochloric acid to form melem and ammonia.

Ammeline is the first step in melamine hydrolysis. Further hydrolysis (e.g. boiling ammeline with dilute alkali) yields ammelide.