Water → 2,5-Diamino-4,6-dichloropyrimidine

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Reaction Steps

A mixture of 2-amino-4,6-dichloro-5-[(dimethylamino)methylene]amino}pyrimidine (Example 2, 500 mg, 2.14 mmol), pH 3.2 aqueous potassium phosphate buffer (1.5 M, 6 mL, prepared as described in Example 3), water (1 mL), and ethanol (5 mL) was refluxed gently for 28 hours. During the reflux period, pH was maintained at ca. 3 by addition of 85% phosphoric acid. Volatiles were evaporated in vacuo and the residual solids partitioned between water (30 mL, adjusted to ph 8 with dilute ammonium hydroxide) and chloroform (75 mL). The chloroform layer was dried (sodium sulfate) and the chloroform evaporated to leave off-white solid (0.30 g). Crystallization of this solid from ethanol:water/4:1 gave the title compound (IV) as light pink needles (332 mg, 61%); darkens and shrinks to black solid above 185° C., does not become fluid below 300° C.; 1H-NMR (DMSO-d6) and mass spa identical to those described in Example 4.

Provenance & Evidence