2,4-Diaminopyrimidine → 5-Bromopyrimidine-2,4-diamine

Participants

Reaction Conditions

Reaction Steps

To a mixture of 2,4-diaminopyrimidine (5.5 g, 0.05 mol, 1.0 eq.) and THF (200 ml) was added pyridinium tribromide (17.5 g, 0.055 mol, 1.1 eq) at 0° C. in three portions. The resulting mixture was stirred at about 0° C. for two hours, filtered and washed with THF (20 ml). The yellow solid was mixed with water (100 ml) and the resulting mixture was neutralized with 10% NaOH solution to a pH of about 7. Stirring was continued at room temperature for 30 minutes, after which the mixture was filtered, washed with water (2×20 ml) and dried under vacuum at 50° C. to give 8.2 g (87%) of 2,4-diamino-5-bromo-pyrimidine as a white solid. 1H NMR, HPLC and LCMS analyses of this product are identical to the product described in Step 1 of Example 1.

Provenance & Evidence