3-Amino-2-pyrazinecarboxylic acid → 3-(1-ethyl-1H-imidazo[4,5-c]pyridin-2-yl)pyrazin-2-amine

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Reaction Conditions

Reaction Steps

To polyphosphoric acid, preheated to 130° C., was added in one portion an intimate mixture of the product of Example 1 Step 2 (206 mg, 1.5 mmol) and 3-aminopyrazine-2-carboxylic acid (230 mg, 1.65 mmol). The temperature was increased to 195° C. for 1 hour and then cooled back to 130° C. for a further 1 hour. The viscous oil was poured on to ice containing saturated sodium carbonate solution and diethyl ether (5 ml) and the aqueous solution was extracted with chloroform (×5). The combined organic extracts were washed with brine, dried over anhydrous magnesium sulfate and concentrated in vacuo. The crude solid was purified by silica gel chromatography eluting with a gradient of dichloromethane to 0.880 ammonia:ethanol:dichloromethane (1:9:40), to afford the title compound, (20 mg, 6%); MS (ES+) m/e 241 [M+H]+.

Provenance & Evidence