4-Aminophenol → Ethyl 7-(4-Hydroxyanilino)-1H-pyrazolo[4,3-b]pyridine-6-carboxylate

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Reaction Steps

Ethyl 7-chloro-1H pyrazolo[4,3-b]pyridine-6-carboxylate (1.0 g, 0.004 mole) and p-aminophenol (1.0 g, 0.009 mole) were stirred together in ethyl acetate (200 ml) under nitrogen for 48 hours, the temperature being maintained between -10° and -5° C. The ethyl acetate was removed under reduced pressure to give a yellow solid. This solid was dissolved in aqueous ethanol and the pH adjusted to pH8 with 10% sodium carbonate solution. The resulting solid was filtered off washed with water and dried. Recrystallization from methanol/ethyl acetate gave the title compound as a pale yellow solid (650 mg, 50%), m.p. 286°-287° C. (decomposition)

Provenance & Evidence