Hydrazine hydrate (1:1) → 1H-pyrazolo(3,4-b)pyridine

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Reaction Conditions

Reaction Steps

2-Chloro-3-pyridinecarboxyaldehyde (1.0 g, 7.0 mmol) and p-toluenesulfonic acid monohydrate (700 mg) were dissolved in hydrazine monohydrate (1.4 mL, 28.0 mmol). The resulting mixture was heated at 120° C. for 10 minutes in a sealed tube under irradiation with a macrowave of 100 watts. After cooled to room temperature, the mixture was neutralized with a saturated sodium bicarbonate aqueous solution and extracted with DCM (50 mL) three times. The organic layer was dried over anhydrous sodium sulfate. The concentrated residue was purified by silica gel (Fuji Silysia, BW300, 30 g, n-hexane:ethyl acetate=1:1) to give 1H-pyrazolo[3,4-b]pyridine (513 mg, yield: 62%).

Provenance & Evidence