Hydrazine → 4-chloro-6-methyl-1H-pyrazolo[3,4-d]pyrimidine

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Reaction Steps

The resulting solution of 4,6-dichloro-2-methylpyrimidine-5-carbaldehyde was treated dropwise with a solution of anhydrous hydrazine (1101 μL, 35071 μmol) at −78° C. The mixture was stirred for 15 min, and then the cooling bath was removed and the mixture stirred at RT for 1 h. The mixture was concentrated and partitioned between water (110 mL) and EtOAc (110 mL). The organic layer was washed with saturated aqueous NaHCO3 (100 mL), separated, dried (MgSO4), treated with activated charcoal and filtered through a plug of silica, washing with EtOAc. The filtrate was concentrated and purified by flash chromatography on silica eluting with 5% acetone/DCM to 25% EtOAc/hexane. The residue was suspended in DCM (3 mL), cooled in a freezer, and filtered to give 4-chloro-6-methyl-1H-pyrazolo[3,4-d]pyrimidine (330 mg, 5.86% yield) as a tan solid. 1H NMR (400 MHz, d6-DMSO) δ 14.25 (bs, 1H); 8.35 (s, 1H); 2.68 (s, 3H).

Provenance & Evidence