Ammonium Hydroxide → 1-ethyl-4-chloro-6,7-dimethoxy-1H-pyrazolo[3,4-b]quinoline

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Reaction Steps

A mixture of N-(1-ethylpyrazol-5-yl)-4,5-dimethoxy anthranilic acid (12.8 g, 44 mmol) and POCl3 (75 ml) is refluxed for 8 hours. The reaction mixture is cooled to room temperature, poured into ice water and neutralized with concentrated NH4OH. The mixture is extracted with CH2Cl2, and the CH2Cl2 layer is dried over MgSO4 and evaporated to dryness. The residue is purified by column chromatography on silica gel eluting with CH2Cl2 /ether (9/1) to afford 8.0 g (62%) of 1-ethyl-4-chloro-6,7-dimethoxy-1H-pyrazolo[3,4-b]quinoline.

Provenance & Evidence