Methylhydrazine → 5-chloro-2-methylisoquino[5,6,7-cd]indazole-6(2H)-one

Participants

Reaction Steps

A solution of methyl hydrazine (0.76M; 0.021 g) in pyridine (0.6 mL) is added dropwise over two min to a stirred solution of 9-chloro-6-fluorobenzo[g]isoquinoline-5,10-dione of Preparative Example 13 in pyridine (0.5 mL) cooled with an ice-bath. A yellow precipitate appears in the dark solution after 6 min. After 1.3 h the reaction mixture is reduced to half its volume by a gentle stream of nitrogen and quenched with ice (5 g). The pale yellow precipitate is collected by suction filtration and washed with ice-water (2×1 mL) and dried under vacuum. The yellow solid is purified by silica gel column chromatography (eluant: chloroform/methanol 96/4 v/v) to yield 5-chloro-2-methylisoquino[5,6,7-cd]indazole-6(2H)-one (0.033 g; 71% yield) as a yellow solid.

Provenance & Evidence