Boron tribromide → 2-(1,3-Dioxo-1,3-dihydro-isoindol-2-ylmethyl)-4,5-dihydroxy-benzonitrile

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Reaction Conditions

Reaction Steps

2-(1,3-dioxo-1,3-dihydro-isoindol-2-ylmethyl)-4,5-dimethoxy-benzonitrile (20.36 g, 0.0632 mol) was dissolved in warm methylene chloride (253 mL) then cooled to 0° C. Boron tribromide (1 M in CH2Cl2, 253 mL, 0.2527 mol) was added dropwise over 45 min while maintaining the temperature under 5° C., under nitrogen. The resulting mixture was allowed to warm to room temperature with stirring under nitrogen for 23 h. The resulting mixture was then cooled to 0° C. and quenched by the dropwise addition of methanol (90 mL) over 45 min. The resulting mixture was concentrated in vacuo. The resulting precipitate was suspended in methanol (2×) and concentrated in vacuo. The resulting precipitate was taken up in boiling methanol (900 mL) and hot filtered. The filtrate was concentrated to about 200 mL and allowed to crystallize. The resulting precipitate was collected via filtration to yield the title compound-2-(1,3-dioxo-1,3-dihydro-isoindol-2-ylmethyl)-4,5-dihydroxy-benzonitrile—as a gray solid.

Provenance & Evidence