4-Toluenesulfonyl chloride → 9-Fluoro-6-(p-toluenesulfonyloxy)benzo[g]isoquinoline-5,10-dione

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Reaction Steps

Triethylamine (8.20 mL) is added to a stirred suspension of the 9/1 mixture of 9-fluoro-6-hydroxybenzo[g]isoquinoline-5,10-dione and 9-chloro-6-hydroxybenzo[g]isoquinoline-5,10-dione respectively of Preparative Example 9b (5.53 g) and p-toluenesulfonylchloride (8.47 mL) in methylene chloride (166 mL). The reddish-violet solution obtained is left at room temperature under a nitrogen atmosphere for 1 hour and then it is poured into water (500 mL). The organic phase is separated and the aqueous solution is further extracted with methylene chloride (100 mL). The combined organic solutions are dried (Na2SO4) and concentrated to dryness. The obtained solid is suspended in n-hexane (100 mL) for 1 hour and filtered to give a 9:1 mixture (1H-NMR evaluation) of 9-fluoro-6-(p-toluenesulfonyloxy)benzo [g]isoquinoline-5,10-dione and 9-chloro-6-(p-toluenesulfonyloxy)benzo[g]isoquinoline-5,10-dione respectively (8.85 g).

Provenance & Evidence