p-Toluenesulfonic acid → 7-trifluoromethyl-10H-benzo(4,5)furo(3,2-b)indole-1-carboxylic acid

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Reaction Steps

150 mg 6a was dissolved in ethanol (5.2 ml) and 2-hydrazino benzoic acid was dissolved in water (10.3 ml). These two homogenous mixtures were mixed together and stirred at room temperature for 4 hrs. Precipitation is filtered and first washed with water and then ethanol. The filtrate was put in vacuum oven for 4 hrs for complete evaporation. The mixture of 2-[N′-(6-trifluoromethyl-benzofuran-3-yl-idene)-hydrazino]-benzoic acid (120 mg), p-TsOH (1˜2 Eqv) and ethanol (5 ml) were refluxed for 30 hrs. Cooled to room temperature and evaporated in vacuo. Resulting mixture was purified by chromatography to afford compound 8 (CHCl3:MeOH=30:1).

Provenance & Evidence