One-pot-one-step, microwave-assisted Fischer indole synthesis

摘要

The Fischer indole synthesis was carried out using microwaves instead of conventional heating procedures. When the mixture of phenylhydrazine, cyclohexanone and zinc chloride was irradiated at 600 W for 3 min, 76% of 1,2,3,4-tetrahydrocarbazole was obtained. However, when zinc chloride was replaced with p-toluenesulfonic acid (p-TSA), the reaction yielded 91% of 1,2,3,4-tetrahydrocarbazole. Thus, a series of indoles were prepared using microwaves in the presence of p-TSA catalyst.