3-Methylindole and indole prodn - by cyclisation of 2-(o-aminophenyl)-1,3-propanediol on a catalyst contg. chromium and copper

摘要

Indole and 3-methylindole are prepd. by cyclisation of 2-(o-aminophenyl)-1,3-propanediol (I) in the presence of H and H2O on a SiO2-based catalyst contg. CrO2, CuO and BaCrO4 at 220-350 degrees, pref. 250-300 degrees, contact time being 1-20, pref. 3-10 secs. The prod. is 3-methylindole with ca. 20% indole, which are sepd. by fractional distillation; a higher proportion of indole is obtd. by introducing pyridine (2-5, pref. 3 moles per mole of I) to the reaction mixt.