New 3H-indole synthesis by Fischer's method. Part I

Molecules. 2010 Apr 8;15(4):2491-8. doi: 10.3390/molecules15042491.

Abstract

Methyl indolenines (4a-c) and(5a-c) were prepared in high yield by a Fischer indole synthesis reaction of o,m-tolylhydrazine hydrochlorides (1a-b) with isopropyl methyl ketone (2) and 2-methylcyclohexanone (3) in acetic acid at room temperature. o,p- Nitrophenylhydrazines (1c-d) were reacted with 2-methylcyclohexanone (3) in acetic acid at reflux to give nitroindolenines (5d-e), while the attempted reactions of o,p-nitrohydrazines with isopropyl methyl ketone (2) in acetic acid were not successful. Compounds(1c-d) were reacted with isopropyl methyl ketone (2) in acetic acid/HCl to give 2,3,3-trimethyl-5-nitro-indolenine (4e) and 2,3,3-trimethyl-7-nitroindolenine (4d).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetic Acid / chemistry
  • Cyclohexanones / chemistry
  • Hydrazines / chemistry
  • Indoles / chemical synthesis*
  • Pentanones / chemistry

Substances

  • Cyclohexanones
  • Hydrazines
  • Indoles
  • Pentanones
  • 2-methylcyclohexanone
  • Acetic Acid
  • isopropyl methyl ketone