THE SYNTHESIS OF SOME MANNICH REACTION PRODUCTS OF INDOLE WITH FURFURAL UNDER SOLVENT-FREE CONDITIONS D.G. Urmonov, I.J. Jalolov, A.A. Ibragimov Department of Chemistry, Fergana State University 19, Murabbiylar street, Fergana, Uzbekistan Indole and furan moieties are the significant structural units for various biologically
important compounds.
These compounds are widely employed as antibacterial,
antiviral, anti-inflammatory, anti-fungal, anti-tumor, anti-hyperglycemic, analgesic,
anti-convulsant, etc. Meanwhile,
Mannich reaction is a key step in synthesis of a wide
variety of natural products, pharmaceuticals and important for the construction of
nitrogen containing compounds. The Mannich reaction of indoles give gramines which
have been recently found as novel agents against certain types of plant virus. Here is
shown the simple synthesis of compounds bearing both indole and furan moieties
employing Mannich reaction under the solvent-free condition.
The general method:
Furfural (0.05 mol) and appropriate cyclic or aromatic amines
(0.05 mol) were placed in a dried round-bottomed flask containing a magnetic stirrer bar
and equipped with a reflux condenser. The mixture was stirred at 50−80 °C for about 3-
5 hours. Then indole (0.5 mol) was added in small parts for 15-20 minutes, and the
mixture was heated. The reaction procedure was monitored by thin-layer
chromatography (TLC). After completion, the reaction mixture was cooled to room
temperature. The solution was poured into ice-water, and the precipitate was filtered off.
Compounds below were purified by chromatography on a column of silica gel with
Hexane-EtOAc (v/v = 2:1). The yields were 30-50%.