conditions are sufficient for producing batches of 100 kg or more. Variations and related reactions One of the most common variations of the Nenitzescu reaction is the solid phase variant. This reaction, first reported by Ketcha et al., is shown below. It takes place on a highly cross-linked ArgoPore®-Rink-NH-Fmoc resin and functions with a variety of substituents on both reactants. Other solid-phase indole syntheses were also reported, some of which use different scaffolds and metal catalysts to drive the reaction to completion. There are also a variety of other reactions that result in the same indole skeleton. In a review article, Taber et al. categorize these reactions into nine basic types of indole syntheses: Fischer, Mori, Hemetsberger, Buchwald, Sundberg, Madelung, Nenitzescu, van Leusen and Kanematsu. Applications The 5-hydroxyindole skeleton is the foundation for a number of biochemically important molecules. Among them are serotonin, a neurotransmitter; indometacin, a non-steroidal anti-inflammatory agent; L-761,066, a COX-2 inhibitor; and LY311727, an inhibitor of secretory phospholipase. Currently, one of the most interesting applications of the Nenitzescu synthesis is its ability to produce a precursor to antitumor compounds. This synthesis, reported in 2006, involves the reaction of 1,4,9,10-anthradiquinone with various enamines. The products of this reaction constitute a new class of lead structures for anticancer drug design. References Indole forming reactions Carbon-heteroatom bond forming reactions Name reactions