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Article Abstract
The synthesis of 2,3,5-trisubstituted 7-azaindoles as well as 2,5-disubstituted 7-azaindoles from 3,5-dihalogenated 2-aminopyridines is outlined. Using a double Sonogashira coupling reaction on 2-amino-3,5-diiodopyridine followed by the Cacchi reaction the synthesis of 2,3,5-trisubstituted 7-azaindoles was accomplished. In addition, using two sequential Sonogashira coupling reactions on 2-amino-5-bromo-3-iodopyridine and a potassium t-butoxide mediated ring closure reaction resulted in the assembly of 2,5-disubstituted 7-azaindoles. The 5-alkynyl substituent of the azaindole was easily converted into both quinoxaline and triazole substituents, the latter utilizing an alkyne-azide cycloaddition reaction. Some of these azaindole derivatives showed very promising biological activity against the gastrointestinal protozoal parasite Giardia duodenalis.
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