The Application of Friedländer and Fischer Methodologies to the Synthesis of Organized Polyaza Cavities

The Friedländer reaction of β-aminoacrolein and ortho-aminoarenealdehydes and ortho-aminoheteroarenealdehydes with cyclic ketones and diketones provides a variety of polyaza cavity-shaped molecules. The conformation of the cavity is governed by the size of the ring containing the carbonyl group and the orientation of two carbonyls with respect to one another. Diaminodialdehydes and appropriate synthons can also be used to elaborate this approach. Alternatively, bridged terpyridines are also accessible through the reaction of an enamine with formaldehyde or an aromatic aldehyde. Analogous 2-(2′-pyridyl)indole systems can be prepared by an application of the Fischer indole synthesis to the same cyclic ketones while the use of 8-hydrazinoquinoline provides access to the pyrido[2,3-g]indole subunit. 1. Introduction 2. Pyridine Rings via the Friedländer Condensation 3. Enamine Approach to Terpyridines 4. Indole Containing Systems via the Fischer Reaction 5. Other Interesting Systems and Looking to the Future