Synthesis of Highly Modified Porphyrinoid Systems

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This project will continue work on the synthesis, characterization, and reactivity of porphyrin-like macrocycles, including carbaporphyrins. In previous studies, a '3 + 1' methodology was developed for the preparation of carbaporphyrinoid systems, and this approach will be applied to the synthesis of new porphyrin analogues with pyrazole, isoxazole or related subunits. Further investigations will be conducted on the chemistry of known carbaporphyrinoid systems, including metalation reactions. A new '2 + 2' methodology for synthesizing adj-dicarbaporphyrinoids from fulvenes will also be developed and the same strategy will be used to prepare further modified porphyrinoid structures. In addition, diindenylmethane will be used as a precursor to novel conjugated macrocycles, and dipyrrylmethanes with two inverted pyrrole rings will be used to prepare a new class of doubly N-confused porphyrins. Pyrroles with acrylaldehyde substituents will be used to synthesize new examples of vinylogous porphyrins and sapphyrins, and McMurry coupling of bisacrylaldehydes will be used to generate dideazaporphyrins. The new porphyrin-type structures have great theoretical significance and will provide insights into the aromatic character of oligopyrrolic macrocycles. These structures will also allow the preparation of novel organometallic derivatives with interesting and potentially useful catalytic properties. Porphyrin analogues of this type are also being investigated as potential agents for photodynamic therapy and in the treatment of leishmaniasis, and the new porphyrinoids are likely to show significant biological activity. The new macrocycles will be thoroughly characterized by spectroscopic methods and, where possible, X-ray crystal structures will be obtained. With this award, the Organic and Macromolecular Chemistry Program supports Professor Timothy D. Lash of Illinois State University whose research has important implications for the fields of heterocyclic and organometallic chemistry, and may lead to applications as diverse as catalysis and medicine. Hence, these projects not only provide an excellent environment for training undergraduates and MS level graduate students in the field of organic synthesis, but they also expose them to the multidisciplinary nature of modern scientific research.