Examination of the reaction course with different aldehydes in one-flask syntheses of meso-substituted porphyrins

ORGN 145

Jonathan S. Lindsey and G. Richard Geier III. Department of Chemistry, North Carolina State University, Campus Box 8204, Raleigh, NC 27695-8204

Acid catalyzed condensations of pyrrole + aldehyde leading to meso-substituted porphyrins were performed with aryl aldehydes bearing electron donating, electron withdrawing, or sterically bulky substituents, and alkyl aldehydes. The reaction course involving each aldehyde was examined by monitoring the yield of porphyrin (UV-vis spectroscopy), reaction of aldehyde (TLC), and oligomer composition (laser desorption mass spectrometry). Reaction reversibility was investigated via oligomer exchange experiments and studies of condensations of dipyrromethanes. The results of this study provide deeper insight into the reaction course of pyrrole + aldehyde condensations, including the effects of diverse substituents and the propensity for undesirable reversibility (leading to scrambling) in stepwise syntheses of meso-substituted porphyrins.

New Reactions and Methodology, Metal-Mediated Reactions, Heterocycles and Aromatics 8:00 PM-10:00 PM, Sunday, March 28, 2004 Anaheim Convention Center -- Hall A, Poster Division of Organic Chemistry The 227th ACS National Meeting, Anaheim, CA, March 28-April 1, 2004