Improved synthesis of meso-tetrarylbenziporphyrins

CHED 585

Valerie R. Yant, vryant@ilstu.edu and Timothy D. Lash, tdlash@ilstu.edu. Department of Chemistry, Illinois State University, Normal, IL 61790-4160

Benziporphyrins 1 have emerged as valuable ligands for organometallic chemistry.  In this project, we have developed an efficient route to these porphyrin analogue systems.  1,3-Benzenedicarboxylic acids 2 were converted on to the corresponding diacyl chlorides, and then reacted with benzene or chlorobenzene under Friedel-Crafts conditions to generate a series of diketones.  Subsequent reduction with sodium borohydride gave excellent yields of dicarbinols 3.  Further reaction with 3 equivalents of pyrrole and 2 equivalents of an aromatic aldehyde in the presence of BF3·Et2O, followed by oxidation with DDQ, gave the tetraaryl substituted benziporphyrins 1.