Synthesis of the naphthoic acid component of kedarcidin chromophore by routes employing photochemical and thermal electrocyclic ring closure reactions.

Two different synthetic routes to the naphthoic acid component of kedarcidin chromophore were developed featuring photochemical and thermal electrocyclic ring closure reactions, respectively, as the key step. X-ray crystallographic analysis of the synthetic naphthoic acid confirmed its structure and comparison of H-1 and C-13 NMR data from its methylamide derivative with those reported for kedarcidin chromophore correspond closely, suggesting that this component of the natural product is correctly assigned. (C) 1997 Elsevier Science Ltd.