Synthesis and characterization of a new natural product analog, 132-173-bacteriochlorophyllone a

Roxin Á, MacDonald TD, Zheng G

Journal of Porphyrins and Phthalocyanines, 2014

DOI: 10.1142/S1088424613501058

Here we show the facile synthesis of 13²-17³-bacteriochlorophyllone a (12), with a distinct seven-membered exocyclic F-ring formed by 13²-17³-cyclization of bacteriopheophorbide a(16). This is the latest reported bacteriochlorin with such an exocyclic F-ring since 1975 (13²-17³ cyclobacteriopheophorbide a-enol, 11), and is an analog of previously described natural exocyclic F-ring-containing porphyrins (1–4) and chlorins (5–10). The structure of 12 was confirmed using a combination of 1D ¹H NMR, 2D COSY ¹H NMR, Jmod ¹³C NMR and HRMS analysis. The biological activity of 12 was explored, and we found that this compound does not possess strong antioxidant activity like its natural product counterparts, but is a capable photosensitizer for photodynamic therapy.