Isolation and structure determination of two novel C(132)–OH bacteriopheophytin a allomers from a coastal salt pond sediment

We report the isolation and structure determination [RP-18 HPLC, UV-Vis, MS, 1H NMR, and two-dimensional 1H NMR (COSY and ROESY)] of two novel C(132)–OH bacteriopheophytin a allomers from a coastal salt pond sediment (Salt Pond, MA, USA). These allomers are formed by oxidative transformation of bacteriochlorophyll a and/or bacteriopheophytin a, and may play, through fossilization, an important role as intermediates on the formation of some ETIO porphyrins isolated early from sediments.