ACYL TUNICHLORINS - A NEW CLASS OF NICKEL CHLORINS ISOLATED FROM THE CARIBBEAN TUNICATE TRIDIDEMNUM-SOLIDUM

A new class of nickel-containing chlorins (acyl tunichlorins) has been isolated from the Caribbean tunicate Trididemnum solidum, The structu res of 28 of these nickel(II) hydroporphyrins were elucidated using ma ss spectrometry, one- and two-dimensional NMR spectroscopy, and chemic al degradation/derivatization. Unique structural features of these com pounds include the diversity of aliphatic side chains, which are deriv ed from C-14:0 to C-22:6 fatty acids, and their location at an unprece dented position at C-2a on the hydroporphyrin nucleus, No chlorins wit h ester-linked acyl side chains at C-2a have been reported previously, Although the exact biological role that these compounds play in T. so lidum remains unknown, acyl tunichlorins represent the only nickel-con taining chlorins to be isolated from a living system and are the C-2a acyl derivatives of tunichlorin, a nickel chlorin reported by this lab oratory in 1988.