Identification of the configuration of neosartorin by long-range nuclear overhauser effect measurements

The relative configuration of the two xanthene units of neosartorin, a new ergochrome biosynthesised by the soil mould Neosartorya fischeri, was deter mined using a 1D double-pulsed field gradient spin-echo NOESY experiment. I t was found that both units have the same relative stereochemistry. Long-ra nge nonbonding interactions between the substituents of different xanthene units stabilise the nonplanar configuration of the two aromatic rings A and A' connecting both monomer units of neosartorin. Chirality 13:545-547, 200 1. (C) 2001 Wiley-Liss, Inc.