Analysis of multiplets in two-dimensional NMR spectra by topological classification: applications to vinblastine and cyclosporin A

A recently developed approach for the anal. of cross-peak multiplets was applied to 2-dimensional correlation spectra of the binary alkaloid vinblastine and the cyclic undecapeptide cyclosporin A. The exptl. multiplet patterns are encoded in a manner that depends on the topol. of the coupling network but not on the values of the coupling consts. Multiplets that are expected to occur for various possible coupling networks are similarly encoded in a library to allow comparison with exptl. multiplets. The program is called MARCO POLO (Multiplet Anal. by Redn. of Cross peaks and Ordering of Patterns in an Overdetd. Library Organization). The outcome of this type of automated anal. is discussed in detail, with particular emphasis on remaining ambiguities. [on SciFinder (R)]