13C-NMR spectra and streochemistry of isoechinulins A, B and C.

Abstract
13C-NMR spectra of isoechinulins A, B and C, metabolites from Aspergillus Tuber, were fully assigned on the basis of chemical shifts and multiplicities and comparison with their analogues. Taking advantage of the symmetrical structure of the diketopiperazine ring, the stereochemistry of the trisubstituted carbon-carbon double bond in a dehydrotryptophyl moiety was determined as Z (cis) by measuring the coupling constants, J-HC=C-CO-, in the proton nondecoupled spectrum of isoechinulin B.

This publication has 0 references indexed in Scilit: