Assignment of proton and carbon NMR signals of didemnin A in solution

Several one‐ and two‐dimensional techniques have been used to assign the 1 H and 13 C NMR spectra of the cyclic heptadepsipeptide didemnin A in DMSO. The composition and sequence of the amino acid residues was known beforehand and could be confirmed by heteronuclear proton–carbon long‐range couplings using the COLOC experiment and a recently proposed new inverse technique using Gaussian‐shaped pulses. The aliphatic methyl resonances of the isostatin, hydroxyisovalerylpropionyl, N ‐methylleucine and leucine residues were assigned by means of the TOCSY and NOESY techniques. Aliphatic carbon assignment was performed by inverse correlation via heteronuclear double quantum coherence.