Neocarzinostatin: Chemical characterization and partial structure of the non-protein chromophore

The molecular formula C₃₅H₃₅NO₁₂ (mol.wt. 661) is proposed for the biologically active chromophoric component of neocarzinostatin. The partial structure $\text{2}$ is proposed based on ${}^1\text{H}$ NMR and mass spectral data and consists, in part, of a 2,6-dideoxy-2-methylamino-galactose moiety and a naphthoic acid derivative. Special treatments required to obtain spectral data of the labile chromophore are described.