Fig. 2From: Synthesis of typical sulfonamide antibiotics with [14C]- and [13C]-labeling on the phenyl ring for use in environmental studies13C-NMR spectra of [13C]-SMX (5b), [13C]-SMM (7b), and [13C]-SDZ (10b). The positions of the numbered C-atoms are given in the corresponding structure of the [13C]-labeled SAs. The red and black lines represent the spectra of SAs with [13C]-labeling or natural 13C-abundance. The signal of the C-atoms at the [13C]-labeled benzene ring is enlarged. The chemical shifts of the numbered C-atoms with natural abundance are listedBack to article page