The COSY spectrum analysis indicated interactions between H-11 (δ 4.04) and H-9 (δ 1.15).
In addition, 1H-13C COSY NMR analysis provided evidence for a linkage between LA and 3HHx units in the polymer.
The HMBC and 1H 1H COSY spectral analysis (Fig. 2) confirmed the presence of two sesquiterpenes moieties, respectively, corresponding to heptelidic acid [15] and hydroheptelidic acid (4) [12].
The 1H 1H COSY NMR analysis (Additional file 1: Figure S2 (B)) showed that the anomeric proton (δ = 4.49 ppm) was in a close relationship with δ = 3.2 ppm, which was annotated to H-6 of epothilone by comparing our data with 1H NMR of previously identified epothilone A and pentoside of epothilone as epothiloneoside A by Zhao et al. [2010].
HCCH-COSY spectrum analysis is a good example of the use SI labeling techniques in living organisms, since the natural abundance of 13C 13C bonds is very low (1/100×1/100 = 1/10000), making them impossible to detect without SI amendment.
The above data were further assigned unambiguously by HSQC, 1H-1H COSY and HMBC analysis (Fig. 2 and Electronic supplementary material).
RHT was characterized by 1H NMR, 13C NMR, APT, COSY, FTIR, elemental analysis, and also its binding selectivity toward various metal ions was studied.
The results from 1H NMR and 1HH COSY NMR spectral analysis clearly points out the position of pyrazoline ring inside the cavity and its role in complexation process.
Combining the 1H- and 13C NMR data (Table 1) with the HSQC, COSY and HMBC analysis (Fig. 2), the skeletal structure of 1 was confirmed as a hopan-3-ol-28,22-olide.
These sensors were characterized by combination of 1H, 13C, APT, COSY NMR, FTIR, elemental analysis, and UV vis spectral data.
