PFG-HMBC 2D NMR spectrum

Figure 4, PFG-HMBC 2D NMR spectrum of 1 (a) and (b) the expansions of alkoxy regions (c) and (d) the expansions of aliphatic regions and (e) the downfield (aromatic and carbonyl) regions.

The H NMR spectrum of 1 (Figure 1) shows resolved resonances for all the protons in the structure except for some of the aliphatic methylene protons in the long aliphatic chain. However, the C NMR spectrum (Figure 2) displays nicely resolved resonances for each carbon in the structure, including those in the long aliphatic chain. Therefore by using PFG HMQC and HMBC 2D NMR experiments, the proton resonances can be dispersed based on the resolved carbon resonances. 

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