Range Coupling in Aromatic Compounds

The lowest field resonance is for the hydrogen atom at C-3, which is ortho to both the bromine atom and the nitro group. The resonance of the hydrogen atom at C-5 is close to the C-3 hydrogen resonance. However, it is a doublet of doublets because it is coupled to the ortho hydrogen atom at C-6 and the meta hydrogen atom at C-3. 

Explain how 2,3,4-trichloroanisole, 2,3,5-trichloroanisole can be established using the coupling constants of the two doublets in the NMR spectrum of each compound. 

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