Consider the following 1H-NMR (400 MHz, DMSO-d 6) data of a compound: in ppm: 3.85 (s, 6H), 6.73 (t, J=2.2 Hz, 1H), 7.1 (d, J=2.2 Hz, 2H), and 13.05 (brs, 1H). The compound is

GATE 2024 CY – Question 40

Organic Chemistry · Experimental Techniques in Organic Chemistry: Optical rotation (polarimetry). Application of various chromatographic techniques such as thin-layer, column, HPLC and GC. Applications of UV-visible, IR, NMR spectroscopy and Mass spectrometry in the structural determination of organic molecules. · 2 marks · Multiple choice

Consider the following $^1$H-NMR (400 MHz, DMSO-$d_6$) data of a compound: $\delta$ in ppm: 3.85 (s, 6H), 6.73 (t, $J=2.2$ Hz, 1H), 7.1 (d, $J=2.2$ Hz, 2H), and 13.05 (brs, 1H). The compound is

Four substituted benzoic acid structures.

Option A in the figure
Option B in the figure
Option C in the figure
Option D in the figure

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Correct answer: (B) Option B in the figure

Explanation

Two equivalent methoxy groups give the 6H singlet. A symmetric 3,5-disubstituted benzoic acid has two equivalent H2/H6 protons giving the doublet and H4 giving the meta-coupled triplet; the acid proton is at 13.05 ppm.