The $^1$H-NMR spectral data of a compound X is as follows: $\delta$ (ppm): 11.6 (s, 1H, exchangeable with D$_2$O), 7.60 (d, 1H, $J = 7.2$ Hz), 7.20 (t, 1H, $J = 7.2$ Hz), 6.90 (d, 1H, $J = 7.2$ Hz), 3.70 (s, 3H), 3.58 (s, 3H)Based on the spectral data, choose the appropriate structure for compound X.
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In aromatic $^1$H-NMR, a d-t-d pattern usually indicates three adjacent aromatic protons in a 1,2,3-trisubstituted benzene ring
Step 1: Identify the acidic proton.
The signal at $\delta$ 11.6 ppm is a singlet and is exchangeable with D$_2$OThis indicates the presence of a carboxylic acid proton, i.e., $-$COOH group
Step 2: Identify methoxy groups.
The two singlets at $\delta$ 3.70 ppm and $\delta$ 3.58 ppm, each integrating for 3H, indicate the presence of two methoxy groups, $-$OCH$_3$ and $-$OCH$_3$
Step 3: Analyze aromatic proton pattern.
The aromatic region shows three protons:
\[
7.60 \; (d, 1H, J = 7.2 \text{ Hz})
\]
\[
7.20 \; (t, 1H, J = 7.2 \text{ Hz})
\]
\[
6.90 \; (d, 1H, J = 7.2 \text{ Hz})
\]
This $d-t-d$ pattern indicates three adjacent aromatic hydrogensThis is characteristic of a 1,2,3-trisubstituted benzene system
Step 4: Match with the given structures.
The compound must contain one $-$COOH group and two non-equivalent methoxy groups arranged so that three adjacent aromatic protons remainOnly option (B) satisfies this condition
