Q 57P - Organic Chemistry (Mcmurry)

Question

Question: The NMR spectra of compound A, , are shown. Propose a structure for A, and assign peaks in the spectra to your structure.

Step-by-Step Solution

Answer

Step-by-Step Solution Step 1: Non-Equivalent and Equivalent proton

The proton which are having the different environment and all proton give different peaks are the non-equivalent proton whereas the proton shares the same environment and all protons that gave the same singles or peaks are the equivalent protons.

Step 2: Signal production

All equivalent proton produces a single signal and all the non-equivalent proton produces a separate signal for each proton.

Step 3: Signal splitting

As the signal is produced by the proton is divided into subparts like 1H atom produce multiplet due to the different environment

If a methyl group is surrounded by other methyl groups produces a doublet.

Step 4: H 1   NMR

Nuclear magnetic resonance is the technique that is used to identify the hydrogen in the compound and produce the corresponding peaks for its detection.

Step 5: Structure of compound A

rings that are symmetrical because forming six peaks saturated carbon accounts for two peaks at 15,28ppm and unsaturated carbon accounts for other four peaks at 119,129,131,143ppm          

In the peak, graph shows the triplet due to 3H at 120 and quartet due to 2H at 120, and other signals due to the four-ring protons

 

Hence, the structure must be as:

                                    Compound A