Chapter 15, Problem 80CP

(a)

Interpretation Introduction

Interpretation:

The aromatic proton which gives rise to the most downfield signal and the choice has to be justified.

Concept introduction:

NMR spectroscopy:

It is the study of the interaction between electromagnetic radiation and the nuclei of atoms and the variety of nuclei studied includes ${}^{\text{1}}\text{H,}{}^{\text{13}}\text{C,}{}^{\text{15}}\text{N,}{}^{\text{19}}\text{F}\text{and}{}^{\text{31}}\text{P}$

${}^{\text{1}}\text{H NMR}$: A technique gives information to predict the Carbon and Hydrogen connectivity in the organic compounds.

Chemical shift: The frequency of the proton signal in the spectrum with reference to the standard compound  which may be TMS (Tetramethylsilane) shows signal at 0 ppm(parts per million).

Multiplicity: The number of peaks on the each signal in NMR spectrum is defined as multiplicity; the multiplicity of each signal indicates the neighboring protons. It is generated by coupling of the subjected protons with the neighboring protons (both subjected and neighbor protons are to be chemically not equivalent) separated by either two or three sigma bonds.

(b)

Interpretation Introduction

Interpretation:

The three signals in the compound 2 is whether expected to be upfield or downfield and the reason has to be given.

Concept introduction:

NMR spectroscopy:

It is the study of the interaction between electromagnetic radiation and the nuclei of atoms and the variety of nuclei studied includes ${}^{\text{1}}\text{H,}{}^{\text{13}}\text{C,}{}^{\text{15}}\text{N,}{}^{\text{19}}\text{F}\text{and}{}^{\text{31}}\text{P}$

${}^{\text{1}}\text{H NMR}$: A technique gives information to predict the Carbon and Hydrogen connectivity in the organic compounds.

Chemical shift: The frequency of the proton signal in the spectrum with reference to the standard compound  which may be TMS(Tetramethylsilane) shows signal at 0 ppm(parts per million).

Multiplicity: The number of peaks on the each signal in NMR spectrum is defined as multiplicity; the multiplicity of each signal indicates the neighboring protons. It is generated by coupling of the subjected protons with the neighboring protons (both subjected and neighbor protons are to be chemically not equivalent) separated by either two or three sigma bonds.