Question

Compound Q has molecular formula \({{\bf{C}}_{\bf{5}}}{{\bf{H}}_{\bf{9}}}{\bf{Cl}}{{\bf{O}}_{\bf{2}}}\). Deduce the structure of P from its \({}^{\bf{1}}{\bf{H}}\) and \({}^{{\bf{13}}}{\bf{C}}\)-NMR spectra.

Short answer

The structure of Q is as follows:

Step-by-step solution

Molecular structure

The most accepted arrangement of atoms and elements within a compound to satisfy the barriers of energy and steric effects is the molecular structure of a compound.

Analyzing data

Given data

Chemical formula =\({{\rm{C}}_5}{{\rm{H}}_9}{\rm{Cl}}{{\rm{O}}_{\rm{2}}}\)

\({\rm{The degree of unsaturation }}\left( {{\rm{IHD}}} \right){\rm{ = }}\frac{{\left( {\left( {{\rm{2n + 2}}} \right){\rm{ - x}}} \right)}}{{\rm{2}}}\)

where,

n = number of carbon atoms

x = (number of hydrogen atoms) + (number of halogen atoms) - (number of nitrogen atoms)

On substituting values,

\(\begin{array}{c}{\rm{The degree of unsaturation }}\left( {{\rm{IHD}}} \right){\rm{ = }}\frac{{\left( {\left( {{\rm{2 \times 5 + 2}}} \right){\rm{ - }}\left( {{\rm{9 + 1}}} \right)} \right)}}{{\rm{2}}}\\{\rm{ = 1}}\end{array}\)

The value of IHD suggests the presence of a pi-bond.

The five signals in \({}^{{\rm{13}}}{\rm{C}}\)-NMR suggests the presence of five different types of carbon atoms.

From the \({}^{\rm{1}}{\rm{H}}\)-NMR spectra,

• The quartet at 4.2 ppm attributes to 2H atoms corresponding to split of two methyl groups,
• The triplet at 1.3 ppm attributes to 3H atoms due to split of 2H’s atoms,
• The triplet at 2.8 ppm attributes to 2H atoms due to split of 2H’s atoms,
• The triplet at 3.7 ppm attributes to 2H atoms due to split of 2H’s atoms,

Proposing the structure

Structure of Q.