Q48P - Organic Chemistry (Mcmurry)

Question

Using ${}^{\mathbf{13}}\mathit{C}{\mathit{O}}_{\mathbf{2}}$ as your only source of labelled carbon, along with any other compounds needed, how would you synthesize the following compounds?

1. $\mathit{C}{\mathit{H}}_{\mathbf{3}}\mathit{C}{{\mathbf{H}}_{\mathbf{2}}}^{\mathbf{13}}\mathit{C}{\mathit{O}}_{\mathbf{2}}\mathit{H}$
2. $\mathit{C}{{\mathbf{H}}_{\mathbf{3}}}^{\mathbf{13}}\mathit{C}{\mathit{H}}_{\mathbf{2}}\mathit{C}{\mathit{O}}_{\mathbf{2}}\mathit{H}$
   

 

Step-by-Step Solution

Answer

(a) The synthesis of  $C{H}_{3}C{H_2}^{13}C{O}_{2}H$ using ${}^{13}C{O}_2$  as the only source of labelled carbon and using any other compounds needed is 

(b) The synthesis of $C{H_3}^{13}C{H}_{2}C{O}_{2}H$  using ${}^{13}C{O}_2$  as the only source of labelled carbon and using any other compounds needed is

Step 1: Definition of compounds

Any substance composed of identical molecules consisting of atoms of two or more chemical elements is defined as a chemical compound.

Step 2: Explanations

(a) By using  ${}^{13}C{O}_2$ as the only source of labelled carbon, propionic acid with COOH carbon labelled is to be prepared. Two other carbons are needed. So ethyl magnesium bromide prepared by treating ethyl bromide with Mg in dry ether is treated with ${}^{13}C{O}_2$.

The synthesis of  $\mathit{C}{\mathit{H}}_{\mathbf{3}}\mathit{C}{{\mathbf{H}}_{\mathbf{2}}}^{\mathbf{13}}\mathit{C}{\mathit{O}}_{\mathbf{2}}\mathit{H}$ using  ${}^{\mathbf{13}}\mathit{C}{\mathit{O}}_{\mathbf{2}}$ as the only source of labelled carbon and using any other compounds needed is

(b) By using ${}^{13}C{O}_2$  as the only source of labelled carbon propionic acid with carbon adjacent to carboxyl group is labelled is to be prepared. Two other carbons are needed. So ethyl magnesium bromide with carbon adjacent to carboxyl group labelled is prepared and treated with $C{O}_2$

The Grignard reagent when treated with ${}^{13}C{O}_2$  and acidified is converted into acetic acid with the carboxyl carbon labelled. 

This Grignard reagent, when treated with normal $C{O}_2$  yields propanoic acid with the labelled carbon adjacent to the carboxyl group.

The synthesis of $\mathit{C}{{\mathbf{H}}_{\mathbf{3}}}^{\mathbf{13}}\mathit{C}{\mathit{H}}_{\mathbf{2}}\mathit{C}{\mathit{O}}_{\mathbf{2}}\mathit{H}$  using ${}^{\mathbf{13}}\mathit{C}{\mathit{O}}_{\mathbf{2}}$  as the only source of labelled carbon and using any other compounds needed is