Q. 26 E-a - Organic Chemistry (Mcmurry)

Question

Draw the structures of the following molecules:

(a) Biacetyl, ${\mathbf{C}}_{\mathbf{4}}{\mathbf{H}}_{\mathbf{6}}{\mathbf{O}}_{\mathbf{2}}$, a substance with the aroma of butter; it contains no rings or carbon–carbon multiple bonds.

Step-by-Step Solution

Answer

Step 1: Biacetyl

Biacetyl come under the category of organic compound and has the formula  ${\mathbf{C}}_{\mathbf{4}}{\mathbf{H}}_{\mathbf{6}}{\mathbf{O}}_{\mathbf{2}}$ . It is a vicinal diketone comprising two C=O groups.

Step 2: Structure of biacetyl

(a)The structure of biacetyl can be found with the help of degree of unsaturation of the molecule. The degree of unsaturation of the molecule can be found as:

$$\begin{gathered} \text{Degree of unsaturation = }\frac{\text{2C + 2 + N - H - X}}{\text{2}} \\ \text{ = }\frac{2\times 4+2+0-6-0}{2} \\ \text{ = }\frac{10-6}{2} \\ \text{ = 2} \end{gathered}$$

Here the C, N, H and X denote the number of carbon, nitrogen, hydrogen and halogen.

The compound has a degree of unsaturation of two. But according to the problem, the compound does not contain rings or carbon-carbon multiple bonds.

The structure of biacetyl can be given as: 

The other possible structures of biacetyl can be given as: