Q36E - Organic Chemistry (Mcmurry)

Question

Question: Loratadine, marketed as an antiallergy medication under the name Claritin, has four rings, eight double bonds, and the formula C₂₂H_?CIN₂O₂ . How many hydrogens does loratadine have? (Calculate your answer; don’t count hydrogens in the structure.)

Step-by-Step Solution

Answer

Answer

The number of hydrogens in loratidine is 23.

Step 1: Number of hydrogens in a compound

The count of hydrogens in a particular compound can be identified from the degree of unsaturation. It can be found from the formula:

 $\mathbf{\text{Degree of unsaturation = }}\frac{\mathbf{\text{2C + 2 + N - H - X}}}{\mathbf{\text{2}}}$

Step 2: Number of hydrogens in loratadine

Loratidine has four rings and eight double bonds. The number of hydrogens in loratadine can be found from the degree of unsaturation as:

 $$\begin{gathered} \text{Degree of unsaturation = }\frac{\text{2C + 2 + N - H - X}}{\text{2}} \\ 12=\frac{2\times 22+2+2-x-1}{2} \\ 12=\frac{47-x}{2} \end{gathered}$$

On further solving:

 $$\begin{gathered} 12=\frac{47-x}{2} \\ 24=47-x \\ x=47-24 \\ =23 \end{gathered}$$

Hence, the number of hydrogens in loratidine is 23.