Chapter 3, Problem 3.14P

Explain why the boiling point of propanamide, ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}{\text{CONH}}_{\text{2}}$ is

considerably higher than the boiling point of $N,N-\text{dimethylformamide}$, $\text{HCON}\left({\text{CH}}_{\text{3}}\right)-\left({\text{213 }}^{\text{ο}}\text{C vs}{\text{. 153 }}^{\text{ο}}\text{C }\right)$, even though both compounds are isomeric amides.