Question

Which of the following compounds is easier to decarboxylate?

or

Short answer

The reactivity of pyridine is low towards an electrophilic substitution reaction because of the presence of an electron withdrawing nitrogen atom.

A pyridine undergoes such a reaction under vigorous conditions. It is more reactive towards a nucleophilic substitution reaction.

Step-by-step solution

Reactivity of pyridine 

The reactivity of pyridine is low towards an electrophilic substitution reaction because of the presence of an electron withdrawing nitrogen atom.

A pyridine undergoes such a reaction under vigorous conditions. It is more reactive towards a nucleophilic substitution reaction.

Identifying the compound that is easier to decarboxylate

Compounds

The compound shown on the right is easier to decarboxylate as the electrons left behind when the carbon dioxide is removed can be delocalized into nitrogen, generating a stable neutral species because of the proton donation to nitrogen.

Decarboxylation of the compound on the right

The electrons left behind when the other compound loses the carbon dioxide cannot be delocalized.