91Ó°ÊÓ

Aromatic five-membered heterocyclic compounds get subjected to the electrophilic aromatic substitution, preferably at the second position. The intermediate acquired by adding a substituent to this position is more stable than the one at the third position.

a. In this reaction, the pyrrolidine reacts with the benzoyl chloride to form phenyl (pyrrolidin-1-yl) methanone as the product. The reaction is shown below.

Reaction (a)

b. In this reaction, 2-bromopyridine reacts with ${}^{−}\mathrm{OH}$ and heat to form pyridin-2(1H)-one as the product. The reaction is shown below.

Reaction (b)

c. In this reaction, 1-bromobutane reacts with the cyanide followed by ${\mathrm{H}}_2$and Raney nickel to form pentanamine. The reaction is shown below.

Reaction (c)

d. In this reaction, 2-methylfuran reacts with the acetyl chloride to form 1-(5-methylfuran-2-yl) ethanone as the product. The reaction is shown below.

Reaction (d)

e. In this reaction 2-chloropyridine reacts with the phenyllithium to generate 2-phenylpyridine as the product. The reaction is shown below.

Reaction (e)

f. In this reaction, the cyclcohexananmine reacts with 1-bromopropane to form N-propylcyclohexanamine. The reaction is shown below.

Reaction (f)

g. In this reaction, the pyrrole reacts with the benzenediazonium to form (E)-2-(phenyldiazenyl)-1H-pyrrole as the product. The reaction is shown below.

Reaction (g)

h. In this reaction, 2-methylpyridine reacts with ${}^{−}\mathrm{NH}_2$and 1-bromopropane to form 2-butylpyridine as the product. The reaction is shown below.

Reaction (h)

i. In this reaction, 2-bromothiophene reacts with the Mg, ${\mathrm{Et}}_2\mathrm{O}$, carbon dioxide, and HCl to form thiophene-2-carboxylic acid as the product. The reaction is shown below.

Reaction (i)