91Ó°ÊÓ

An organic compound can be converted into another by treating it with various reagents sequentially and systematically.

Synthesis (c)

a. In the given case, primary alcohol has to be converted into secondary alcohol.

The conversion can be carried out as follows:

Synthesis (a)

The reagent POCl₃ , pyridine, is a dehydrating agent and can be used to convert the alcohol to its corresponding alkene.

The reaction of an alkene with H₂O,H₂SO₄ yields secondary alcohol as the OH group adds on the more substituted carbon atom.

b.

Synthesis (b)

The reaction of an alkyl bromide with a strong base yields alcohol as the Br (bromine) group is replaced by the OH (hydroxyl) group.

The dehydration of alcohol yields the corresponding alkene that can be converted into primary alcohol by hydroboration oxidation.

The alcohol can be converted into an alkoxy group by treating it with a strong base followed by a reaction with an alkyl halide (preferably alkyl iodide).

c.

Synthesis (c)

The reaction involves the conversion of alkyl halide into an alkene by the reaction of the alkyl halide with an alkoxy base.

The desired secondary alkyl chloride can be obtained by treating the alkene molecule with hydrochloric acid (Markonikov’s addition).

d.

Synthesis (d)

The reaction of an alkene with a bromine molecule(Br₂) yields vicinal dibromide.

The vicinal dibromide on reaction with two equivalents of NaNH₂ (sodium amide) yields the corresponding alkyne.

e.

Synthesis (e)

The alkyl bromide is converted into an alkene by treating it with a base followed by a dehydrating agent.

The alkene is then converted into alkyne by treating it with and two equivalents of sodium amide.

f.

Synthesis (f)

The following reaction involves the conversion of alkyl halide into an epoxide.

The alkyl halide is first converted into an alkene.

The reaction of the obtained alkene with bromine molecule in the presence of water (i.e., in aqueous medium) leads to the addition of OH group on the more substituted carbon and Br on the less substituted one.

The reaction of this compound with a strong base (such as NaH) yields the desired epoxide.