How will you bring about the following conversions : (i) Phenol to Aspirin (ii) Aniline to phenol (iii) Phenol to Anisole.

To convert one compound into another in organic chemistry, we often use a series of chemical reactions that involve specific reagents and conditions. Let's break down the conversions you've mentioned: phenol to aspirin, aniline to phenol, and phenol to anisole. Each of these transformations involves distinct pathways and reactions.

Transforming Phenol to Aspirin

Aspirin, or acetylsalicylic acid, can be synthesized from phenol through a multi-step process. Here’s how it works:

• Step 1: Formation of Salicylic Acid - First, phenol is converted to salicylic acid. This is typically done through a reaction with carbon dioxide (CO2) under high pressure and temperature in the presence of a base like sodium hydroxide (NaOH). This process is known as the Kolbe-Schmitt reaction.
• Step 2: Acetylation - The next step involves acetylating salicylic acid to form aspirin. This can be achieved by reacting salicylic acid with acetic anhydride or acetyl chloride. The reaction results in the formation of aspirin and acetic acid as a byproduct.

Converting Aniline to Phenol

The transformation of aniline (an amine) to phenol (an alcohol) can be accomplished through a process called oxidation. Here’s a step-by-step breakdown:

• Step 1: Diazotization - Aniline is first treated with nitrous acid (generated in situ from sodium nitrite and hydrochloric acid) to form a diazonium salt.
• Step 2: Hydrolysis - The diazonium salt can then be hydrolyzed by heating it with water, which leads to the formation of phenol. This reaction typically occurs under acidic conditions.

Changing Phenol to Anisole

To convert phenol to anisole (methoxybenzene), a methylation reaction is employed. Here’s how this transformation can be achieved:

• Methylation Reaction - Phenol can be methylated using methyl iodide (CH3I) in the presence of a strong base like sodium hydride (NaH) or potassium carbonate (K2CO3). The base deprotonates the hydroxyl group of phenol, making it a better nucleophile, which then attacks the methyl iodide, resulting in the formation of anisole.

Each of these conversions showcases the versatility of organic reactions and the importance of understanding reaction mechanisms. By carefully selecting reagents and conditions, we can effectively transform one compound into another, paving the way for the synthesis of various important organic molecules.