Acetylation: Overview, Reaction, Mechanism, FAQs

The process by which an acetyl group is added to a compound by replacing an active hydrogen atom is called acetylation. Here, an acetyl group consisting of a carbonyl or carbon atom paired with oxygen and a CH3 or methyl end group combines to form CH3CO, often denoted as "R". Such reactions occur because a desired leaving group (R) and nucleophilic (NP) have an extra electron to form acetate.

Acetylation

There are many examples of powerful acetylation reactions that can enhance our overall understanding of acetylation. Example: In the acetylation of glucose, a simple bond between the acetyl group and an extra electron on the nucleophilic oxygen facilitates easy replacement of the hydrogen atom on the phenolic group.

A strong leaving group is required for the acetylation of the acetyl group, so a strong acetylating agent such as acetic anhydride is required for successful acetylation. The process of acetylation, which is used in several synthetic processes such as aspirin, proteins and other useful medical purposes, occurs widely in nature and artificially in the laboratory.

Salicylic Acid Acetylation Reaction

Salicylic acid is acetylated with the help of acetic anhydride to produce acetylsalicylic acid (commonly known as aspirin) and acetic acid as end products. Note that acetic anhydride is also used as an acetylating agent in the synthesis of THC acetate and diacetylmorphine.

Mechanism Of Acetylation Of Salicylic Acid

Acetylation of salicylic acid occurs in acidic environments. Here, an acidic medium (usually concentrated sulfuric acid) helps separate the acetate ion from the acetic anhydride. This acetate ion continues to combine with the protons released by the phenolic OH group (hydroxy group) of the salicylic acid molecule and forms acetic acid (CH3COOH). An acetylation reaction mechanism occurs in which salicylic acid gives aspirin and acetic acid as products.

First, an oxygen atom of acetic anhydride is protonated by acid. The resulting positive charge is transferred to the adjacent carbonyl carbon and is itself bonded to the hydroxyphenyl group. This intermediate is deprotonated and a molecule of acetic acid remains. Thus, the necessary products (aspirin and acetic acid) are formed.

Acetylation With Acetic Acid

Another smooth and powerful acetylation reaction of alcohols and phenols uses zirconium oxide and boron as catalysts. The acetylation process occurs when an alcohol is introduced into acetic acid at high temperature using toluene as a solvent, and an acetylated compound is obtained that utilises the power of zirconia borate.

Acetylation Of Amines

There are several methods that allow the acetylation of some amines using catalytic acetic acid, ethyl/butyl acetate as the acetylating agent. It is usually used to form formamide at low room temperature (20°C). There are several other examples of acetylation reactions like- N-acetylation of amines from N,N-dimethylacetamide.

Dimethylacetamide acts as an efficient reservoir for the synthesis of acetyl and dimethylamine gases. When treated at 120-125°C, some amines can be easily acetylated and act as surrogates for the rest of the acetylation scheme.

N-Alpha Acetyltransferase

These intermediate compounds enable various acetylation reactions. These compounds, named after canonical variables used in molecular motion, are known to exist intracellularly to regulate protein formation.

The Histone Acetylation And Deacetylation

Proteins that copy DNA to repair damaged genetic material must act through acetylation to help us understand the energetics and precision of gene copying. These chemical reactions used in lysine and other gene regulatory activities may involve removing the acetyl group from the formula.

Acetylation Reaction

These reactions fall under the IUPAC criteria and regulations for ethanoylation. It often involves introducing an acetyl function into an acidic base to replace the hydroxyl group. The reverse chemical reaction, aka deacetylation, which results in the complete removal of the acetyl group in the formula, also falls under the same IUPAC nomenclature. It also helps in the biotransformation of drugs, including how the body processes and disposes of drugs through acetylation reactions.