Hydrolysis of Amides
Reaction type: Nucleophilic
Acyl Substitution
Summary
- Amides hydrolyse to the parent carboxylic acid and the
appropriate amine.
- The mechanisms are similar to those of esters.
- Reagents : Strong acid (e.g. H2SO4)
/ heat (preferred) or strong base (e.g. NaOH) / heat.
Related Reactions
Reaction under ACIDIC conditions:
- Note that the acid catalysed mechanism is analogous to
the acid catalysed hydrolysis of esters.
- The mechanism shown below proceeds via protonation of
the carbonyl not the amide N (see step 1).
- The mechanism is an example of the less reactive system type.
MECHANISM OF THE ACID CATALYSED HYDROLYSIS OF AMIDES
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Step 1:
An acid/base reaction. Since we only have a
weak nucleophile and a poor
electrophile we
need to activate the amide.
Protonation of the
amide carbonyl makes it more
electrophilic.
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Step 2:
The water O functions as the nucleophile attacking
the electrophilic C in the C=O,
with the electrons
moving towards the oxonium ion,
creating the
tetrahedral intermediate.
Step 3:
An acid/base reaction. Deprotonate the oxygen that
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came from the water molecule to
neutralise the charge.
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Step 4:
An acid/base reaction. Need to make the -NH2 leave,
but need to convert it into a good
leaving group
first by protonation.
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Step 5:
Use the electrons of an adjacent oxygen to help
"push out" the leaving group, a
neutral ammonia
molecule.
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Step 6:
An acid/base reaction. Deprotonation of the oxonium
ion reveals the carbonyl in the carboxylic
acid product
and regenerates the acid catalyst.
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hy desi, I wanna ask you,what is the Difference between acidic hydrolysis and basic hydrolysis in amide?
BalasHapusthanks for your question, i think the answer is:
BalasHapusAn amide hydrolysis can take place under acidic or basa.Dalam acidic environment, the reaction occurs between the water and the protonated amide has produced a carboxylic acid -NH3
In alkaline environment, OH-attack on the amide and carboxylic acid anions produce +NH3