1. PROTECTION & DEPROTECTION OF
CARBONYL GROUP
Mr. Soumyadeep Paul
M.PHARM 1st year
(Pharmaceutical
chemistry)
2. Some example of
C=O & COOH
protecting group
C=O & COOH Protecting
group
Content
Introduction
About protection &
deprotection.
Role of protecting group in
organic synthesis.
Property of Protecting
group
Type of protecting group &
their property.
3. Introduction
In organic chemistry, protection and deprotection strategies
are essential for safeguarding reactive functional groups
during synthesis. These methods temporarily modify groups
to prevent undesired reactions, ensuring precision in
molecular design. The orchestrated use of these protocols
enables accurate manipulation of structures in complex
synthetic pathways, contributing significantly to
advancements in diverse scientific applications.
4. How it
works
Without protecting group
(a non-selective
oxidation)
By Using protecting
group (a selective
oxidation Take place)
5. Role of Protecting
group in organic
Synthesis
Preservation of Reactivity: Protecting groups shield
reactive functional groups, preventing unintended reactions
during complex synthesis.
Multi-step Synthesis: Essential in multi-step processes
where different reactive sites coexist, ensuring controlled and
selective reactions.
Temporary Modification: Involves reversible alterations to
functional groups, facilitating their restoration to the original
state after desired synthetic steps.
Precision in Molecular Design: Enables chemists to
navigate intricate synthetic pathways with accuracy, ensuring
the precise construction of complex organic molecules.
6. Versatility: Widely employed across various synthetic
methodologies, contributing to the synthesis of
pharmaceuticals, materials, and diverse organic compounds.
Advancement of Scientific Knowledge: Critical role in
advancing synthetic methodologies, enhancing our
understanding of molecular structures, and broadening
applications in scientific research and industry.
7. Ideal Property of Protecting group
Reactivity and Selectivity:
Protecting groups should selectively react with specific functional groups without affecting
others, minimizing side reactions.
Orthogonality:
They should be orthogonal, allowing for selective introduction and removal without
interfering with other groups.
Stability:
Stability under various conditions is crucial to prevent premature removal during synthesis.
Efficient Installation and Removal:
Easy installation and removal under mild conditions enhance overall synthetic efficiency.
Solubility:
Protecting groups should be soluble in common solvents for homogeneous reactions.
Commercial Availability:
Ideally, they should be commercially available to reduce synthetic costs.
8. Commercial Availability:
Ideally, they should be commercially available to reduce synthetic costs.
Compatibility with Analytical Techniques:
They should not interfere with common analytical methods.
Inertness:
Protecting groups should be inert to reagents and conditions encountered during synthesis.
Chemo selectivity:
They should selectively protect one functional group in the presence of others.
Environmental and Safety Considerations:
Consideration for environmental impact and safety is essential.
Compatibility with Subsequent Reactions:
Deprotected functional groups should be compatible with subsequent steps.
Robustness:
Protecting groups should be robust, tolerating variations in reaction conditions.
In essence, the ideal protecting group is reactive, selective, stable, and practical, facilitating complex
molecule synthesis in organic chemistry.
10. E
C=O protecting group example
The application of this process is Wieland-Miesher Ketone a common
Intermediate for both natural and Synthetic Steroids
11. COOH protecting group
Protection of carboxlyc acid are used to avoid reaction of the acidic –COOH hydrogen
with bases and nucleophile to Prevent Nucleophile addition at the carbonyl carbon
Most common group to Protect COOH is esterification
