The document discusses carbonyl compounds, which contain a carbonyl group (C=O). This includes aldehydes, ketones, carboxylic acids, amides, and acid chlorides. It describes the structure of the carbonyl group and how the C=O double bond is polarized towards oxygen. This polarization allows carbonyl compounds to undergo nucleophilic addition reactions. Aldehydes are generally more reactive than ketones for electronic and steric reasons. Examples of reactions include hydration, cyanohydrin formation, imine formation, acetal formation, oxidation, reduction, and Friedel-Crafts acylation. Qualitative tests and important carbonyl compounds and their uses are also outlined.

1. BY
VANA JAGAN MOHAN RAO M.S.Pharm, MED.CHEM
NIPER-KOLKATA
Asst.Professor, MIPER-KURNOOL
Email: jaganvana6@gmail.com

2. DID WE
USE IT IN
OUR DAILY
LIFE?
WHAT IS
THE
STRUCTUR
E?
WHICH
ATOMS
ARE
PRESENT ?
HOW CAN
WE
PREPARE
IT?
WHAT ARE
PROPERTIE
S OF IT?
ARE THEY
REACT
WITH ANY
REAGENTS
?

3. What are carbonyl compounds?
The compounds containing a carbonyl group ( C=O ) are called carbonyl compounds.
These compounds include aldehydes, ketones, carboxylic acids, amides and acid chlorides.

4. Structure of the carbonyl group
The carbonyl carbon is sp2 hybridized, and has a partially filled unhybridized p orbital
perpendicular to the σ framework.
The oxygen is also sp2 hybridized, with the 2 lone pairs occupying sp2 orbitals. This leaves one
electron in a p orbital.
These p orbitals form the carbon oxygen π bond.
The C=O double bond is like a C=C double bond except the carbonyl double bond is shorter and
stronger.

5. The carbonyl group has a large dipole moment due to the polarity of the double bond.
Oxygen is more electronegative than carbon, and so the bond is polarized towards the
oxygen.
The attraction of the weakly held π electrons toward oxygen can be represented by the two following
resonance structures.
The first resonance structure is the major contributor, but the other contributes in a small
amount, which helps explain the dipole moment.
It is this polarization that creates the reactivity of the carbonyl groups (carbon is
electrophilic/LA, and the oxygen is nucleophilic/LB).

7. SOME IMPORTANT EXAMPLES OF ALDEHYDES

9. SOME IMPORTANT EXAMPLES OF KETONES

19. ELECTROMERIC EFFECT
In case of compounds containing multiple bonds (double or triple covalent
bonds), the electron pair shifts completely towards more electronegative atom
under the influence of attacking agent.
The complete transference of a shared pair of electrons of a multiple bond
towards one of the atoms in the presence of an attacking reagent is known as
electromeric effect.
A multiple bond (double or triple bond) consists of sigma and pi bonds. Electrons
of pi bond are loosely held ( due to side way overlapping) and easily polarizable.
The atom which acquire the electron pair become positively charged while the
atom which leave /donate the electron, get the positive charge.

20. In the case of carbonyl group, the shift is always towards oxygen, i.e., more
electronegative atom.
 It is a temporary effect and comes into play in the presence of an attacking
reagent.
This effect commonly occur in addition reactions of Alkenes, alkynes, nitrile
and Carbonyl compounds.
 It is generally denoted as E effect.
It is of 2 types: +E and -E effect.

21. +E effect: If an electron pair shifts towards the attacking reagents, it is known
as +E effect.

22. -E effect: If an electron pair shifts away from the attacking reagents, it is
known as -E effect. It is more common in carbonyl compounds.

23. CHEMICAL PROPERTIES OF CARBONYL COMPOUNDS(ALDEHYDES & KETONES)
 Carbonyl carbons are SP2 hybridized, with the SP2 orbitals forming C overlaps
with orbitals on the oxygen and on the two carbon or hydrogen atoms. These
three bonds adopt trigonal planar geometry. The remaining unhybridized 2p
orbital on the central carbonyl carbon is perpendicular to this plane, and forms a
‘side-by-side’ p-bond with a 2p orbital on the oxygen.
 The carbon-oxygen double bond is polar: oxygen is more electronegative than
carbon, so electron density is higher on the oxygen side of the bond and lower on
the carbon side.

24.  Because the carbon is electron poor, it acts as an electrophile. So, It is a
great target for attack by an electron-rich nucleophilic group.
 Because the oxygen end of the carbonyl double bond bears a partial
negative charge, anything that can help to stabilize this charge by accepting
some of the electron density will increase the bond’s polarity and make the
carbon more electrophilic.
 So, Nucleophilic addition reactions are most common in the case of
carbonyl compounds.

25. GENERAL REACTION WITH
A NUCLEOPHILE:
REACTION WITH WATER:
REACTION WITH CYANIDE:

26. SUMMARY OF NUCLEOPHILIC ADDITION REACTIONS

27. RELATIVE REACTIVITY
Generally, aldehydes are more reactive than ketones. It can be explained on the
basis of two factors: Electronic effect and steric factors.
Electronic Effect: Ketones have alkyl substituents whereas aldehydes only have one.
Carbonyl compounds undergo reaction with nucleophiles because of the polarization
of the C=O bond.
Alkyl groups are electron donating, and so ketones have their effective partial
positive charge reduced more than aldehydes (two alkyl substituents vs. one alkyl
substituent).
(Aldehydes more reactive than ketones).

28. Steric Reason:
The electrophilic carbon is the site that the nucleophile must approach for reaction
to occur.
In ketones the two alkyl substituents create more steric hindrance than the single
substituent that aldehydes have. Therefore ketones offer more steric resistance to
nucleophilic attack.
(Aldehydes more reactive than ketones).
Therefore both factors make aldehydes more reactive than ketones.

29. OTHER REACTIONS OF CARBONYL COMPOUNDS

30. Oxophosphetane Alkene

31. Formation of Imines (Condensation Reactions)
Under appropriate conditions, primary amines (and ammonia) react with ketones or
aldehydes to generate imines.
An imine is a nitrogen analogue of a ketone (or aldehyde) with a C=N nitrogen double bond
instead of a C=O. Just as amines are nucleophilic and basic, so are imines.(Sometimes
substituted imines are referred to as Schiff's bases).
Imine formation is an example of a condensation reaction - where two molecules join together
accompanied by the expulsion of a small molecule (usually water).

32. The mechanism of imine formation starts with the addition of the amine to the carbonyl group.
Protonation of the oxyanion and deprotonation of the nitrogen cation generates an unstable
intermediate called a carbinolamine.
The carbinolamine has its oxygen protonated, and then water acts as the good leaving group.
This acid catalyzed dehydration creates the double bond, and the last step is the removal of the
proton to produce the neutral amine product.

33. CONDENSATION REACTIONS EXAMPLES

34. Formation of Acetals (Addition of Alcohols)
In a similar fashion to the formation of hydrates with water, aldehydes and ketones
form acetals through reaction with alcohols.
In the formation of an acetal, two molecules of alcohol add to the carbonyl group, and one
mole of water is eliminated.
Acetal formation only occurs with acid catalysis.

35. OXIDATION OF ALDEHYDE & KETONES
Unlike ketones, the aldehydes are oxidized to carboxylic acids in the presence of oxidants
like Chromic acid, Pot. Permanganate and Silver(I) oxide.
REDUCTION OF ALDEHYDE & KETONES
The carbonyl compounds are easily reduced by Sodium borohydride.
NaBH4 reduces ketones to secondary alcohols, and aldehydes to primary alcohols.

36. CLEMMENSEN REDUCTION
EXAMPLES:

37. WOLF KISHNER REDUCTION
EXAMPLE:

38. THIOACTEAL FORMATION

39. FRIEDEL CRAFTS ACYALTION

40. QUALITATIVE TESTS OF
CARBONYL COMPOUNDS
(ALDEHYDES & KETONES)

41. The following tests are used to identify the presence of aldehydes and
ketones:
 2,4-DNP test
 Sodium bisulfite test
The difference between ketone and aldehyde the carbonyl group present in
aldehydes can be easily oxidized to carboxylic acids whereas the carbonyl
group in ketones are not easily oxidized. This difference in reactivity is the basis
for distinction of aldehydes and ketones. They are generally distinguished by
the following tests:
 Schiff’s tests
 Fehling’s test
 Tollen’s test
 Test with chromic acid
 Sodium nitroprusside test

48. STRUCTURES & USES OF
CARBONYL COMPOUNDS
(ALDEHYDES & KETONES)

49. FORMALDEHYDE

51. PARALDEHYDE

52. ACETONE

53. CHLORAL HYDRATE

54. HEXAMINE

56. BENZALDEHYDE

57. VANILLIN
USES:
It is used in fragrance (Perfumery)
industry.
It is used to mask unpleasant odors or
tastes in livestock fodder and cleaning
products.

58. CINNAMALDEHYDE