This document summarizes a session on carboxylic acid derivatives, specifically aldehydes and ketones. It discusses the structure, nomenclature, properties, and reactivity of these compounds. Key points include that aldehydes are more reactive than ketones due to less steric hindrance, and that substituents can affect the acidity and reactivity of carboxylic acid derivatives. The document provides examples to illustrate concepts discussed.

1. 5/2/2012
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Session 22
Organic Chemistry, UNAM School of Medicine1
Carboxylic Acids &Carboxylic Acids &Carboxylic Acids &Carboxylic Acids &
Carboxylic Acid Derivatives IICarboxylic Acid Derivatives IICarboxylic Acid Derivatives IICarboxylic Acid Derivatives II
Dr L.H.A. Prins (Ph.D.)
Dept. of Pharmacy
UNAM
Learning Outcomes
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By the end of this session, the student should be able to:
Understand the importance of the carboxylic acid
derivatives, namely aldehydes & ketones
Describe the structure of aldehydes & ketones
Name aldehydes & ketones according to IUPAC system
Describe the physical properties of carboxylic acids & all
of its derivatives
Organic Chemistry, UNAM School of Medicine
Carbonyl
Compounds II
Carbonyl
Compounds II

2. 5/2/2012
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AldehydesAldehydesAldehydesAldehydes
3 Organic Chemistry, UNAM School of Medicine
Importance??Importance??Importance??Importance??
4
Many compounds found in nature have aldehyde or ketone
functional groups
Vanillin & cinnamaldehyde: Naturally occurring aldehydes
Organic Chemistry, UNAM School of Medicine

3. 5/2/2012
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Structure of aldehydesStructure of aldehydesStructure of aldehydesStructure of aldehydes
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Aldehyde (R-CHO): Carbonyl C is bonded to a H on the one side
& to an alkyl/aryl group or a H on the other side
Hybridisation structure: Refer to Session 21 (Slides 11-12)
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Structure of aldehydesStructure of aldehydesStructure of aldehydesStructure of aldehydes
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Examples:
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4. 5/2/2012
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Nomenclature of aldehydesNomenclature of aldehydesNomenclature of aldehydesNomenclature of aldehydes
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Common names:
- Derived from the common names of carboxylic acids (seeTable on
next slide)
- “ic acid” (or “oic acid”) is substituted for “aldehyde”
- Greek letters - used to give locations of substituents (as with
COOH’s & other COOH derivatives)
Examples:
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Nomenclature of aldehydesNomenclature of aldehydesNomenclature of aldehydesNomenclature of aldehydes
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Nomenclature of aldehydesNomenclature of aldehydesNomenclature of aldehydesNomenclature of aldehydes
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Systematic names (IUPAC):
- Replace the terminal “e” from the name of the parent hydrocarbon
with “al”
- Carbonyl C: Always at the end of the parent hydrocarbon,
therefore always # 1
• Remember:“Alkanal”
• Examples:
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Nomenclature of aldehydesNomenclature of aldehydesNomenclature of aldehydesNomenclature of aldehydes
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Systematic names (IUPAC):
-Aldehyde group attached to a ring - named by adding
“carbaldehyde” to the name of the cyclic compound
- C to which aldehyde group is attached is carbon “1”
• Examples:
Organic Chemistry, UNAM School of Medicine

6. 5/2/2012
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KetonesKetonesKetonesKetones
11 Organic Chemistry, UNAM School of Medicine
Importance??Importance??Importance??Importance??
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Many compounds found in nature have aldehyde or ketone
functional groups
Camphor: Ketone responsible
for characteristic sweet odour
of the camphor tree
Organic Chemistry, UNAM School of Medicine

7. 5/2/2012
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Structure of ketonesStructure of ketonesStructure of ketonesStructure of ketones
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Ketone (R-COR'): Carbonyl C is bonded to 2 carbon chains or
carbon rings
Hybridisation structure: Refer to Session 21 (Slides 11-12)
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Structure of ketonesStructure of ketonesStructure of ketonesStructure of ketones
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Examples:
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8. 5/2/2012
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Nomenclature of ketonesNomenclature of ketonesNomenclature of ketonesNomenclature of ketones
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Common names:
- Name the two alkyl groups attached to the carbonyl group
followed by the word “ketone”
- Greek letters - used to give locations of substituents (as with
COOH’s & other COOH derivatives)
Examples:
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ethyl methyl ketone
Nomenclature of ketonesNomenclature of ketonesNomenclature of ketonesNomenclature of ketones
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Common names:
- Some ketones have historical common names
- Some of these names are allowed by IUPAC
- Dimethyl ketone is always called “acetone”
-Alkyl phenyl ketones: Named as acyl group followed by suffix
“phenone”
Examples:
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9. 5/2/2012
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Nomenclature of ketonesNomenclature of ketonesNomenclature of ketonesNomenclature of ketones
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Systematic names (IUPAC):
- Replace the terminal “e” from the name of the parent hydrocarbon
with “one”
- Number chain to give carbonyl carbon smallest possible #
• Remember:“Alkanone”
• Examples:
Organic Chemistry, UNAM School of Medicine
Nomenclature of ketonesNomenclature of ketonesNomenclature of ketonesNomenclature of ketones
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Systematic names (IUPAC):
- Cyclic ketones: Carbonyl C is assumed to be at position # 1
• Examples:
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10. 5/2/2012
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Nomenclature of ketonesNomenclature of ketonesNomenclature of ketonesNomenclature of ketones
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Systematic names (IUPAC):
- Ketone as a substituent: If the ketone has a 2nd FG of higher
naming priority, the ketone oxygen is indicated by the prefix
“oxo”
• Examples:
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Physical properties of COOHPhysical properties of COOHPhysical properties of COOHPhysical properties of COOH
& COOH derivatives& COOH derivatives& COOH derivatives& COOH derivatives
20 Organic Chemistry, UNAM School of Medicine

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Boiling pointsBoiling pointsBoiling pointsBoiling points
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Carbonyl compounds have the following relative boiling points:
Bp’s of an ester, acyl chloride, ketone & aldehyde are ↓ than bp of
an alcohol with a comparable molecular weight
Reason:Alcohol molecules can form H-bonds with each other
Bp of carbonyl compounds are ↑ than bp of an ether
Reason: Result of the polar carbonyl group
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Boiling pointsBoiling pointsBoiling pointsBoiling points
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Carboxylic acids have relatively high bp’s
Reason: Form intermolecular H-bonds with each other, giving them
larger effective molecular weights (called dimer formation)
Organic Chemistry, UNAM School of Medicine

12. 5/2/2012
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Boiling pointsBoiling pointsBoiling pointsBoiling points
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Amides have the highest bp’s
Reason: Strong dipole-dipole interactions as a result of resonance
1°°°° & 2°°°° amides can also form intermolecular H-bonds
Organic Chemistry, UNAM School of Medicine
Boiling pointsBoiling pointsBoiling pointsBoiling points
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Nitriles have similar bp’s to that of an alcohol
Reason: Nitriles have strong dipole-dipole interactions
Organic Chemistry, UNAM School of Medicine

13. 5/2/2012
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Boiling pointsBoiling pointsBoiling pointsBoiling points
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Carboxylic acids,Amides & Nitriles: Summary of bp’s
Organic Chemistry, UNAM School of Medicine
SolubilitySolubilitySolubilitySolubility
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Carboxylic acid derivatives are soluble in solvents such as
ethers, chlorinated alkanes & aromatic hydrocarbons
Carbonyl compounds with fewer than 4 carbons are soluble in H2O
(corresponding to alcohols & ethers)
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14. 5/2/2012
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Substituent effects on acidity
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Substituents have an effect on acidity of carboxylic acids:
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COOH
OCH3
COOH COOH
NO2
COOH
NO2
COOH
NO2
p-methoxy benzoic acid m-nitro p-nitro o-nitro
pKa = 4.46 pKa = 4.19 pKa = 3.47 pKa = 3.41 pKa = 2.16
Substituent effects on acidity
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Substituents have an effect on acidity of carboxylic acids:
Organic Chemistry, UNAM School of Medicine
-NH2, -NHR, -NR2
-OH
-OR electron donating
-NHCOCH3
-C6H5
-R
-H
-X
-CHO, -COR
-SO3H
-COOH, -COOR electron withdrawing
-CN
-NR3
+
-NO2

15. 5/2/2012
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Reactivity of COOH derivativesReactivity of COOH derivativesReactivity of COOH derivativesReactivity of COOH derivatives
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Leaving group is an anion
The weaker the base, the better the leaving group
The better the leaving group, the more reactive the carbonyl
compound
Organic Chemistry, UNAM School of Medicine
R2 N
-
RO
-
O
RCO
-
X
-
Increasing basicity
Increasing leaving ability
Reactivity of COOH derivativesReactivity of COOH derivativesReactivity of COOH derivativesReactivity of COOH derivatives
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Halide ion - weakest base & best leaving group
Therefore: Acyl/acid halides are the most reactive toward
nucleophilic acyl substitution
Amide ion - strongest base & poorest leaving group
Therefore: Amides are the least reactive toward nucleophilic
acyl substitution
Organic Chemistry, UNAM School of Medicine

16. 5/2/2012
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Reactivity of aldehydes & ketonesReactivity of aldehydes & ketonesReactivity of aldehydes & ketonesReactivity of aldehydes & ketones
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Aldehydes – less steric hindrance
– Higher reactivity towards nucleophiles
Ketones – more steric hindrance
– lower reactivity towards nucleophiles
Organic Chemistry, UNAM School of Medicine
Thank you
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END
Organic Chemistry, UNAM School of Medicine