Carbonyl Compounds

1
Carbonyl Compounds

• Carbonyl is trigonal-planar
• Carbon is electrophilic
• Carboxylic acids and derivatives
• Substitution reactions
• Aldehydes and ketones
• Addition reactions (mostly)

2
ACID HALIDE ANHYDRIDE THIOESTER ESTER AMI
DE NITRILE
3
ACID NOMENCLATUREIUPAC SYSTEM

• LONGEST CONTINUOUS CHAIN WITH -COOH IS
  PARENT
• DROP -e FROM PARENT NAME AND ADD -OIC
  ACID
• FOR DIACIDS, LONGEST CHAIN MUST INCLUDE
  BOTH -COOH GROUPS - KEEP -e AND ADD DIOIC
  ACID
• CARBOXY CARBON IS C1

4
IMPORTANT COMMON NAMES

• FORMIC ACID
• ACETIC ACID
• PROPIONIC ACID
• BUTYRIC ACID
• BENZOIC ACID, PHTHALIC ACID
• MALONIC ACID, ACETOACETIC ACID
• NOTE CARBON NEXT TO -COOH IS THE
  ?-CARBON, NEXT IS ?

5
SALTS OF CARBOXYLIC ACIDS

• NAME CATION FIRST
• SECOND WORD IS THE NAME OF THE ANION
• NAME CARBOXYLIC ACID
• DROP -OIC ACID
• ADD -ATE

6
NOMENCLATURE OF ACID HALIDES

• NAME THE CARBOXYLIC ACID FROM WHICH IT
  DERIVES
• DROP THE IC ACID ENDING AND ADD YL ENDING
• NAME THE HALOGEN WITH THE -IDE SUFFIX.

7
NOMENCLATURE OF ACID ANHYDRIDES

• FOR SYMMETRICAL ANHYDRIDES, NAME THE
  CORRESPONDING CARBOXYLIC ACID AND SUBSTITUTE
  THE WORD ANHYDRIDE FOR ACID
• FOR UNSYMMETRICAL ANHYDRIDES, NAME THE
  CORRESPONDING CARBOXYLIC ACIDS IN ALPHABTICAL
  ORDER AND SUBSTITUTE THE WORD ANHYDRIDE
  FOR ACID

8
ESTERS OF CARBOXYLIC ACIDS

• NAME ALKYL GROUP ATTACHED TO OXYGEN FIRST
• SECOND WORD IS THE NAME OF THE CARBOXY
  PORTION
• NAME CARBOXYLIC ACID
• DROP -OIC ACID
• ADD -ATE
• Cyclic esters are called lactones (see page 727)

9
AMIDE NOMENCLATURE

• NAME THE CARBOXYLIC ACID FROM WHICH IT IS
  DERIVED AND SUBSTITUTE THE -OIC ACID, OR
  -IC ACID ENDING WITH THE SUFFIX -AMIDE
• NAMES OF ANY ALKYL GROUPS ATTACHED TO THE
  NITROGEN PRECEDE THE NAME OF THE AMIDE
  ALONG WITH THE PREFIX N-, OR N,N-
• Cyclic amides are called lactams (see page 728)

10
NITRILE NOMENCLATURE

• NAME THE CORRESPONDING ACID
• DROP THE -OIC ACID, OR -IC ACID ENDING
  AND REPLACE IT WITH EITHER -NITRILE OR
  -ONITRILE

11
PHYSICAL PROPERTIES OF CARBOXYLIC ACIDS

• BOILING POINTS OF CARBOXYLIC ACIDS UNUSUALLY
  HIGH
• ACIDS WITH 4 - 5 CARBONS OR LESS ARE
  WATER-SOLUBLE MORE CARBONS RESULTS IN LOWER
  WATER SOLUBILITY
• SOLUBLE IN BASES BECAUSE SALTS FORM
• TURN LITMUS RED
• SMALL MOLECULAR WEIGHT ACIDS HAVE A CERTAIN
  AIR ABOUT THEM

12
PHYSICAL PROPERTIES OF CARBOXYLIC ACID SALTS

• MELTING POINTS ARE UNUSUALLY HIGH
• LOW MOLECULAR WEIGHT SALTS ARE WATER
  SOLUBLE MORE CARBONS RESULTS IN LOWER
  WATER SOLUBILITY AND MICELLE FORMATION
• INSOLUBLE IN ORGANIC SOLVENTS LIKE ETHER

13
PHYSICAL PROPERTIES OF CARBOXYLIC ACID ESTERS

• BOILING POINTS ARE LOWER THAN THOSE OF
  ACIDS
• LOW MOLECULAR WEIGHT ESTERS ARE WATER
  SOLUBLE MORE CARBONS RESULTS IN DECREASED
  WATER SOLUBILITY ... EVEN MORE THAN FOR
  ACIDS
• OFTEN HAVE FRUITY AROMAS

14
PHYSICAL PROPERTIES OF OTHER DERIVATIVES

• AMIDES HAVE UNUSUALLY HIGH MELTING POINTS /
  BOILING POINTS
• ACID CHLORIDES AND ANHYDRIDES HAVE
  RELATIVELY LOW BOILING POINTS ... USE
  CAUTION!
• NITRILES ARE VERY POLAR

15
AMIDES HAVE A HIGH BARRIER TO ROTATION
ABOUT THE C-N BOND .... THIS IS BECAUSE IT
HAS SOME CN CHARACTER.
16
RESTRICTED ROTATION IN A TRIPEPTIDE
See figure 22.6
17
Primary and secondary amides have hydrogen bond
donors tertiary do not
Applications
18
HYDROGEN BONDING IN PROTEINS
one type of protein secondary structure (see
figure 22.8)
19
SECTION OF A ??PLEATED SHEET
(See figure 22.9)
20
IR SPECTRA

• CARBOXYLIC ACIDS AND MOST OF THEIR DERIVATIVES
  HAVE CO STRETCHES
• ACIDS HAVE OH STRETCH AS WELL ... THIS
  TYPICALLY RUNS THROUGH THE CH STRETCH REGION

21
(No Transcript)
22
(No Transcript)
23
(No Transcript)
24
PROTON NMR SPECTRA

• CARBOXYLIC ACIDS HAVE THE CO2H PROTON
  UNUSUALLY FAR DOWNFIELD ... IN THE 9 -
  14.5 REGION. THIS PROTON MAY BE EXCHANGED
  FOR D IN D2O - NOT TRUE FOR ALDEHYDIC
  PROTONS

25
USING CHEMICAL SHIFTS (and integral Curves)
TO SOLVE STRUCTURES
The NMR given below is that of an ester. What is
its structure?
26
CARBON 13 NMR

• ACIDS, ACID DERIVATIVES, ALDEHYDES, AND
  KETONES HAVE CO BETWEEN 150 - 220 PPM

27
ACID HALIDE ANHYDRIDE THIO
ESTER ESTER AMIDE NITRILE
CARBOXYLIC ACID DERIVATIVES IN DECREASING ORDER
OF REACTIVITY
28
PREPARATION OF CARBOXYLIC ACIDS

• OXIDATION OF ALKENES
• OXIDATION OF PRIMARY ALCOHOLS AND ALDEHYDES
• OXIDATION OF AROMATIC ALKYL SIDE CHAINS
• OXIDATION OF METHYL KETONES
• REACTION OF ORGANOMETALLICS WITH CO2
• HYDROLYSIS OF CARBOXYLIC ACID DERIVATIVES

29
HYDROLYSIS OF CARBOXYLIC ACID DERIVATIVES
Which carboxylic acid derivative undergoes
hydrolysis the fastest?
30
PRACTICE PROBLEM
31
ACIDITY OF CARBOXYLIC ACIDS

• ELECTRON-WITHDRAWING GROUPS INCREASE ACIDITY
• LARGER VALUES OF Ka MEAN STRONGER ACIDS AS
  DO SMALLER VALUES OF pKa
• MAY BE CONVERTED TO CONJUGATE BASE BY
  REACTION WITH A STRONG BASE LIKE NaOH OR
  NaHCO3
• AT PHYSIOLOGICAL pH PRESENT AS CONJUGATE
  BASE

32
APPLICATIONS OF ACIDITY OF
CARBOXYLIC ACIDS
-THE SEPARATION OF MIXTURES .... - IMPORTANT
CONCEPT!! -QUALITATIVE ANALYSIS
33
OTHER REACTIONS OF ACIDS

• FORMATION OF ESTERS
• FISCHER ESTERIFICATION
• REACTION OF CARBOXYLATES WITH ALKYL HALIDES
• DIAZOMETHANE
• PREPARATION OF AMIDES
• REDUCTION TO ALCOHOLS
• FORMATION OF ACID CHLORIDES
• FORMATION OF ANHYDRIDES
• DECARBOXYLATION
• ?-HALOGENATION

34
FISCHER ESTERIFICATION
35
EXPERIMENTAL EVIDENCE
36
REACTION OF CARBOXYLATES WITH ALKYL HALIDES
37
DIAZOMETHANE
38
PREPARATION OF AMIDES
39
REDUCTION TO ALCOHOLS
40
(No Transcript)
41
FORMATION OF ACID CHLORIDES
42
FORMATION OF ANHYDRIDES
Notes
Acetic anhydride sometimes used when preparing
larger anhydrides.
43
WHADAYA GIT?
44
DECARBOXYLATION
45
DECARBOXYLATIONS

• RARE - MOST ACIDS DONT DO THIS
• COMMON WITH MALONIC ACID AND ITS
  DERIVATIVES
• COMMON WITH
• ?-KETOACIDS, ??CARBONYL ACIDS, DERIVATIVES OF
  CARBONIC ACID
• OFTEN PART OF MULTISTEP SYNTHESES
  (ACETOACETIC ACID SYNTHESIS AND MALONIC
  ESTER SYNTHESIS)
• IMPORTANT IN BIOCHEMISTRY (DECARBOXYLATION OF
  PYRUVATE pages 1110-1111 and 1152-1153 IN
  THE FERMENTATION OF GLUCOSE)

46
?-HALOGENATION
Catalytic amount
HELL-VOLHARD-ZELINSKY REACTION COVERED
IN CHAPTER 18
47
REACTIONS OF ACID DERIVATIVES

• INVOLVE NUCLEOPHILIC ACYL SUBSTITUTION
  REACTIONS
• TYPICALLY INVOLVE THE TRANSFORMATION OF A
  MORE-REACTIVE DERIVATIVE INTO A LESS-REACTIVE
  ONE

48
ACID HALIDES

• ACID CHLORIDES ARE MOST COMMON

49
FORMATION OF ACID CHLORIDES
50
OTHER REACTIONS OF ACID HALIDES

• CONVERSION TO ANHYDRIDES (BEST METHOD FOR
  PREPARING MIXED ANHYDRIDES)
• CONVERSION TO ESTERS
• CONVERSION TO CARBOXYLIC ACIDS (TYPICALLY AN
  UNWANTED REACTION)
• CONVERSION TO AMIDES
• ALL FOLLOW SIMILAR MECHANISM

51
REACTIONS OF ACID ANHYDRIDES

• CONVERSION TO ESTERS
• CONVERSION TO CARBOXYLIC ACIDS (TYPICALLY AN
  UNWANTED REACTION)
• CONVERSION TO AMIDES
• ALL FOLLOW SIMILAR MECHANISM

52
ESTERS

• TRANSESTERIFICATION
• HYDROLYSIS
• CONVERSION TO AMIDES
• IMPORTANT COMPOUNDS
• WAXES
• FATS
• PHOSPHOLIPIDS

53
HYDROLYSIS OF ESTERS
54
EXPERIMENTAL EVIDENCE
55
SAPONIFICATION OF ESTERS
56
STRUCTURE OF A WAX
57
STRUCTURE OF A FAT OR OIL
58
STRUCTURE OF A FAT OR OIL
STRUCTURE OF A FATTY ACID
59
STRUCTURE OF AN UNSATURATED FATTY ACID
60
(No Transcript)
61
(No Transcript)
62
MICELLE STRUCTURE
63
DAWN LIFTS GREASE OUT OF YOUR WAY
SOAPS ARE SURFACTANTS
64
A SYNTHETIC DETERGENT
65
BILE SALTS - AID IN DIGESTION OF FATS
AND OILS IN SMALL INTESTINE
66
PHOSPHOLIPIDS
IMPORTANT CONSTITUENT OF CELL MEMBRANES
(1170-1173)
67
REDUCTION OF ACID DERIVATIVES
68
REDUCTION OF AMIDES AND NITRILES
69
ACID CHLORIDES REDUCTION TO ALDEHYDES
70
ESTER / NITRILE REDUCTION TO ALDEHYDES
71
REACTIONS OF ACID CHLORIDES AND ESTERS WITH
ORGANOMETALLICS
THE REACTION SO NICE, IT HAPPENS
TWICE!! NOTE ESTERS GENERALLY REACT TWICE
- NOT A GOOD WAY TO PREPARE A KETONE.
72
REACTIONS OF CARBOXYLIC ACIDS WITH
ORGANOMETALLICS
ORGANOLITHIUM REAGENTS ARE MORE REACTIVE
THAN GRIGNARD REAGENTS
73
REACTIONS OF NITRILES WITH ORGANOMETALLICS
74
PREPARATION OF NITRILES

• NUCLEOPHILIC SUBSTITUTION OF CYANIDE ANION
  ON ALKYL HALIDES AND SULFONATE ESTERS
• CYANOHYDRIN FORMATION FROM ALDEHYDES AND
  KETONES
• DEHYDRATION OF AMIDES

75
NUCLEOPHILIC SUBSTITUTION
76
ADDITIONS OF CYANIDE TO ALDEHYDES AND
KETONES
77
DEHYDRATION OF AMIDES
78
The Gabriel Synthesis of Amines imide