Aldehydes, Ketones and Carboxylic Acids Notes
Aldehydes, Ketones and Carboxylic Acids Notes
Aldehydes, Ketones and Carboxylic Acids Notes
Carboxyl
Group
1. O3
2. Zn/H2O
3. By hydration of alkynes:
4. From acyl chloride (acid chloride)
Rosenmund reduction
5. From nitriles and esters
Stephen reaction
1. SnCl2 + HCl
CH3 – CN CH3 – CHO
2. H 2O
Nitriles reduced by (DIBAL-H)
Diisobutylaluminium Hydride
Esters reduced by (DIBAL-H)
6. From Hydrocarbons
1. CrO2Cl2 / CS2
2. H 2O
1. CrO3 + Anhydride
2. H 2O
7. By side chain chlorination
8. By Gatterman – Koch reaction
Preparation of Ketone
1. By oxidation of alcohols
PCC / CrO3
CH3 – CH – CH3 CH3 – C – CH3
| ||
OH O
2. Ozonolysis
1. O3
2. Zn + H2O
3. From acyl chlorides
Oxidation
Aldehydes Carboxylic Acids
Oxidation Oxidation
CH3 – CH2 – OH CH3 – CHO CH3COOH
2. From alkylbenzenes
KMnO4 / H+
a) Mechanism:
H+
Step 1 Step 2
Slow Fast
b.) Reactivity
O O O CH3
|| || || |
CH3 – C – H > CH3 – C – CH3 > CH3 – C – C – CH3
|
CH3
Reactivity 1
Hindrance
Example
c.) Addition of Grignard reagents:
Two Steps:
d.) Reaction with ammonia and its derivatives
Ammonia Imine
Amine Substituted imine
(Schiff’s base)
Hydroxylamine Oxime
Hydrazine Hydrazone
Phenylhydrazine Phenylhydrazone
Semicarbazide Semicarbazone
2. Reduction to hydrocarbons:
O
||
Zn-Hg
CH3 – C – H HCl
CH3 – CH2 – H
O
|| Zn-Hg
CH3 – C – CH3 HCl
CH3 – CH2 – CH3
b.) Wolff-Kishner reduction
O
|| 1. NH2 – NH2 / KOH
CH3 – C – H CH3 – CH2 – H
2. Ethylene Glycol
O
|| 1. NH2 – NH2 / KOH
CH3 – C – CH3 CH3 – CH2 – CH3
2. Ethylene Glycol
3. Reduction to alcohols:
H2
Ni/Pd/Pt
CH3 – CH2 – OH Catalytic Hydrogenation
NaBH4
CH3 – CHO CH3 – CH2 – OH
Aldehyde
LiAlH4
CH3 – CH2 – OH
OH
H2
|
Ni/Pd/Pt CH3 – CH2 – CH3
O OH
|| |
NaBH4
CH3 – C – CH3 CH3 – CH2 – CH3
Ketone
OH
|
LiAlH4
CH3 – CH2 – CH3
4. Tollens’ test:
Oxidation
Oxidation
Aldol
8. Cross-Aldol Condensation
Dil. NaOH
CH3 – CH=O + CH2 – CHO
|
CH3
1. Ethanal + Ethanal
2. Propanal + Propanal
4. Propanal + Ethanal
Reactant- no α-hydrogen
Acidity
< <
OCH3 NO2