ORGANIC CHEMISTRY REACTION SCHEME
AN OVERVIEW
ALKANES
Preparation of Alkanes
1. Hydrogenation of Alkenes
H2 + Ni, Pd or Pt
CnH2n 
 CnH2n+2
2. Reduction of Alkyl Halides
a. Hydrolysis of Grignard Reagent
dry ethyl ether
water
RX + Mg 
 RMgX 
 RH + Mg(OH)X
*Note: RMgX is the Grignard reagent, alkylmagnesium halide. The alkyl group is covalently bonded to magnesium;
and magnesium-halogen bond is ionic ie. [R:Mg]+[X]–. In the second step of the reaction, it is a displacement
reaction in which water (the stronger acid) displacing the weaker acid (R–H) from its salt (RMgX).
b. Reduction by Metal and Acid
+
Zn + H
 RH + Zn2+ + X–
RX 
Reactions of Alkanes
1. Halogenation [Free Radical Substitution]
heat, or UV
CnH2n+1H + X2 
 CnH2n+1X + HX
2. Combustion
heat
CnH2n+2 + excess O2 
 nCO2 + (n+1)H2O
3. Pyrolysis Cracking
400-600C

 H2 + smaller alkanes + alkenes
alkane 
with or w/o catalyst
ALKENES
Preparation of Alkenes
1. Dehydrohalogenation of Alkyl Halides
H
H
H
C
C
H
X
alcoholic KOH

H  OH 
reflux
H
H
H
C
C
2. Dehydration of Alcohols
H
H
H
C
C
excess conc H2SO 4 , 170 C
H 
 H
or Al2 O3 , 400 C
H+ KX + H2O
H
H
C
C
H + H2O
or H3PO4 , 200-250 C
H
OH
3. Dehalogenation of Vicinal Dihalides
H
H
H
C
C
X
X
Zn
H  H
H
H
C
C
H + ZnX2
Reactions of Alkenes
1. Addition of Hydrogen. Catalytic Hydrogenation
H2 + Ni, Pd or Pt
 CnH2n+2
CnH2n 
Heat
1
nh05
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
2. Addition of Halogens [Electrophilic Addition using bromine/ethene]
H
H
H
H
H
C
X2 /CCl4
H 

dark, room temperature
C
3. Addition of Aqueous Halogen. Formation of Halohydrin
H
H
H
H
C
X2 /H2 O
H 
 H
C
H
C
C
X
X
H
H
H + HX
C
C
X
OH
Dark, room temp
4. Addition of Hydrogen Halides
H
H
H
C
HX
 H
H 
C
5. Addition of Water. Hydration
a) Industrial Method
H
H
H
C
C
H2 O(g)


conc H3PO4
H
H
H
H
C
C
X
H
H
H
H
C
C
H
OH
H
300C, 60atm
b) Laboratory Method
H
H
H
C
C
H
conc H2 SO4


cold
H
H
H
C
C
H
OSO3H
H
H2 O, heat

 H
(hydrolysis)
6. Oxidation
a) Cold, alkaline KMnO4 Solution
H
H
H
C
C
alkaline KMnO 4

H
cold
H
b) Hot, acidic KMnO4 Solution
H
H
H
C
C
H
H
H
C
C
OH
OH

C
H
C
C
H
OH
H + H2SO4
H
H
MnO4 /H2 SO4
H

hot
H
H
O
+
O
C
H
*Note: Terminal carbons will be oxidized into carbon dioxide.
*Note: Under such oxidizing conditions, the aldehydes will be oxidized to carboxylic acid very quickly. To extract the
aldehyde only, we must use immediate distillation.
7. Combustion
ARENES
Reactions of Benzenes
1. Nitration [Electrophilic Substitution in mononitration of benzene]
NO 2
conc. HNO3


conc. H2SO4
55oC
2
nh05
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
2. Sulphonation
OSO 2H
H2 SO4 ( l )


reflux
+ H2O
3. Halogenation
X
+ X2
cold, dark


FeX3 , or AlX3
+ HX
Or Fe
4. Friedel-Crafts Alkylation
R
FeX3 , or AlX3
+ RX 

Lewis Acid
+ HX
5. Friedel-Crafts Acylation
COR
Note: acyl group
+ RCOCl / [(RCO) 2O]

FeX3 , or AlX3
O
+ HX
R
C
H
6. Hydrogenation
+ 3H 2
Ni


150C
Preparation of Alkylbenzenes
1. Attachment of Alkyl Group. Friedal-Crafts Alkylation
R
FeX3 , or AlX3
+ RX 

Lewis Acid
2. Conversion of side chain
R
+ HX
H
H
C
C
O
Zn(Hg), HCl, heat


or N2H4 , base, heat
R
+ HX
N2 + H2O
Or H2/Pd,
ethanol
*Note: This is known as the Clemmensen or Wolff-Kishner Reduction
3
nh05
ORGANIC
CHEMISTRY
RE ACTION
–
SCHEME
AN
OVERVIEW
Reactions of Alkylbenzenes
1. Hydrogenation
R
R
+ 3H 2
Ni, Pt, Pd


150C
2. Oxidation
a. Mild Oxidation
CHO
R
MnO2


oxidation
b. Strong Oxidation
R
COOH

MnO4 /H2 SO4


or acidified K 2 Cr2 O7
white crystals
3. Free Radical Aliphatic Halogenation
RCH 3
RCH 2X


X2
UV, light or heat
*Note: Reaction above is only a generic reaction. Actual position of the halogen is dependent on the stability of the
carbocation intermediate.
4. Electrophillic Aromatic Halogenation by Electrophillic Addition
R
R
R
X
X2


FeX3 , FeX5
+
X
5. Electrophillic Aromatic Nitration by Electrophillic Addition
R
R
R
NO 2
conc HNO3


conc H2 SO4
+
30oC
NO 2
6. Electrophillic Aromatic Friedal-Crafts Alkylation by Electrophillic Addition
R
R
R
R1
R1X


AlX3
+
R1
4
nh05
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
7. Electrophillic Aromatic Sulphonation by Electrophillic Addition
R
R
OVERVIEW
R
OSO 2H
H2 SO4 ( l )


+
OSO 2H
8. Electrophillic Aromatic Friedal-Crafts Acylation by Electrophillic Addition
R
R
R
COR 1
+ R1COCl / [(R1CO)2O]
+
FeX3 , or AlX3


COR 1
Alkylbenzenes clearly offers two main areas to attack by halogens: the ring and the side chain. We can
control the position of the attack simply by choosing the proper reaction conditions. Refer to Appendix for
more details.
HALOGEN DERIVATIVES
Preparation of Halogenoalkanes
1. Substitution in Alcohols
a. Using HX (suitable for 3° alcohols)
dry HX, ZnX2 (catalyst)
R–OH 

 R–X + H2O
Reflux
b. Using PX3/PX5 (suitable for 1°, 2° alcohols)
PX3 /PX 5
R–OH 
 R–X + POX3 + HX
Reflux
c.
Using SOCl2 (sulphonyl chloride)
SOCl2 , Pyridine(C5H5N)
R–OH 
 R–Cl + SO2 + HCl
Reflux
*Note: This is the best method because it is very clean. SO2 can be bubbled off and HCl, being an acid, will react
with pyridine.
2. Electrophillic Addition to Alkenes
a) Addition of Hydrogen Halides
H
H
H
C
C
HX
 H
H 
H
H
C
C
X
H
b) Addition of Halogens
H
H
H
C
C
X2 /CCl4
H 

dark, room temperature
H
H
H
H
C
C
X
X
H
3. Free Radical Substitution of Alkanes
heat, or UV
CnH2n+1H + X2 
 CnH2n+1X + HX
5
nh05
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
Reactions of Halogenoalkanes
1. Alkaline Hydrolysis of Alcohols [Nucleophilic Substitution]
aqueous KOH
R–X + OH– 
 R–OH + X–
reflux
*Note: Mechanism is SN2 for 1° halogenoalkane and SN1 for 3° halogenoalkane
2. Nitrile Synthesis
aqueous ethanol
R–X + NaCN 
 R–C≡N + NaBr
reflux
*Note: Nitriles are useful because they can be used to synthesize 1o amines and carboxylic acids.
Reduction to Amine:
LiAlH4 , dry ether
 RCH2NH2
R–C≡N 
or 2H2 , Ni, heat
Acidic Hydrolysis:
HCl ( aq )
R–C≡N 
 RCOOH + NH4+
reflux
Basic Hydrolysis:
NaOH ( aq )
R–C≡N 
 RCOO–Na+ + NH3
reflux
3. Formation of Amines
δ+
δ–
NH3
ethanol, reflux
R–X + excess conc NH3 
 RNH2 + NH4+X–
 [H3N---R---X] 
sealed tube
*Note: NH3 acts as the nucleophile and the base.
*Note: In the presence of excess RX, there will be polyalkylation of the halogenoalkane and 1°, 2°, 3° and even 4° ammonium
salt will be formed.
RX
RX
RX
RX
 RNH2 
 R2NH 
 R3N 
 R4N+X–
NH3 
4. Williamson Synthesis (Formation of Ether) Conc H SO , 140 C
R–X + R'O–Na+ 
 R–O–R' + NaX
2
4
o
*Note: The sodium or potassium alkoxide (anion of alcohol) is prepared by dissolving sodium and potassium in appropriate
alcohol. ROH + Na  RO–Na+ + ½H2
5. Dehydrohalogenation (Elimination)
H
H
H
C
C
H
X

alcoholic KOH
 H
H  OH (aq ) 
reflux
H
H
C
C
H + KX + H2O
Preparation of Halogenoarenes (Aryl Halides)
1. Electrophilic Aromatic Halogenation by Substitution
X
+ X2
cold, dark


FeX3 , or AlX3
+ HX
Reactions of Halogenoarenes
1. Industrial Hydrolysis (Replacement of Halogen Atom, difficult due to strong C–X bond)
+
X
O Na
2NaOH


350C, 150atm
+ NaX + H2O
-
+
O Na
OH

H ( aq )


+ Na+
2. Williamson Synthesis (Formation of Ether)
R–X + ArO–Na+ 
 R–O–Ar + NaX
Conc H2SO4, 140oC
6
nh05
ORGANIC
CHEMISTRY
RE ACTION
–
SCHEME
AN
OVERVIEW
HYDROXY COMPOUNDS
Preparation of Alcohols
1. Alkene Hydration. Addition of Water.
H
H
H
C
C
H
conc H2 SO4


cold
H
H
H
C
C
H
OSO3H
H2 O, heat

 H
(hydrolysis)
H
H
H
C
C
H
OH
H + H2SO4
2. Alkaline Hydrolysis of Halogenoalkanes
aqueous KOH
R–X + OH– 
 R–OH + X–
reflux
3. Reduction of Carboxylic Acids, Aldehydes and Ketones
a. Carboxylic Acids and Aldehydes are reduced to their primary alcohols.
H
R
+
C
O
+
4[H]
1. LiAlH4 (ethoxyethane), reflux 2.H /H2 0


or H2 , Ni
R
C
HO
OH
+ H2O
H
H
R
+
C
O
+
4[H]
1. LiAlH4 (ethoxyethane), reflux 2.H /H2 0


or H2 , Ni
R
H
C
OH
H
b. Ketones are reduced to their secondary alcohols.
R
R
+
C
O
+
4[H]
1. LiAlH4 (ethoxyethane), reflux 2.H /H2 0


or H2 , Ni
R1
C
OH
R1
H
*Note: Lithium aluminium hydride (or Lithium tetrahydridoaluminate(III)), LiAlH4, is one of the few reagents that can
reduce an acid to an alcohol; the initial product is an alkoxide which the alcohol is liberated by hydrolysis.
The –H ion acts as a nucleophile, and can attack the carbon atom of the carbonyl group. The intermediate then
reacts with water to give the alcohol.
OH
R
O
H3C
H3C
H2O
C
C
O
C
H
H
–
H
H
H
H
H2O
 4RCH2OH
Carboxylic Acid: 4RCOOH + 3LiAlH4  4H2 + 2LiAlO2 + (RCH2O)4AlLi 
H2O
 4R2CHOH + LiOH + Al(OH)3
Ketones: 4R2C=O + LiAlH4  (R2CHO)4AlLi 
Reactions of Alcohols
1. Substitution in Alcohols
a. Using HX (suitable for 3° alcohols)
dry HX, ZnX2 (catalyst)

 R–X + H2O
R–OH 
Reflux
b. Using PX3/PX5 (suitable for 1°, 2° alcohols)
PX3 /PX 5
R–OH 
 R–X + POX3 + HX
Reflux
c.
Using SOCl2 (sulphonyl chloride)
SOCl2 , Pyridine(C5H5N)
 R–Cl + SO2 + HCl
R–OH 
Reflux
*Note: This is the best method because it is very clean. SO2 can be bubbled off and HCl, being an acid, will react
with pyridine.
2. Reaction with Sodium/Potassium
H
H
C
O
H
H
Sodium/Potassium

H
H
C
-
+
O Na
+
1
H2
2
H
*Note: Alcohols are too weak to react with hydroxides and carbonates.
7
nh05
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
3. Oxidation to Carbonyl Compounds and Carboxylic Acids
a. Primary Alcohols are oxidized to aldehydes first, then carboxylic acids.
R
R
R
OH
K 2 Cr2 O7 /H2 SO4
K 2 Cr2 O7 /H2 SO4
C
O
C


C


immediate
or KMnO4 /H2SO4
distillation
H
H
HO
H
O
*Note: MnO2 is also a milder oxidizing agent.
b. Secondary Alcohols are oxidized to ketones.
R
R
OH
K 2 Cr2 O7 /H2 SO4
C
C


or KMnO4 /H2 SO4
R1
R1
H
c.
O
Tertiary alcohols are not readily oxidized.
4. Dehydration to Alkenes
a. Excess conc H2SO4
H
H
H
C
excess conc H2SO 4 , 170 C
H 
 H
or Al2 O3 , 400 C
C
H
H
C
C
H + H2O
or H3PO4 , 200-250 C
H
OH
b. Excess alcohol
140C
R–CH2OH + conc H2SO4 
R–CH2–O– CH2–R
excess alcohol
5. Esterification
O
R
O
R1
C
heat
(can use acid or
alkaline as catalyst)
H
OH
C
conc H2 SO4
O
+
R1
R
H2O
+
O
6. Acylation
a. Acid Chloride
R
C
+
Cl
Note: acyl group
R1

OH
R
room temperature
C
O
R1
O
+ HCl
R
O
C
O
H
b. Acid Anhydride
R
C
O
O
C
R
room temperature


+ R1 OH
R
C
O
O
R1
+
R
C
O
OH
O
H
7. Tri-Iodomethane (Iodoform) Formation
*Note: Reaction is only positive for alcohol containing a methyl group and a hydrogen atom attached to the carbon at
which the hydroxyl group is also attached.
H
CH3
H
R
C
OH
I2 , NaOH ( aq )


warm
CHI 3
CH3
a. Step 1: Oxidation of Alcohol to the corresponding carbonyl compound by iodine.
R
CH
OH
+
C
-
I2 + 2 HO
R
CH3
C
O
+ 2 H2 O
+ 2I
-
CH3
8
nh05
OH
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
b. Step 2: Further oxidation to carboxylate salt and formation of iodoform
R
C
O
-
+ 3 I2 + 4HO
R
O
+ CHI 3 + 3 I
O
+ CHI 3 + 5 I
-
+ 3 H2O
-
O
CH3
c.
C
Overall Equation:
H
-
R
C
OH + 4 I2 + 6HO
R
C
-
+ 5 H2 O
-
O
CH3
Preparations of Phenols
1. Replacement of OH– group in diazonium salts
N
+
N O
NH2
O
-
S
OH
OH
O



water, H , heat


NaNO2 , H2 SO4
Reactions of Phenols
1. Reaction with Reactive Metals (e.g. Na or Mg)
+
-
O Na
OH
+
Na
+
1
H
2 2
2. Reaction with NaOH
-
OH
+
O Na
+ NaOH
+
1
H O
2 2
*Note: Phenols have no reactions with carbonates
3. Esterifications
-
OH
+
O Na
NaOH


RCOCl

O
O
C
R
*Note: Phenols do not react with carboxylic acids but their acid chlorides to form phenyl esters.
*Note: Esterification is particularly effective in NaOH(aq) as the alkali first reacts with phenol to form phenoxide ion which is a
stronger nucleophile than phenol.
9
nh05
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
4. Halogenation
a. With bromine(aq)
OH
OH
Br
Br
+ 3HBr
3Br2 ( aq )


Br
*Note: 2,4,6-tribromophenol is a white ppt.
b. With bromine(CCl4)
OH
OH
Br2 (CCl4 )


OH
+
Br
Br
5. Nitration
a. With conc nitric acid
OH
OH
O 2N
NO 2
conc HNO3


NO 2
b. With dilute nitric acid
OH
OH
dil HNO3


OH
+
NO 2
O 2N
6. Reaction with FeCl3(aq)
*Note: This is a test for phenol. Violet complex upon adding iron(III) chloride will confirm presence of phenol. Colour may vary
depending on the substitution on the ring.
3--
O
OH
3+
Fe


Fe
6
10
nh05
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
CARBONYL COMPOUNDS
Preparation of Aldehydes
1. Oxidation of Primary Alcohols
R
OH
K 2 Cr2 O7 /H2 SO4


C
immediate
distillation
H
H
R
C
H
Preparations of Ketones
1. Oxidation of Secondary Alcohols
R
R
OH
K 2 Cr2 O7 /H2 SO4
C
C


or KMnO4 /H2 SO4
R1
R1
H
2. Oxidative Cleavage of Alkenes
R2
R3
C
R1
+ H2 O
O
R2
R3

MnO4 /H2 SO4

hot
C
H2 O
+
O
R1
R4
+
C
C
O
O
R4
Reactions of Carbonyl Compounds
1. Addition of Cyanide. Cyanohydrin formation.
[Nucleophilic Addition of Hydrogen Cyanide to Aldehyde and Ketone]
H
H
H
C
HCN, small amount of base
+ CN 
C
CN
 H
O
OH
*Note: Cyanohydrins can be hydrolysed to form 2-hydroxy acids.
Acidic Hydrolysis
R
H
C
R
CN
water, HCl (aq)



heat
H
OH
C
+ NH 4Cl
COOH
OH
Basic Hydrolysis
R
H
C
R
water, NaOH ( aq )

 H
heat
CN
OH
C
-
COO Na
+
+
NH 3
OH
*Note: Cyanohydrins can undergo reduction.
R
H
C
R
CN
LiAlH4 in dry ether

or H2 , Ni, heat
H
OH
R2
C
CH 2NH 2
OH
2. Reaction with 2,4-Dinitrophenylhydrazine (Brady’s Reagent). Condensation Reaction.
R2
C
O + H2N
NH
NO 2
C
N
NH
NO 2 +
H 2O
R1
R1
O 2N
O 2N
*Note: 2,4-dinitrophenylhydrazones formed are orange or yellow crystalline solids with characteristic melting points. They are
useful for identifying individual aldehydes and ketones.
11
nh05
ORGANIC
CHEMISTRY
RE ACTION
–
SCHEME
AN
OVERVIEW
3. Oxidation Reactions
*Note: Aldehydes are easily oxidized to carboxylic acids. Ketone are not.
a. Oxidation of Aldehydes using hot, acidified potassium dichromate(VI)
*Note: K2Cr2O7 turned from orange to green if test is positive.
R
H
R
C
OH
C
K 2 Cr2 O7 /H2 SO4


heat
O
O
O
O
K 2 Cr2 O7 /H2 SO4


heat
C
C
H
R1
R
OH
C
K 2 Cr2 O7 /H2 SO4

 No Reaction
heat
O
b. Oxidation of Aldehydes using hot, acidified potassium manganate(VII)
*Note: KMnO4 turned from purple to colourless if test is positive.
R
H
R
C
OH
C


K 2MnO4 /H2 SO4
heat
O
O
O
O
C
C
K 2MnO4 /H2 SO4


heat
H
c.
OH
Oxidation of Aliphatic Aldehydes using Fehling’s Solution (Fehling’s Test)
R
H
C
R
O
-
C
Fehling's Solution


warm
O
+
Cu 2O (s)
O
O
C
Fehling's Solution

 No Reaction
warm
H
R
R1
C
Fehling's Solution

 No Reaction
warm
O
*Note: Aliphatic aldehydes reduce the copper(II) in Fehling’s solution to the reddish-brown copper(I) oxide.
R–CHO + 2Cu2+ + 5OH–  R–COO– + Cu2O (s) + 3H2O
*Note: Methanal (strongest aldehyde reducing agent) produces metallic copper as well as copper(I) oxide.
HCHO + Cu2O + OH–  HCOO– + 2Cu (s) + H2O
d. Oxidation of Aldehydes using Tollen’s Reagent (Silver Mirror Test)
R
H
C
R
Tollen's Reagent


warm
O
O
C
-
Ag (s)
+
O
O
O
Tollen's Reagent


warm
C
C
+ Ag (s)
-
H
O
12
nh05
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
d. Oxidation of Aldehydes using Tollen’s Reagent (Silver Mirror Test) (Cont’d)
R
R1
Tollen's Reagent
C

 No Reaction
warm
O
*Note: Aldehydes redyce the Ag(I) in Tollen’s reagent to Ag, forming a silver mirror.
heat
 RCOO– + 2Ag (s) + 4NH3 + 2H2O
RCHO + 2[NH3AgNH3]+ + 3OH– 
4. Reduction Reactions
a. Reduction of Aldehydes to Primary Alcohols
LiAlH4 in dry ether
R–CHO + 2[H] 
R–CH2OH
or NaBH4 ( aq )
Ni catalyst
R–CHO + H2 
 R–CH2OH
heat
b. Reduction of Ketones to Secondary Alcohols
R
H
R1
C
+
H2
LiAlH4 in dry ether

or NaBH4 ( aq )
R
C
O
R
OH
H
R1
C
R1
+
H2
R
Ni catalyst


heat
C
O
R1
OH
5. Reaction with Alkaline Aqueous Iodine (Tri-Iodomethane (Iodoform) Formation)
H
*Note: Reaction is only positive for alcohol containing a methyl group attached to the carbon at which the carbonyl group
is also attached i.e. methyl carbonyl compounds. For aldehydes, only ethanal will form iodoform. All methyl ketones will
form iodoform.
NaOH, warm
R
C
O + CHI 3 + 3I + 3H2O
R
C
O + 3 I 2 + 4HO 

O
CH3
-
6. Chlorination using Phosphorus Pentachloride (PCl5)
*Note: Aldehydes and ketones react with phosphorus pentachloride to give geminal-dichloro (cf. vicinal) compounds. The
oxygen atom in the carbonyl group is replaced by two chlorine atoms.
CH3CHO + PCl5 
 CH3CHCl2 + POCl3
CH3COCH3 + PCl5 
 CH3CCl2CH3 + POCl3
CARBOXYLIC ACIDS & DERIVATIVES
Preparation of Carboxylic Acids
1. Oxidation
a. Oxidation of Primary Alcohols and Aldehydes
R
R
R
OH
K 2 Cr2 O7 /H2 SO4
K 2 Cr2 O7 /H2 SO4
C
O
C


C


immediate
or KMnO4 /H2SO4
distillation
H
H
HO
H
b. Oxidative Cleavage of Alkenes
H
H
C
H
H
KMnO4 /H2 SO4 , heat


C
O
C
OH
H
13
O
+
O
H
C
OH
nh05
C
CH3
O
ORGANIC
c.
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
Oxidation of an Alkylbenzene (Formation of Benzoic Acid)
O
CH3
C
+ 3[O]
OH
KMnO4/H2SO4 , heat


+ H2 O
2. Hydrolysis
a. Hydrolysis of Nitriles (R–C≡N)
Acidic Hydrolysis
HCl ( aq )
R–C≡N 
 RCOOH + NH4+
reflux
Basic Hydrolysis
NaOH ( aq )
R–C≡N 

 RCOO–Na+ + NH3
reflux
b. Hydrolysis of Esters (RCOOR’)
Acidic Hydrolysis
RCOOR’ + H2O
HCl ( aq ), reflux
RCOOH + R’OH
conc H2SO4
Basic Hydrolysis
NaOH (aq )
RCOOR’ + H2O 

 RCOO–Na+ + R’OH
reflux
+
H
 RCOOH
RCOO–Na+ 
reflux
Reactions of Carboxylic Acids
1. Salt Formation
a. Reaction with Metal
RCOOH + Na 
 RCOO–Na+ + ½H2
b. Reaction with Bases
RCOOH + NaOH 
 RCOO–Na+ + H2O
c. Reaction with Carbonates
2RCOOH + Na2CO3 
 2RCOO–Na+ + H2O + CO2
2. Esterification
O
R
O
C
R1
+
OH
C
conc H2 SO4
O
H
heat
(can use acid or
alkaline as catalyst)
R
R1
+
H2O
O
3. Conversion into Acyl Chlorides (RCOCl)
RCOOH + PCl5 
 RCOCl + POCl3 + HCl
3RCOOH + PCl3 
 3RCOCl + H3PO3
RCOOH + SOCl2 
 RCOCl + HCl + SO2
4. Reduction to Alcohols
1. LiAlH4 in dry ether
 RCH2OH + H2O
RCOOH + 4[H] 
2. H2 SO4 ( aq )
Preparation of Acyl Chlorides
1. From Carboxylic Acid
RCOOH + PCl5 
 RCOCl + POCl3 + HCl
3RCOOH + PCl3 
 3RCOCl + H3PO3
RCOOH + SOCl2 
 RCOCl + HCl + SO2
14
nh05
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
Reactions of Acyl Chlorides
1. Conversion into Acid. Hydrolysis
RCOCl + H2O 
 RCOOH + HCl
ArCOCl + H2O 
 ArCOOH + HCl
*Note: Benzoyl chloride reacts much slower than acyl chlorides because of the reduce in the positive nature of the carbonyl
carbon caused by resonance.
2. Ester Formation. Alcoholysis.
room temperature
RCOCl + R’OH 
 RCOOR’ + HCl
*Note: Reaction is slow when phenol is directly reacted with acyl chloride.
slow
 RCOOAr + HCl
RCOCl + ArOH 
*Note: Because phenol is a weaker nucleophile (lone pair of electron delocalizes into the ring), it is converted to phenoxide to
increase nucleophilic strength.
 ArO–Na+ + H2O
ArOH + NaOH 
 RCOOAr + Cl–
RCOCl + ArO– 
3. Amide Formation. Ammonolysis.
RCOCl + NH3 
 RCONH2 + HCl
RCOCl + R’NH2 
 RCONHR’ + HCl
RCOCl + R’R’’NH 
 RCONR’R’’ + HCl
4. Reduction to Aldehyde, then Alcohol
LiAlH4 in dry ether
LiAlH4 in dry ether
RCOCl 
RCHO 
RCH2OH
H2 SO4 ( aq )
Preparations of Esters
1. Condensation Reaction of Acid and Alcohol
a. Ethyl Ethanoate
O
R
O
C
R1
+
OH
C
conc H2 SO4
O
H
heat
(can use acid or
alkaline as catalyst)
R
R1
+
H2O
O
b. Phenyl Benzoate
ArOH + NaOH 
 ArO–Na+ + H2O
–
+
ArCOCl + ArO Na 
 ArCOOAr + NaCl
Reaction of Esters
1. Hydrolysis
a. Acidic Hydrolysis
RCOOR’ + H2O
HCl ( aq ), reflux
conc H2SO4
RCOOH + R’OH
b. Basic Hydrolysis
NaOH (aq )
RCOOR’ + H2O 

 RCOO–Na+ + R’OH
reflux
2. Reduction to Primary Alcohols
LiAlH4 in dry ether
RCOOR’ 
RCH2OH
H2 SO4 ( aq )
Preparation of Polyesters
1. Condensation Reaction
acid
nHOOCRCOOH + nHOR’OH 
 ( OCRCOOR’O )
reflux
15
n
+ 2nH2O
nh05
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
NITROGEN COMPOUNDS
Preparation of Amines
1. Reaction of Halides with Ammonia or Amines. Ammonolysis
δ+
δ–
NH3
ethanol, reflux
R–X + excess conc NH3 
 RNH2 + NH4+X–
 [H3N---R---X] 
sealed tube
RX
RX
RX
RX
NH3 

 RNH2 

 R2NH 

 R3N 

 R4 N+ X –
2. Reduction
a. Reduction of Amide
LiAlH4 in dry ether
RCONH2 
RNH
RCH2 2NH2
H2 / Ni or Pt
b. Reduction of Nitrile
LiAlH , dry ether
 RCH2NH2
R–C≡N 
or 2H , Ni, heat
4
2
c.
Reductive Amination
H
H
H
C
O
+ NH 3 
H
C
NH
H2 , Ni

H
or NaBH3 CN
C
NH2
imine
H
H
Reactions of Amines
1. Salt Formation
RNH2 + HCl 
 RNH3+ Cl–
RNH2 + R’COOH 
 RNH3+ –OOCR’
+
NH2
NH 3 Cl
+
HCl
-


*Note: Phenylamine is not soluble in water but dissolves in acid.
2. Formation of Amides. Acylation.
R'COCl

 R'CONHR + HCl
ArSO2 Cl

 ArSO2NHR + HCl
RNH2
RR'NH
R''COCl

 R''CONRR'  HCl
ArSO2 Cl

 ArSO2NRR'  HCl
RR'R''N
R'''COCl

 no reaction
ArSO2 Cl

 no reaction
*Note: Since HCl is formed, some of the ammonia/amine will be protonated and cannot act as a nucleophile. Hence, at least
double the amount of ammonia / amine must be used.
*Note: Acylation of 1° and 2° amines leads to the formation of substituted amides. 3° do not undergo acylation because they
do not have any replaceable H atoms.
CH3CH2NH2 + CH2COCl  CH3CH2NHCOCH3 + HCl
ArNH2 + Ar’COCl  ArNHCOAr’ + HCl
ArNH2 +RCOCl  ArNHCOR + HCl
3. Ring Substitution Reactions of Aromatic Amines
a. Halogenation
NH2
NH2
Br
+
3Br2 (aq)
Br


(s)
+ 3HBr
White ppt
Br
16
nh05
ORGANIC
CHEMISTRY
RE ACTION
–
SCHEME
AN
OVERVIEW
*Note: To get monosubstituted compounds, react phenylamine with ethanoyl chloride to reduce the ‘strongly
activating’ nature of the amino group to form phenylacetamide.
NH2
NHCOCH 3
+
CH 3COCl


*Note: NHCOCH3 is also 2,4-directing but moderately activating. Halogenation of ArNHCOCH3 will give N-(2bromophenyl)acetamide or N-(4-bromophenyl)acetamide. Reacting this with aqueous NaOH and heating will give
2-bromophenylamine or 4-bromophenylamine.
b. Nitration
NH2
NH2
O 2N
NO 2
conc HNO 3
+ conc H SO 
2
4
NO 2
*Note: The same steps as above can be taken if we want monosubstituted nitrophenylamine.
Preparations of Amides
1. Ammonolysis of Acid Derivatives
RCOCl + NH3 
 RCONH2 + HCl
RCOCl + R’NH2 
 RCONHR’ + HCl
RCOCl + R’R’’NH 
 RCONR’R’’ + HCl
2. Reaction between Amine and Acid Chloride
R'COCl

 R'CONHR + HCl
RNH2
ArSO2 Cl

 ArSO2NHR + HCl
RR'NH
R''COCl

 R''CONRR'  HCl
ArSO2 Cl

 ArSO2NRR'  HCl
Reactions of Amides
1. Acidic Hydrolysis
HCl, H2 O
RCONH2 
 R–COOH + NH4+
heat
2. Basic Hydrolysis
NaOH, H2O
RCONH2 
 R–COO– + NH3
heat
Preparations of Amino Acids
1. Hell-Volhard-Zelinsky Reaction
H
C
H
R
Br2 , PBr3


heat
COOH
H
C
Br
H
excess conc NH3


COOH
H2N
R
C
R
COOH
Reactions of Amino Acids
1. Salt Formation
a. Reaction with H+. Cationic
+H N–CH –COO–(aq) + H+(aq) 
 +H3N–CH2–COOH (aq)
3
2
–
b. Reaction with OH . Anionic
+H N–CH –COO–(aq) + OH– (aq) 
 H2N–CH2–COO– (aq) + H2O(l)
3
2
*Note: The above two equations explains the buffering capability of amino acids.
2. Acylation (Formation of Amides)
CH3COCl + H2N–CH2–COOH 
 CH3–CO–NH–CH2COOH + HCl
17
nh05
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
3. Esterification
H2N–CH2–COOH + ROH
HCl
+H
3N–CH2–COOR
+ H2O
4. Peptide Formation
*Note: A peptide is any polymer of amino acids linked by amide bonds between the amino grup of each amino acid and the
carboxyl group of the neighbouring amino acid. The –CO–NH– (amide) linkage between the amino acids is known as a
peptide bond.
H2N
CH
C
R
O
OH
+ H2N
CH
C
R1
O
OH
H2N
5. Hydrolysis of Peptides
a. Acidic Hydrolysis
H
O
H
------
C
C
R
H
------
C
R
N
C
H
R1
H2 SO4 ( aq )
 ----------- 
heat
N
C
H
R1
C
N
CH
C
R
O
H
R1
O
H
O
C
C
OH
NaOH ( aq )
 ----------- 
heat
+
OH
+
H3N
C
------
R1
H
O
C
C
R
+ H2O
H
R
b. Basic Hydrolysis
O
H
C
CH
H
-
O
+
H2N
C
------
R1
*Note: A peptide bond can be cleaved by hydrolysis in the presence of a suitable enzyme (trypsin, pepsin etc) or by
heating in acidic or alkaline medium.
18
nh05
ORGANIC
CHEMISTRY
RE ACTION
SCHEME
–
AN
OVERVIEW
APPENDIX
Halogenation of Alkylbenzenes: Ring vs Side chain
Alkylbenzenes clearly offer two main areas to attack by halogens: the ring and the side chain. We can
control the position of attack simply by choosing the proper reaction conditions.
Halogenation of alkanes requires conditions under which halogen atoms are formed, that is, high
temperature or light. Halogenation of benzene, on the other hand, involves transfer of positive halogen,
which is promoted by acid catalysts like ferric chloride (FeCl3).
heat or light
CH4 + Cl2 
 CH3Cl + HCl
Cl
FeCl3 , cold
+ Cl2 

+ HCl
We might expect, then, that the position of attack in, for example, methylbenzene would be governed by
which the attack particle is involved, and therefore by the conditions employed. This is so: if chlorine is
bubbled into boiling methylbenzene that is exposed to ultraviolet light, substitution occurs almost exclusively
in the side chain; in the absence of light and in the presence of ferric chloride, substitution occurs mostly in
the ring.
CH3
Cl●
Atom: Attacks side chain
Cl+
Ion: Attacks ring
Markovnikov’s Rule
In the ionic addition of an acid to the carbon-carbon double bond of an alkene, the hydrogen of the acid
attaches itself to the carbon atom that already holds the greater number of hydrogens.
Saytzeff’s Rule
For elimination reactions, the preferred product is the alkene with the most alkyl groups attached to the
doubly bonded carbon atoms i.e. the most substituted product.
19
nh05