Bahan Ajar Amina

Chapter Amines and Amides
1. Amines 2. Naming Amines 3. Physical Properties of Amines
Amines
Amines are organic compounds in which one or more H in ammonia, NH3, is replaced with alkyl or aromatic groups.
H | HNH ammonia
H H | | CH3NH CH3NCH3
Classification of Amines
Amines are classified as primary, secondary, or tertiary. In a primary (1) amine, one carbon group is bonded to the nitrogen atom. A secondary (2) amine has two carbon groups. A tertiary (3) amine has three carbon groups. H CH3 CH3 | | | CH3NH CH3NH CH3NCH3 1 2 3
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Models of Amines
The three-dimensional models show the shapes of amine molecules with one or more alkyl groups bonded to the nitrogen atom.
Common Names of Amines

Simple amines are named as alkylamines. The alkyl groups bonded to the N atom are listed in alphabetical order in front of amine.
CH3CH2NH2 Ethylamine
CH3NHCH3 Dimethylamine
CH3 | CH3NCH2CH3 Ethyldimethylamine

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IUPAC Names of Amines

In the IUPAC system, amines are named as alkanamines. The e in the alkane name of the longest chain is changed to amine. The chain is numbered to locate the amine group and substituents. NH2 | CH3CH2NH2 CH3CHCH3 Ethanamine 2-Propanamine
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Naming Secondary and Tertiary Amines

Each alkyl groups bonded to the N atom is named as N-alkyl groups in front of the amine name for the longest chain. HNCH3 | CH3CH2CH2NHCH3 CH3CHCH2CH3
N-Methyl-1-propanamine butanamine N-Methyl-2-
Aromatic Amines
The amine of benzene is named aniline.
NH2 NH2 NH CH3
Cl
Aniline
3-Chloroaniline
N-Methylaniline
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Heterocyclic Amine:
N
Pyridine
N
Pyrole
N
Quinoline
N
Indole
N H
Pyrolidine
N H
Piperidine
LATIHAN
1. Beri nama sistematis atau nama umum serta klasifikasikan senyawa-senyawa amina di bawah ini menjadi amina primer, sekunder atau tersier
CH3CH2CH2NH2 CH3NHCH3 C6H5NH2 (CH3)2NC2H5
NH2
NH2
2-metil-1-butanamina
3-metil-3-pentanamina
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LATIHAN
2. Tuliskan struktur senyawa amina di bawah ini: a. Isopropilamina b. 3-pentanamina c. Siklopentanamina d. Fenilamina e. 2-metil-sikloheksanamina
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Physical Properties of Amines

The boiling points of amines are higher than alkanes, but lower than alcohols of similar mass.
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Solubility in Water
Amines with 1-5 carbon atoms are soluble in water. The N atom in amines forms hydrogen bonds with the polar O-H bond in water.
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Hydrogen Bonding for Amines

The polar N-H bond provides hydrogen bonding in 1and 2 amines, but not 3. However, the N-H bonds in amines are not as polar as the O-H bonds in alcohols.
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Learning Check
Consider the following compounds: 1. CH3CH2CH2NH2 2. CH3CH2NHCH3 3. CH3CH2CH2CH3
A. Which compound has the highest boiling point? B. Which compound(s) is(are) soluble in water?
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Chemical Properties of Amines

Amines are Bronsted-Lowry bases that attract a H+ from H2O to the N atom. Weak bases in water.
NH3 + H2O NH4+ + OH ammonium hydroxide CH3NH3+ + OH methylammonium hydroxide
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CH3NH2 + H2O
Chemical Properties of Amines

An amine salt Forms when an amine is neutralized by acid. Is named by replacing the amine part of the name with ammonium followed by the name of the negative ion.
CH3NH2 + HCl Methylamine CH3NH3+Cl methylammonium chloride
Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin Cummings
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Learning Check
Write the equation for ethylamine when it reacts with each of the following: 1. + H2O
2. + HCl
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Preparation of amines 1. Nucleophilic Substitution

O C N H C O KOH C O O C N C O
OH-
O C N K+ RCH 2 X
O C N CH 2 R C O O
Gabriel Synthesis
CH 2 R
OH /H 2 O
C O RCH 2 NH 2 + C O O
RCH 2 X + NH 3 RCH 2 NH 2
OH-
RCH 2 NH 2 RCH 2 NHCH 2 R

OH-
Alkylation
(RCH 2 )3 N
RCH 2 X RCH 2 X (RCH 2 )3 N + X
RCH 2 NHCH 2 R
RCH 2 X
(RCH 2 )4 N
CH3CH2CH2NH2 n -propylamine Propanamine
CH3Cl
CH3CH2CH2NHCH3 methyln-propylamine N-methyl-1-propanamine
NH2 aniline
2 CH3CH2Br
Et N Et N,N-diethylaniline
(xs) CH3I H2 C NH2 benzylamine
H2 CH3 C N CH3 CH3 I benzyltrimethylammonium iodide
Preparation of amines 2. Reduction

Reduction of nitroaromatic compound
Ar
HNO3 H H2SO4
Ar NO2
NH2
[ H]
Ar NH2
NO2
1) Fe, HCl 2) OH
Preparation of amines 2. Reduction

Reduction of nitriles to amines
CH2C
N + 2 H2
LiAlH4
Raney Ni 140
CH2CH2NH2
(71%)
Reduction of amides to amines:
O N CCH3 + LiAlH41) Et2O CH3

2) H2O
N CH2CH3 CH3
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Reductive amination from aldehyde or ketone
R (R')H
C O + NH3(or R''NH2)
H2, Ni
-H2O
R (R')H
C NH(R'')
R CH NH2(R'') (R')H
Imine
H C O + NH3
H2, Ni 90 atm 40 ~ 70
H2, Ni, EtOH 95
CH2NH2
(89%)
(CH3)2CNHCH2CH2OH
(CH3)2C O + H2NCH2CH2OH
Reductive Amination Examples

O CCH2CH3 + CH3CH2NH2 propiophenone NaBH3CN CH2CH3 NH CHCH2CH3
1-(N-ethylamino)-1-phenylpropane
CH3NH2, H2/Ni
NHCH3
cyclohexanone
cyclohexylmethylamine
Preparation of amines 2. Reductive Amination

Hofmann Rearrangement
R C NH O
Primary amide X2
2
OH /H 2O
RNH
+ CO 2
+ R C N N N O
Acyl azide
H 2O
RNH
+ CO 2
+ N2
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1. Reactions of primary alkyl amines with nitrous acid (Diazotization)

Nitrosating agent:
HCl NaNO2 + 1/2 H 2SO4
HNO2 + NaCl 1/2 Na2SO4

Nitrous acid + R- N = N Cl + NaCl + H2O diazonium salt
R-NH2 + NaNO2
+ 2HCl
CH3CH2CH2NH2
Primary alkyl amines
NaNO2, HCl
CH3CH2CH2 N
diazonium salt
NCl
CH3CH2CH2 + N2 + HCl
carbocation
2. Reactions of primary arylamines with nitrous acid (Diazotization)

NH2 + NaNO2 + 2 HCl
0 ~ 5
N Cl + H2O + NaCl
diazonium salt
Flowchart Reaction
A. Sandmeyer reaction B. Hydrolisis Primary amine Diazonium salt C. Deamination D. Azo coupling Alkyl halide/cyanide Alcohol
Alkane/Arene Azo compound
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A. The Sandmeyer reaction:

Aryl diazonium salts react with cuprous chloride, cuprous bromide, cuprous cyanide, potassium iodide
B. Hydrolysis of the diazonium group by OH

Aryl diazonium ion is converted to phenols
(CH3)2CH 1. NaNO2, H2SO4, H2O (CH3)2CH NH2 2. H2O, heat OH
p-Isopropylaniline
p-Isopropylphenol
(73%)
+ N2 :Electron-withdrawing group
OH
Question: Design a synsthesis of
Br
C. Deamination
Aryl diazonium salts react with hypophosphorous acid (H3PO2)
D. Azo Coupling
Contain the -N=N- group. Result of a coupling
reaction between a diazonium salt and a coupling agent.
Azo group
Azo coupling
Aryl diazonium salts are weak electrophiles, they react with highly reactive aromatic compounds, to yield azo compounds
+ CH3COO -Na+ 0 H2O
N2 Cl +
N(CH3)2
N N
N(CH3)2
Azo dyes
Orange II
N N OH
SO3 Na
Coupling with phenols

Benzenediazonium salt and alkaline phenol gives a yellow orange azo compound
Benzenediazonium salt and alkaline naphthalen2-ol gives a red azo compound.
Tartrazine
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Azo memiliki ikatan rangkap terkonjugasi

Gugus kromofor adalah gugus fungsional yang
menyerap cahaya pada daerah UV-Vis sehingga menyebabkan senyawanya memiliki warna Salah satu gugus kromofor adalah ikatan rangkap terkonjugasi Maka, senyawa azo memiliki warna Maka, azo dapat dianalisis kadarnya dengan cara spektrofotometri
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TUGAS
Cari definisi, rumus umum dan contoh dari :
A. Asam amino B. Asam lemak C. Asam hidroksi
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Alkaloids
Alkaloids are Physiologically active nitrogen-containing compounds. Produced by plants. Used as stimulants, anesthetics, and antidepressants. Often habit forming.
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Cocaine
Cocaine Is reacted with NaOH to produce the free amine form known as crack.
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Caffeine
Caffeine Is a stimulant of the central nervous system. Is found in coffee beans, tea, chocolate, and soft drinks. Contains an imidazole ring.
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Nicotine
Nicotine Increases the adrenaline level in the blood. Causes addiction to tobacco. Contains a pyrrolidine ring.
N CH3
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Alkaloids Related to Morphine

Alkaloids Such as morphine and codeine are produced by the poppy. Have been used for centuries as painkillers. Such as heroin and codeine are modifications of morphine.
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Morphine and Codeine
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Important Aromatic Amines

N N H
N N
N H
Purine (Adenine, Guanine) A, G
Pyrimidine
(Cytosine, Thymine)
C, T

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Chapter Amines and Amides

1. Amines 2. Naming Amines 3. Physical Properties of Amines

Common Names of Amines

CH3 | CH3NCH2CH3 Ethyldimethylamine

IUPAC Names of Amines

Naming Secondary and Tertiary Amines

Physical Properties of Amines

Hydrogen Bonding for Amines

Chemical Properties of Amines

Chemical Properties of Amines

Preparation of amines 1. Nucleophilic Substitution

RCH 2 NH 2 RCH 2 NHCH 2 R

RCH 2 X RCH 2 X (RCH 2 )3 N + X

CH3CH2CH2NH2 n -propylamine Propanamine

CH3CH2CH2NHCH3 methyln-propylamine N-methyl-1-propanamine

(xs) CH3I H2 C NH2 benzylamine

H2 CH3 C N CH3 CH3 I benzyltrimethylammonium iodide

Preparation of amines 2. Reduction

Preparation of amines 2. Reduction

Reduction of amides to amines:

O N CCH3 + LiAlH41) Et2O CH3

Reductive amination from aldehyde or ketone

Reductive Amination Examples

Preparation of amines 2. Reductive Amination

1. Reactions of primary alkyl amines with nitrous acid (Diazotization)

HCl NaNO2 + 1/2 H 2SO4

HNO2 + NaCl 1/2 Na2SO4

2. Reactions of primary arylamines with nitrous acid (Diazotization)

Alkane/Arene Azo compound

A. The Sandmeyer reaction:

B. Hydrolysis of the diazonium group by OH

Question: Design a synsthesis of

reaction between a diazonium salt and a coupling agent.

Coupling with phenols

Benzenediazonium salt and alkaline naphthalen2-ol gives a red azo compound.

Azo memiliki ikatan rangkap terkonjugasi

A. Asam amino B. Asam lemak C. Asam hidroksi

Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin Cummings

Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin Cummings

Alkaloids Related to Morphine

Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin Cummings

Morphine and Codeine

Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin Cummings

Important Aromatic Amines

Purine (Adenine, Guanine) A, G

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