bahan ajar amina

7/30/2019 Bahan Ajar Amina

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Chapter Amines and Amides1. Amines

2. Naming Amines

3. Physical Properties of Amines

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AminesAmines are organic compounds in which

one or more H in ammonia, NH3, is

replaced with alkyl or aromatic groups.

H H H| | |

H

N

H CH3

N

H CH3

N

CH3ammonia

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Classification of AminesAmines are classified as primary, secondary, ortertiary.

In a primary(1) amine, one carbon group isbonded to the nitrogen atom.

Asecondary(2) amine has two carbon groups.Atertiary(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 nitrogenatom.

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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 ofamine.CH3CH2NH2 CH3NHCH3Ethylamine Dimethylamine

CH3|

CH3NCH2CH3Ethyldimethylamine

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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 longestchain is changed toamine.

The chain is numbered to locate theamine group and substituents.

NH2

|CH3CH2NH2 CH3CHCH3Ethanamine 2-Propanamine

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Naming Secondary and Tertiary Amines Each alkyl groups bonded to the N atom is

named asN-alkylgroups in front of the

amine name for the longest chain.HNCH3|

CH3CH2CH2NHCH3 CH3CHCH2CH3

N-Methyl-1-propanamine N-Methyl-2-butanamine

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Aromatic Amines The amine of benzene is named aniline.

Aniline 3-Chloroaniline N-Methylaniline

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NH CH3 NH2

Cl

NH2


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Heterocyclic Amine:

Pyridine Pyrole Quinoline Indole

N N N N

H

PyrolidinePiperidine

N

H

N

H


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NH2

NH2

C6H5NH2

(CH3)2NC2H5

CH3CH2CH2NH2

CH3NHCH

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1. Beri nama sistematis atau nama umum serta

klasifikasikan senyawa-senyawa amina di bawah

ini menjadi amina primer, sekunder atau tersier

LATIHAN

2-metil-1-butanamina

3-metil-3-pentanamina


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LATIHAN2. 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 AminesThe boiling points of amines are higher than

alkanes, but lower than alcohols of similar

mass.

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Solubility in WaterAmines with 1-5 carbon atoms are soluble in

water.

The N atom in amines forms hydrogenbonds 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 notas polar as the O-H bonds in alcohols.

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Learning CheckConsider the following compounds:

1. CH3CH2CH2NH2

2. CH3CH

2NHCH

3

3. CH3CH2CH2CH3

A. Which compound has the highest boiling point?

B. Which compound(s) is(are) soluble in water?

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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

CH3NH2 + H2O CH3NH3+ + OH

methylammonium hydroxide16

Chemical Properties of Amines


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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.

CH3

NH2 + HCl CH3

NH3+

Cl

Methylamine methylammonium

chloride

17

Copyright 2007 by Pearson

Education, Inc.

Publishing as Benjamin Cummings


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Learning CheckWrite 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

C

O

C

O

N HKOH

C

O

C

O

N K+ RCH 2X

C

O

C

O

N CH 2R

CO

C

O

N CH 2ROH

-/H 2O

RCH 2NH 2 +

CO

C

O

O

O

RCH 2X+ NH 3 RCH 2NH 2

RCH 2NH 2RCH 2X

RCH 2NHCH 2R

RCH 2NHCH 2RRCH 2X

(RCH 2)3N

(RCH 2)3NRCH 2X

(RCH 2)4N+

X

GabrielSynthesis

Alkylation

OH-

OH-

OH-


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CH3CH2CH2NH2CH3Cl

CH3CH2CH2NHCH3

n-propylaminemethyl-n-propylamine

NH22 CH3CH2Br

NEt

Et

aniline N,N-diethylaniline

H2C NH2

benzylamine

(xs) CH3I H2C N

CH3CH3

CH3 I

benzyltrimethylammonium iodide

Propanamine N-methyl-1-propanamine


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Ar H HNO3 Ar NO2[ H]

Ar NH2H2SO4


2. Reduction

NO2

1) Fe, HCl2)OH

NH2

Reduction of nitroaromatic compound


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22

Reduction of nitriles to amines

CH2C N + 2 H2Raney Ni

140CH2CH2NH2

(71%)


2. Reduction

LiAlH4

N

CH3

CCH3

O

+ LiAlH4Et2O

2)H2ON CH2CH3

CH3

1)

Reduction of amides to amines:


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CR

(R')HO + NH3(or R''NH2)

-H2O

C

R

(R')HNH(R'')

ImineH2, Ni

CHR

(R')H

NH2(R'')

C O

H

+NH3

H2, Ni

90 atm40 ~ 70

CH2NH2(89%)

(CH3)2C O + H2NCH2CH2OHH2, Ni, EtOH

95

(CH3)2CNHCH2CH2OH

Reductive amination from aldehyde or ketone


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CCH2CH3

O

propiophenone

+ CH3CH2NH2NaBH3CN

CHCH2CH3

NH

CH2CH3

1-(N-ethylamino)-1-phenylpropane

O

cyclohexanone

CH3NH2, H2/NiNHCH3

cyclohexylmethylamine

Reductive Amination Examples


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2. Reductive Amination Hofmann Rearrangement

R CO

NH 2X2

OH-/H 2O

RNH 2 CO 2+

Primary amide

R C

O

N N N+

Acyl azide

H 2ORNH 2 CO 2+ + N 2


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1. Reactions of primary alkyl amines

with nitrous acid (Diazotization)

NaNO2 + HCl1/2 H2SO4HNO2 +

NaCl

1/2 Na2SO4

Nitrosating agent:

Nitrous acid

R-NH2 + NaNO2 + 2HClR- N = N Cl

+ -+ NaCl + H2O

diazonium salt


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CH3CH2CH2NH2NaNO2,HCl

CH3CH2CH2N NCl

CH3CH2CH2 + N2 + HCl

2. Reactions of primary arylamineswith nitrous acid (Diazotization)

NH2 + NaNO2 + 2 HCl0 ~ 5 N N Cl + H2O + NaCl

Primary alkyl aminesdiazonium salt

carbocation

diazonium salt


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Flowchart Reaction

28

Primary amineDiazonium

salt

A. Sandmeyerreaction

Alkylhalide/cyanide

B. Hydrolisis Alcohol

C.Deamination

Alkane/Arene

D. Azocoupling

Azocompound


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A. The Sandmeyer reaction:

Aryl diazonium salts react with cuprous

chloride, cuprous bromide, cuprous cyanide, potassiumiodide


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:Electron-withdrawing group

B. Hydrolysis of the diazonium

group byOHAryl diazonium ion is converted to phenols

(CH3)2CH NH21. NaNO2, H2SO4, H2O

2. H2O, heat(CH3)2CH OH

Question: Design a synsthesis of

OH

Br

N2+

p-Isopropylaniline p-Isopropylphenol(73%)


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C. Deamination

Aryl diazonium salts react withhypophosphorous acid (H3PO2)


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D. Azo Coupling

Contain the -N=N- group.

Result of a couplingreaction between adiazonium salt and acoupling agent. Azo group


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Azo couplingAryl diazonium salts are weak electrophiles,they react with highly reactive aromatic

compounds, to yield azo compounds

N2+Cl + N(CH3)2

CH3COO-Na+

0H2O

N N N(CH3)2

Azo dyes

OH

N N SO3 NaOrange II


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Coupling with phenols

Benzenediazonium salt and alkaline phenol gives ayellow orange azo compound

Benzenediazonium salt and alkaline naphthalen-2-ol gives a red azo compound.


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Tartrazine


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Azo memiliki ikatan rangkap

terkonjugasi Gugus kromofor adalah gugus fungsional yang

menyerap cahaya pada daerah UV-Vis sehinggamenyebabkan senyawanya memiliki warna

Salah satu gugus kromofor adalah ikatan rangkapterkonjugasi

Maka, senyawa azo memiliki warna

Maka, azo dapat dianalisis kadarnya dengan caraspektrofotometri

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TUGAS Cari definisi, rumus umum dan contoh dari :

A. Asam amino

B. Asam lemakC. Asam hidroksi

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AlkaloidsAlkaloids are Physiologically active nitrogen-containing

compounds.

Produced by plants.

Used as stimulants, anesthetics, andantidepressants.

Often habit forming.

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CocaineCocaine Is reacted with NaOH to produce the free amine form

known as crack.

39Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin Cummings


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Caffeine

Caffeine

Is a stimulant of thecentral nervous system.

Is found in coffeebeans, tea, chocolate,and soft drinks.

Contains an imidazole

ring.

40

Copyright 2007 by Pearson Education, Inc.



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NicotineNicotine Increases the adrenaline level in the blood.

Causes addiction to tobacco.

Contains a pyrrolidine ring.

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N

CH3


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Alkaloids Related to MorphineAlkaloids 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.

42Copyright 2007 by Pearson Education, Inc. Publishing as Benjamin Cummings


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Morphine and Codeine

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Copyright 2007 by Pearson Education, Inc.



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Important Aromatic Amines

N

NN

H

N

N

NH

Purine

(Adenine, Guanine)

Pyrimidine

(Cytosine, Thymine)

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