Chapter 19. Amines ( 胺）19.1 Nomenclature

In common nomenclature most primary amines are named as alkylamines. In systematic nomenclature they are named by adding the suffix –amine to the name of the chain or ring system to which the NH2 group is attached with elision

of the final ePrimary Amines;²®°·

CH3NH2 CH3CH2NH2 CH3CH2CH2NH2

Methylamine(methanamine)

Ethylamine(ethanamine)

Propylamine(Propanamine)

Common name;IUPAC name;

¼×°· ÒÒ°· ±û°·

Primary Amines ( 伯胺） ;

NH2

Butylamine(Butanamine)

Cyclohexylamine(cyclohexanamine)

CH3CH2CH2CH2NH2

Common name;IUPAC name;

CH3CHCH2NH2

CH3

Isobutylamine(2-methyl-1-propanamine)

¶¡°· Ò춡°· »·¼º»ù°·

NHCH3

Ethylmethylamine(N-methylethanamine) Cyclohexylmethylamine

(N-methylcyclohexanamine)

CH3NHCH2CH3

Common name;IUPAC name;

(CH3CH2)2NH

Diethylamine(N-ethylethanamine)

¼×ÒÒ°· ¶þÒÒ°· N-¼×»ù»·¼º»ù°·

Secondary Amines;ÖÙ°·

Tertiary Amines ( 叔胺）

Trimethylamine(N,N-Dimethylmethanamine)

Ethylmethylpropylamine(N-ethyl-N-methyl-1-propanamine)

(CH3CH2)3N

Triethylamine(N,N-diethylethanamine)

Èý¼×°· ÈýÒÒ°· N-¼×»ù-N-ÒÒ»ù±û°·

(CH3)3N CH3NCH2CH2CH3

CH2CH3

In the IUPAC system, the substituent-NH2 is called the amino group.

H2NCH2CH2OH H2NCH2CH2COOH

2-Aminoethanol 3-Aminopropanoic acid

2-°±»ùÒÒ´¼ 3-°±»ù±ûËá

19.1A Arylamines （芳胺）

NH2 NHCH3

NH2

CH3

N(CH3)2

Aniline N-Methylaniline(N-methylbenzenamine)

P-Toluidine(4-methylbenzenamine)

N,N-Dimethylaniline(N,N-Dimethylbenzenamine)

(±½°·£© (N-¼×»ù±½°·£© (N,N-¶þ¼×»ù±½°·£©

(Benzeneamine)

(4-¼×»ù±½°·£©

Which arylamines are primary amines, secondary amines, tertiary amines?

19.1B Heterocyclic amines （杂环胺）

The important heterocyclic amines all have common names.

Pyrrole

(ßÁ¿©£© (ßÁßò£© (ßäßò£© (ßÅßᣩ

NH N

H

N

Pyrazole

N

NH

Imidazole

NH

Indole

Pyridine

(ßÁण© (ßÕຣ© (ßäण©

Pyridazine Pyrimidine

N N

N

1

2

3

4

1

2

3

4

N

N

1

2

3

4

Piperidine(ßßण© (ËÄÇâßÁ¿©£© (àÑßø£©

Pyrrolidine Purine

NH 1

2

3

4

N

N 1

2

34N

H

S

N

N

NH

567

8

9

1

2

3

Thiazole£¨àçßò£©

(à­ßø£©Quinoline

N

N

Isoquinoline

(Òìà­ßø£©

19.2 Physical properties and structure of amines

19.2A Physical properties

Amines are moderately polar substances; they have boiling points that are higher than those of alkanes but generally lower than those of alco

hols of comparable molecular weight.Primary Amines;

CH3CH2NH2Ethylamine

Structure bp (oC)

17 oC

Secondary Amines;

Dimethylamine (CH3)2NH 7 oCDiethylamine (CH3CH2)2NH 56 oC

Tertiary Amines;

Trimethylamine (CH3)3N 2.9 oC

Hydrogen-Bonding

Hydrogen-BondingHydrogen-Bonding

No hydrogen-bonding

Boiling point is low

19.2B Structure of aminesThe Nitrogen atom of most amines is like that of ammonia; it is approximately sp3 hybridized. The three alkyl groups (or hydrogen atoms) occupy corners of a tetrahedron; the sp3 orbital containing the unshared electron pair is directed toward the other corner. We describe the geometry of the amine by the location of the atoms as

being trigonal pyramidal.

N

R'R''

R'''

SP3 hybridized

Structure of an amine

1£©­ÓÉÓÚµªÉÏÓй¶Եç×Ó£¬°·ÏÔ¼îÐÔ¡£

2£©­°·Àà¿É×÷ΪÇ׺ËÊÔ¼Á¡£

If the alkyl groups of a tertiary amine are all different the amine will be chiral. There will be two enantiomeric forms of the tertiary amine. In practice, however, resolution is usually impossible b

ecause the enantiomers interconvert rapidly.

N

R'

R''

R'''

NR''

R'

R'''

Intercomversion of amine enantiomersÊå°·¶ÔÓ³ÌåÏ໥ת»»£¬ÄÑÒÔ²ð·Ö¡£

6 kcal mol-1

Ammonium salts cannot undergo inversion because they do not have an unshared pair. Therefore, those quaternary ammonium salts ( 季胺盐） with four different groups are chiral and can be resolved into separate (rel

atively stable) enantiomers.

N

R'

R''

R'''

NR''

R'

R'''

Quaternary ammonium salts such as these can be resolved

¼¾°·ÑζÔÓ³Ìå²»ÄÜÏ໥ת»»£¬¿ÉÒÔ²ð·Ö³Éµ¥¸ö¶ÔÓ³Ìå¡£

R'''' R''''+

X-

+

X-

19.3 Basicity of amines( 胺的碱性） : Amine salts （胺

盐）Amines are relatively weak bases. They are stronger bases than water but are far weaker bases than hydroxide ions (OH-), alkoxide ions

(RO-), and carbanions (C-).RNH2 + H2O RNH3 + OH-

+

Kb =[RNH3] [OH-]

[RNH2]

pKb = - log Kb Kb pKb ¼îÐÔBasicity

pKb

NH2

NH3 CH3NH2 CH3CH2NH2

9.42 4.74 3.36 3.25

¼îÐÔÔöÇ¿Explain;NH2 p- conjugateÓÉÓÚ

¹²éʹµªÉϵç×ÓÔÆÏò±½»·Æ«ÒÆ£¬

CH3 NH2ÓÉÓÚ¼×»ùÊÇÍƵç×Ó»ù£¬Í¨¹ý¼×»ùÓÕµ¼Ð§Ó¦£¬

ʹµªÉϵç×ÓÔÆÃܶÈÉý¸ß£¬½ÓÊÜÖÊ×ÓÄÜÁ¦ÔöÇ¿£¬¼îÐÔÔöÇ¿¡£

½µµÍÁ˵ªÉϵç×ÓÔÆÃܶȣ¬¼îÐÔ¼õÈõ¡£

The gas phase the basicities of the following amines increase with inc

reasing methyl substitution:

ÓÉÓÚ¼×»ùÊÇÍƵç×Ó»ù£¬Í¨¹ý¼×»ùÓÕµ¼Ð§Ó¦£¬

ʹµªÉϵç×ÓÔÆÃܶÈÉý¸ß£¬½ÓÊÜÖÊ×ÓÄÜÁ¦ÔöÇ¿£¬¼îÐÔÔöÇ¿¡£

CH3 N CH3

CH3

CH3HN CH3 CH3 NH3

NH2

ÓÉÓÚÔÚÈÜÒºÖУ¬

ʹµªÉϽÓÊÜÖÊ×ÓÄÜÁ¦¼õÈõ£¬¼îÐÔ¼õÈõ¡£

CH3 N CH3

CH3

CH3HN CH3 CH3 NH3NH2

Èý¼×°·ÓÉÓÚ¼×»ùµÄ¿Õ¼äÕÏ°­Ð§Ó¦£¬

The tertiary amine less basic than primary and secondary amines in aqueous solution. However, the electron-releasing effect does make the tertiary amine more basic than ammonia.

The reason for this;

This is not the order of basicity of these amines in aqueous solution, however. In aqueous solution the order is:

19.3A Basicity of arylamines（芳香胺的碱性）

pKb 9.42 8.92 3.36

¼îÐÔÔöÇ¿

NH2 NH2H3C NH

p- conjugate effect No p- conjugate effect

+I inductive effect

p- conjugate effect

19.3C Aminium salts and quaternary ammonium salts

( 胺盐和季胺盐）When primary, secondary, and tertiary amines act as bases and react with acids, they form compounds called aminium salts.

CH3CH2NH2 + HCl CH3CH2NH3Cl-+

(CH3CH2)2NH + HCl (CH3CH2)2NH2Cl-+H2O

H2O

(CH3CH2)3N + HI (CH3CH2)3NH l-+H2O

Triethylaminium iodide

Diethylaminium chloride

Ethylaminium chloride

(an amine salt)

When the central nitrogen atom of a compound is positively charged but is not attached to a hydrogen atom the compound is called

a quaterary ammonium salt.

CH3CH2+

N CH2CH3

CH2CH3

CH2CH3

Br-

Tetraethylammonium bromide(a quaternary ammonium salt)

(CH3CH2)4N+Br-

Quaterary ammonium hydroxides( 季胺碱）

Quaternary ammonium hydroxides, however, are strong bases. As solids, or in solution, they consist entirely of quaternary ammonium cations (R4N+) and hydroxide ions (OH-); they are, therefore, strong bases---as strong as sodium or p

otassium hydroxide.

CH3CH2+

N CH2CH3

CH2CH3

CH2CH3

OH-

Tetraethylammonium hydroxide(a quaternary ammonium hydroxide)

(CH3CH2)4N+OH-

(CH3CH2)4N+OH- + HCl (CH3CH2)4N+Cl- + H2O

19.3D Amines as resolving agents( 胺作为拆分试剂）

OHH

COOH

C6H5

HHO

COOH

C6H5

R- S-

+ HC6H5

NH2

CH3R- Amine

OHH

COO-

C6H5

HC6H5

NH3

CH3

R- AmineR-

+

(R, R)-salt

HHO

COO-

C6H5

S-

HC6H5

NH3

CH3

R- Amine

+

(S, R)-salt

HCl, H2O HCl, H2O

OHH

COOH

C6H5

R-

HHO

COOH

C6H5

S-

Racemic (R,S)-acid

19.4 Some biologically important amines

HO

HO

CH

OH

H2C NHR

R = CH3

R = H

Adrenaline

Noradrenaline

n.[Éú»¯]ÉöÉÏÏÙËØ

n.[Ò©]È¥¼×ÉöÉÏÏÙËØ

NH2

CH3

Amphetamine(Benzedrine)

n.[Ò©]°² ·ÇËûÃ÷

NH

CH2CH2NH2

HO

Serotonin n.º¬ ÓÚѪҺÖеÄ̧´ ºÏ °·

N

N

CH3

H

Nicotine n.Ñ̼Äá¹Å¶¡

N

Nicotinic acid

COOH

n. ÑÌËᣬÄá¿ËËá

H3CO

H3CO

H3CO

CH2CH2NH2

Mescaline n.ø˹¿¨ Áé(Ò»ÖÖÖȟÁ)

N

Pyridoxine

CH2OH

CH2OH

HO

H3C

(Vitamin B6

n.[Éú»¯]άÉúËØB6

RO

O

H

NCH3

HO

H

R = H, Morphine n.Âð·È

n.[Ò©]¿É́ ý Òò(×ÔѻƬÖÐÌáÈ¡µÄ¼îÖÊ),

R = CH3, Codeine

ÓÃÒÔÕòÍ´ ,Õò¿È,´ßÃßµÈ

H3CO

HO

H

N

H

H

(-) - Quinine n.¿üÄþ, ¿üÄþ»¯ºÏ Îï (ÈçÀïÁòËá¿üÄþ)

N

NH3C

N

S

H3C

CH2CH2OH+

Cl-

NH2

Thiamine chloride

(Vitamin B1) n. άÉúËØB1

CHCH2CH2N(CH3)2

N

Cl

Chlorpheniramine

n.[Ò©]ÂÈÇüÃ×,ÂÈÇúÃ×ͨ ,Âȱ½ßÁ°· ,Æ˶ûÃô

CH2CH2NH2

2-phenylethylamine

n.[»¯]±½( »ù) ÒÒ°·

N

N

NHCH3

+

O-

Chlorodiazepoxide (librium)

librium [Ò©]ÀûÃßÄþ(=chlordiazepoxide)

N NH

CH2CH2NH2

Histamine

n.[Éú»¯]×é°·

19.5 Preparation of amines

19.5A Through nucleophilic substitution reactions

: NH3 + R X R NH3X-+ OH-

RNH2

: NH3 + NH3Br-+ OH-

CH3CH2 Br

CH3CH2 CH3CH2NH2 + Br-

CH3CH2NH2 CH3CH2 Br

+ (CH3CH2)2NHBr- OH-+

(CH3CH2)2NH + Br-

etc

CH3CHCO2H

Br

( 1 mol)

+ NH3

(70 mol)

CH3CH2CO2NH4

NH2

Alanine£¨±û°·Ëᣩ

Synthesis of primary amine

N

O

O

: KOHN- K+

O

O

H

acidic

Nucleophile reagent

R X

(- RX)

ÁÚ±½¶þ¼×õ£ÑÇ°·

Phthalimide

NH2-NH2N

O

O

R

HN

O

O

R

NHNH2

O

O

NH

NH

+ R NH2

Primary amine

ºÏ³É²®°·µÄ×îºÃ·½·¨

19.5B Preparation of amines through reduction of nitro

HNO3

H2SO4

NO2 NH2

1) H2 / Ni

[ H ]

Reduction methods;

2) Fe, HCl. NaOH

NO2NO2

NO2NH2

H2S

NH3, CH3CH2OH

m-Dinitrobenzene m-Nitroaniline

( 70 - 80 %)

用硫化氢（ hydrogen sulfide) 还原二硝基苯，只还原一个硝基。

19.5C Preparation of amines through reductive amination

O

R'

R

Aldehyde or Ketone

NH3

[ H ]R C

H

R'

NH2 (1o Amine)

R CH

R'

NH R''R''NH2

[ H ]

R''R'''NH[ H ]

R CH

R'

NR''R'''

(2o Amine)

(3o Amine)

Mechanism for reductive amination

O

R'

R

Aldehyde or Ketone

R''NH2+

(H)R

R'

OH

NHR'' R

R'

NR''- H2O

Imine

R

R'

NH R''

(2o Amine)

H2

Ni

先亲核加成，然后消除，再还原的胺。

Three specific examples of reductive aminations follow:

O

H

NH3, H2, Ni

90 atm, 40 - 70oCCH2NH2

Benzylamine(89%)

Benzaldehyde

O

H

CH3CH2NH2, H2, NiCH2NHCH2CH3

N-Benzylethanamine(89%)

Benzaldehyde

LiBH3CN

OLiBH3CN

(CH3)2NH

N

CH3

CH3

CyclohexanoneN,N-Dimethylcyclohexanamine

(52-54%)

19.5D Preparation of amines through reduction of amides, oxime

s, and nitrilesN

CH2CN

140 oC

Raney Ni

CH2CH2NH2

Cyclohexanone2-Phenylethanamine

(71%)

CH3

O

CH3

N-Methylacetanilide

+ LiAlH4 N

CH3

CH2CH3

N-Ethyl-N-methylaniline

diethyl ether

2) H2O

N OHNa, CH3CH2OH

NH2

CyclihexylamineOxime

(50-60%)

19.5E Preparation of amines through the Hofmann and curtius r

earrangements1) Hofmann rearrangement or Hofmann degradation （霍夫曼重排 或霍夫曼降级） --- 制备

伯胺

R

O

NH2 + Br2 + 4NaOH RNH2 + 2NaBr + Na2CO3 + 2 H2O

O

NH2 + Br2 + 4NaOH PhNH2 + 2NaBr + Na2CO3 + 2 H2O

2 ） The Curtius rearrangement ( 库尔提斯重排） -- 制备伯胺

R

O

Cl

Acyl chloride

NaN3

R

O

N3

Acyl azide

R

O

N- N N+

R N C O

Isocyanate

H2OR NH2 + CO2

Primary amine

ÒìëæËáõ¥

H3C

O

Cl

Acyl chloride

NaN3

H3C

O

N3

Acyl azide

H2O+ CO2CH3 NH2

Methyl amine

19.7A Reactions of primary aliphatic amines with nitrous acid

Primary aliphatic amines react with nitrous acid through a reaction called diazotization （重氮化作用） to yield highly unstable aliphatic diazo

nium salts( 重氮盐） .

R NH2 + NaNO2 + 2HCl R N N X-+

Aliphatic diazonium salt(highly unstable)

R+ + X-

HNO2

(alkenes, alcohols. alkyl halides)

Ph NH2 + NaNO2 + 2HCl Ph N N X-+

Arenediazonium salt(stable if kept below 5 oC)

HNO2

5 oC+ NaX + 2 H2O

19.7C Reactions of secondary amines with nitrous acid

(CH3)2NH + NaNO2 + 2HCl

HNO2

5 oC(CH3)2N N O

Dimethylamine N-Nitrosodimethylamine( a yellow oil)

N

CH3

H

+ HCl + NaNO2 N

CH3

N O

N-Nitroso-N-methylaniline(87-93%) (a yellow oil)

HNO2

N-Methylaniline

19.7D Reactions of tertiary amines with nitrous acid

N

CH3

CH3

+ HCl + NaNO2 N

CH3

CH3

p-Nitroso-N,N-dimethylaniline(80-89%)

HNO2N,N-Dimethylaniline

8 oCON

因氮上没有氢，故在二甲氨基的苯环的对面发生亚硝化。

19.8 Replacement reactions of arenediazonium salts ( 重氮盐的取

代） Diazonium salts are highly useful intermediates in the synthesis of aromatic compounds, because the diazonium group can be replaced by any one of a number of other atoms or groups, including –F, -Cl, -

Br, -CN, -OH, and –H.

19.8A Synthses using diazonium salts

N

H

H

HCl + NaNO2 N2+

HNO2

5 oC+

N N+ Cl-

N2+

N N+ Cl-

H2O+. heatOH

CuClCl

Br

CuBr

CN

CuCN

KI

I

1) HBF4

2) heat F

H

H3PO2

19.8B The sandmeyer reaction: Replacement of the diazonium g

roup by –Cl, -Br, or -CNCH3

NH2

o-Toluidine

HCl, NaNO2

H2O 0 - 5 oC

CH3

N2ClCuCl

15-60 oC

CH3

Cl

+ N2

NH2

HBr, NaNO2

H2O 0 - 5 oC

CH3

N2 Br-

CuBr

100 oC

CH3

Br

+ N2

Cl

+

m-Bromochlorobenzene

m-Chloroaniline

19.8C Replacement by -INO2

NH2

NaNO2, H2SO4

H2O

0-5 oC

NO2

N2+HSO4

-

KI

I

NO2

p-Nitroaniline p-Iodonitrobenzene

+ N2

19.8D Replacement by -FCH3

NH2

m-Toluidinem-Methyl aniline

1) NaNO2, H2SO4

2) HBF4

CH3

N2+BF4

-

heat

CH3

F

m-Fluorotoluene

(69%)

19.8E Replacement by -OH

H2O100 oC

NH2

NO2

m-Nitroaniline

1) NaNO2, H2SO4

N2+HSO4

-

NO2

OH

NO2

m-Nitrophenol

(74-79%)

H2O

0-5 oC

+ N2H2SO4

19.8F Replacement by -H （ Deamination by diazotization) 通过重氮化脱氨基）

NH2

NaNO2, HCl

H2O(0-5 oC)

N2+Cl -

H3PO2

H2O25 oC

H

+ N2

CH3 CH3

Br

NaNO2, HCl

H2O(0-5 oC)

N2+Cl -

H3PO2

H2O25 oC

CH3

NO2

CH3

HNO3

H2SO4

Fe, HCl

CH3

NH2

CH3

(CH3CO)2O

CH3

NHCOCH3

Br2

FeBr3

CH3

NHCOCH3

Br

H2O, OH-

CH3

NH2

BrBr

CH3

Br

Toluene

p-Toluidine amino group is protected

removing protecting group m-Bromotoluene

Arenediazonium salt

19.9 Coupling reactions of arenediazonium salts

( 重氮盐的偶联反应）Arenediazonium ions are weak electrophiles: they react with highly reactive aromatic compounds—with phenols and tertiary arylamines—to yield azo compounds. This electrophilic aromatic substitution is often called a diazo coupli

ng reaction( 偶氮化合物） .

N NX-+

+R

R = -NR2, or -OH

N N R

N NX-+

+OH

N N OH

BenzenediazoniumChloride

Phenol

p-(phenylazo)phenol(orange solid)

¶Ô-±½Öصª»ù±½·Ó

0 oC

N NX-+

+N(CH3)2

N N N(CH3)2

BenzenediazoniumChloride

N,N-Dimethyl-p-(phenylazo)aniline(yellow solid)

N,N-¶þ¼×»ù-¶Ô±½Öصª»ù±½°·

0 oC

N,N-Dimethylaniline

CH3COONa

N NX-+

+

N N

BenzenediazoniumChloride

4-Methyl-2-(phenylazo)phenol

4-¼×»ù-2-±½Öصª»ù±½·Ó

0 oC

NaOH

OH

CH3

OH

CH3

(p-cresol)

4-Methylphenol

NaO3S N N N(CH3)2

Ëá¼îµÎ¶¨Ö¸Ê¾¼Á--¼×»ù³È

NH2HO3SNaNO2, HCl

0 - 5 oCN NX-+

HO3S

NaO3S N N N(CH3)2

N(CH3)2

NaOH

NaO3SHN N N(CH3)2

H+OH-

+

red color

yellow color

Synthesis of methyl orange 甲基橙的合成

甲基橙的变色范围 3.1-4.4

19.10 Reactions of amines with sulfonyl chlorides

( 胺与磺酰氯的反应）Primary and secondary amines react with sulfonyl chlorides to form sulfonamides ( 磺酰胺）

RNH2 + Cl S Ar

O

O

(-HCl)RNH S Ar

O

O

1o Amine Sulfonyl chloride N-Substituted sulfonamide

R2NH + Cl S Ar

O

O

(-HCl)R2N S Ar

O

O

2o Amine Sulfonyl chloride N-Substituted sulfonamide

19.10A The Hinsberg test ( 兴斯堡测试）

Sulfonamide formation is the basis for a chemical test, called the Hinsberg test, that can be used to demonstrate whether an amine is

primary, secondary, or tertiary.

RNH2

RNH S Ar

O

O

1o Amine

R2NH + Cl S Ar

O

O

(-HCl)R2N S Ar

O

O

2o Amine

Sulfonyl chloride

KOH

R3N

3o Amine

R3N

KOH

It is removed by distillation

RN- S Ar

O

O

R2N S Ar

O

O

K+

Water-soluble salt(clear solution)

Water-insoluble salt

filter

RN- S Ar

O

O

K+

R2N S Ar

O

O

R2NH

RNH2

1) HCl

2) H2O

1) HCl

2) H2O

¹ýÂË

¹ÌÌå

ÒºÌå

19.11 The Sulfa Drugs: Sulfanilamide n.[ 化 , 医 ] 磺胺

H2N S NH2

O

O

Sulfanilamide

ɱÁ´Çò¾ú

H2N S NH

O

O

Sulfapyridine

N

n.[»¯,Ò½] »Ç°· bßÁà¤

H2N S NH

O

O

Sulfadiazine

N

N

n.[»¯,Ò½] »Ç°· à×à¤

H2N S NH

O

O

Sulfathiazole

S

N

n.[»¯] »Ç°· Èûßò

19.11D Synthesis of sulfa DrugesNH2

(CH3CO)2O

NHCOCH3

ClSO2OH

80 oC, - H2O

NHCOCH3

SO2Cl

Aniline Acetanilide

p-Acetamidobenzene sulfonyl chloride

H2NR

H2N S NH

O

O

R

»Ç°· ÀàÒ©Îï

NHCOCH3

SO2NHR

1) dil. HCl

2) NaOH

A sulfanilamide

19.12 Analysis of amines

19.12A Chemical analysis----Hinsberg test

19.12B Spectroscopic analysis---

IR; 3300-3555cm-1, N-H stretching vibration,

1020-1220cm-1, C-N, stretching vibration1H NMR; δ1-5

19.13 Eliminations involving ammonium compounds

19.13A The Hofmann elimination

2 RCH2CH2N(CH3)3X-+

+ Ag2O + H2O 2 RCH2CH2N(CH3)3OH- + 2AgX

A quaternary ammonium halid

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A quaternary ammonium hydroxide

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150oC

RCH=CH2 + N(CH3)2 + H2O

Eliminaltion

+

150oC+ N(CH3)2 + H2O

EliminaltionCH3CH2CHCH3 OH-

N(CH3)3+

CH3CH2CH=CH2 + CH3CH=CHCH3

95% 5%

CH3CH2CHCH3 OH-

N(CH3)3+

150oC+ N(CH3)2 + H2O

Eliminaltion

S(CH3)3+

CH3CH2CH=CH2 + CH3CH=CHCH3

74% 26%

CH3CH2CHCH3

-OC2H5

The Hofmann rule----yield mainly the least substituted alkene.霍夫曼规则 ----- 主要消除产物是取代基较少的烯烃。

Homeworks

19.21, 19.26, 19.30, 19.31