Azo Coupling

8/20/2019 Azo Coupling

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Nitrosation of AlkylaminesNitrosation of Alkylamines


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Nitrite Ion, Nitrous Acid, and Nitrosyl CationNitrite Ion, Nitrous Acid, and Nitrosyl Cation

HH++

– –OO••••••

••••••NN OO

••••••••

••••OO•••• ••••

NN OO••••

••••

••••HH

HH++

OO••••NN OO

•••• ••••

HH

HH

++••••

++

••••NN OO

•••• ••••++OO •

•••

HH

HH

••••


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Nitrosyl Cation and NitrosationNitrosyl Cation and Nitrosation

++

••••NN OO

•••• ••••++

••••NN

NN••••NN OO

•••• ••••

++


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Nitrosation of Secondary AlkylaminesNitrosation of Secondary Alkylamines

++

••••NN OO

•••• ••••

••••NN

HH

++

NN••••NN OO

•••• ••••

++

HH

++HH

++

NN••••NN OO

•••• ••••

••••

nitrosation ofnitrosation ofsecondary aminessecondary amines

gives angives an N N -nitroso-nitroso

amineamine


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ExampleExample

(CH(CH33))22NNHH•••• NaNONaNO22, HCl, HCl

HH22OO(88-!")(88-!")

••••(CH(CH33))22NN

••••NN OO

•••• ••••


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Some N-Nitroso AminesSome N-Nitroso Amines

N N -nitroso#yrrolidine-nitroso#yrrolidine

(nitrite-c$red %acon)(nitrite-c$red %acon)

NN

NNOO

N N -nitrosonornicotine-nitrosonornicotine

(to%acco smo&e)(to%acco smo&e)

NN

NNOO

NN

(CH(CH33))22NN NN OON N -nitrosodimet'ylamine-nitrosodimet'ylamine

(leat'er tanning)(leat'er tanning)


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Nitrosation of Primary AlkylaminesNitrosation of Primary Alkylamines

++ analogo$s toanalogo$s tonitrosation ofnitrosation of

secondary aminessecondary amines

to t'is #ointto t'is #oint

++••••NN OO

•••• ••••

••••NN

HH

HH

NN••••NN OO

•••• ••••

++

HH

HH

++HH

++

NN••••NN OO

•••• ••••

••••

HH


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NN••••NN OO

•••• ••••

••••

HH

HH++

NN••••NN OO

••••••••

HH HH

++

t'is s#ecies reacts f$rt'er t'is s#ecies reacts f$rt'er

••••NN

••••NN OO

••••••••

HH

HH

++

++

HH

HH ++••••NN

••••NN OO••••

HH


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++

HH

••••NN

••••NN OO••••

HH

++NN NN ••••

HH

••••OO

HH

••••++

nitrosation of anitrosation of a

#rimary al&ylamine#rimary al&ylamine

gives an al&ylgives an al&yl

diaoni$m iondiaoni$m ion

#rocess is called#rocess is called

diazotizationdiazotization


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Alkyl Diazonium Ions Alkyl Diazonium Ions

++NN NN ••••

al&yl diaoni$m ionsal&yl diaoni$m ionsreadily lose Nreadily lose N22 toto

give car%ocationsgive car%ocations

++ ++ NN NN ••••

••••


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Example: Nitrosation of ,-Dimet!ylpropylamineExample: Nitrosation of ,-Dimet!ylpropylamine

NNHH22

NN NN++HONOHONO

HH22OO

OOHH

(8!")(8!")

++

(2")(2")(3")(3")

++ – – NN22


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*'ere is no $sef$l c'emistry associated it' t'e*'ere is no $sef$l c'emistry associated it' t'e

nitrosation of tertiary al&ylaminesnitrosation of tertiary al&ylamines

Nitrosation of "ertiary AlkylaminesNitrosation of "ertiary Alkylamines

••••NN

NN••••NN OO

•••• ••••

++


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Nitrosation of ArylaminesNitrosation of Arylamines


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reaction t'at occ$rs isreaction t'at occ$rs iselectro#'ilic aromatic s$%stit$tionelectro#'ilic aromatic s$%stit$tion

Nitrosation of "ertiary ArylaminesNitrosation of "ertiary Arylamines

NN(CH(CH22CHCH33))22

(")(")

. NaNO. NaNO22, HCl,, HCl,

H H22O, 8/CO, 8/C

2 HO2 HO – –

NN(CH(CH22CHCH33))22

NNOO


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similar to secondary al&ylamines0similar to secondary al&ylamines0

givesgives N N -nitroso amines-nitroso amines

Nitrosation of N-AlkylarylaminesNitrosation of N-Alkylarylamines

NaNONaNO22, HCl,, HCl,

HH22O, .!/CO, .!/C

NNHCHHCH33

(81-3")(81-3")

NNCHCH33

NN OO


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Nitrosation of Primary ArylaminesNitrosation of Primary Arylamines

gives aryl diaoni$m ionsgives aryl diaoni$m ions

aryl diaoni$m ions are m$c' more sta%le t'anaryl diaoni$m ions are m$c' more sta%le t'an

al&yl diaoni$m ionsal&yl diaoni$m ions

most aryl diaoni$m ions are sta%le $nder t'emost aryl diaoni$m ions are sta%le $nder t'e

conditions of t'eir formation (!-.!/C)conditions of t'eir formation (!-.!/C)

r r

NN NN++

NN NN++ fastfast

sloslo

++ ++ NN22

r r

++ ++NN

22


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Example:Example:

(CH(CH33))22CHCH NNHH22

NaNONaNO22, H, H22OO44

HH22O, !-/CO, !-/C

(CH(CH33))22CHCH NN NN++

HOHO44 – –


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Synt!etic #ri$in of Aryl Diazonium SaltsSynt!etic #ri$in of Aryl Diazonium Salts

r r HH

r r NNOO22

r r NNHH22

r r NN NN++


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Synthetic TransformationsSynthetic TransformationsofAryl Diazonium SaltsofAryl Diazonium Salts


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"ransformations of Aryl Diazonium Salts"ransformations of Aryl Diazonium Salts

r r NN NN++

r r HH

r r OOHH

r r 55

r r 66

r r 7r 7r r r ClCl

r r CNCN


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Preparation of P!enolsPreparation of P!enols

r r NN NN++

r r OOHH

HH22OO, 'eat, 'eat


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ExampleExample

2 H2 H22O, 'eatO, 'eat

(CH(CH33))22CHCH NNHH22

. NaNO. NaNO22, H, H22OO44

HH22O, !-/CO, !-/C

(CH(CH33))22CHCH OOHH

(13")(13")


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r r NN NN++

r r HH

r r OOHH

r r 55

r r 66

r r 7r 7r r r ClCl

r r CNCN


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Preparation of Aryl IodidesPreparation of Aryl Iodides

r r NN NN++

r r 55

reaction of an aryl diaoni$m salt it'reaction of an aryl diaoni$m salt it'

#otassi$m iodide#otassi$m iodide

55


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ExampleExample

2 2 55, room tem#, room tem#

. NaNO. NaNO22, HCl, HCl

HH22O, !-/CO, !-/C

(12-83")(12-83")

NNHH22

7r 7r

II

7r 7r


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r r NN NN++

r r HH

r r OOHH

r r 55

r r 66

r r 7r 7r r r ClCl

r r CNCN


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Preparation of Aryl %luoridesPreparation of Aryl %luorides

r r NN NN++

r r 66

'eat t'e tetrafl$oro%orate salt of a diaoni$m ion0'eat t'e tetrafl$oro%orate salt of a diaoni$m ion0#rocess is called t'e c'iemann reaction#rocess is called t'e c'iemann reaction


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ExampleExample

(98")(98")

NNHH22

CCHCCH22CHCH33

OO

2 H762 H7644


HH22O, !-/CO, !-/C

3 'eat3 'eat

66

CCHCCH22CHCH33

OO


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r r NN NN++

r r HH

r r OOHH

r r 55

r r 66

r r 7r 7r r r ClCl

r r CNCN


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Preparation of Aryl C!lorides and &romidesPreparation of Aryl C!lorides and &romides

r r NN NN++

r r 7r 7r r r ClCl

aryl c'lorides and aryl %romides are #re#ared %yaryl c'lorides and aryl %romides are #re#ared %y

'eating a diaoni$m salt it' co##er(5) c'loride or'eating a diaoni$m salt it' co##er(5) c'loride or

%romide%romide

s$%stit$tions of diaoni$m salts t'at $se co##er(5)s$%stit$tions of diaoni$m salts t'at $se co##er(5)

'alides are called'alides are called Sandmeyer Sandmeyer reactionsreactions


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ExampleExample

(98-1.")(98-1.")

NNHH22

NONO222 C$2 C$ClCl, 'eat, 'eat


HH22O, !-/CO, !-/C

ClCl

NONO22


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ExampleExample

(8-")(8-")

2 C$2 C$7r 7r , 'eat, 'eat

. NaNO. NaNO22, H7r,, H7r,

HH22O, !-.!/CO, !-.!/C

NNHH22

ClCl

7r 7r

ClCl


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r r NN NN++

r r HH

r r OOHH

r r 55

r r 66

r r 7r 7r r r ClCl

r r CNCN


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Preparation of Aryl NitrilesPreparation of Aryl Nitriles

r r NN NN++

r r CNCN

aryl nitriles are #re#ared %y 'eating a diaoni$maryl nitriles are #re#ared %y 'eating a diaoni$m

salt it' co##er(5) cyanidesalt it' co##er(5) cyanide

t'is is anot'er ty#e of andmeyer reactiont'is is anot'er ty#e of andmeyer reaction


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ExampleExample

(94-1!")(94-1!")

2 C$CN, 'eat2 C$CN, 'eat


HH22O, !/CO, !/C

NNHH22

CHCH33

CNCN

CHCH33


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r r NN NN++

r r HH

r r OOHH

r r 55

r r 66

r r 7r 7r r r ClCl

r r CNCN


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r r NN NN++

r r HH

'y#o#'os#'oro$s acid (H'y#o#'os#'oro$s acid (H33:O:O22) red$ces diaoni$m) red$ces diaoni$m

salts0 et'anol does t'e same t'ingsalts0 et'anol does t'e same t'ing

t'is is calledt'is is called reducti'e deaminationreducti'e deamination


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ExampleExample

(1!-1")(1!-1")

NaNONaNO22, H, H22OO44,,

HH33:O:O22

NNHH22

CHCH33 CHCH33


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(alue of Diazonium Salts(alue of Diazonium Salts

.).) allos introd$ction of s$%stit$ents s$c' asallos introd$ction of s$%stit$ents s$c' as

OH, 6, 5, and CN on t'e ringOH, 6, 5, and CN on t'e ring

2)2) allos #re#aration of ot'erise diffic$ltlyallos #re#aration of ot'erise diffic$ltly

accessi%le s$%stit$tion #atternsaccessi%le s$%stit$tion #atterns


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ExampleExample

7r 7r

7r 7r 7r 7r

NNHH22

7r 7r

7r 7r

7r 7r

(14-11")(14-11")

NaNONaNO22, H, H22OO44,,

HH22O, CHO, CH33CHCH22OHOH

NNHH22

7r 7r 22

HH22OO

(.!!")(.!!")


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Azo CouplingAzo Coupling


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Azo Couplin$ Azo Couplin$

;iaoni$m salts are ea& electro#'iles;iaoni$m salts are ea& electro#'iles

eact it' strongly activated aromaticeact it' strongly activated aromatic

com#o$nds %y electro#'ilic aromaticcom#o$nds %y electro#'ilic aromatic

s$%stit$tions$%stit$tion

r r NN NN++

r


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ExampleExample

OHOH

++ CC99HHNN NN++

OHOH

NN NCNC99HH

ClCl – –

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Azo Coupling