•Reaction of nitrilimines with 2-substituted aza-heterocycles

•Adel M. Awadallah

• Chemistry Department, Faculty of Science,•Islamic University of Gaza, P. O. Box108, Gaza, Palestine;

• Tel. +970-8-2823311, Fax: +970-8-2823310 ,•e-mail awada@iugaza.edu.ps

• Nirilimines As 1,3-Dipoles• 1,3-Dipoles• A 1,3-Dipole is a three-atom π-electron system with 4π-

electrons delocalized over the three atoms.

•

ab

ca b + __ +

c

• Nitrilimines:• Nitrilimines are flexible system of three atoms over which

four π- electrons are delocalized, they are typical 1,3-dipolar species having the resonance structures shown below:

• Resonance structures of Nitrilimines

NNAr

MeO

ONNAr

Me

O

R C N N Ar

_

R C N N Ar

R C N N Ar R C N N Ar

..

..

..

.......... R C N N Ar

..

......

.._

__ ++

++

CCCC

Blue: Electrophilic Red: Nucleophilic

• Reactions of 1,3-Nitrilimines:

NNAr

Me

O

O

EtO

R

NH2 NH2

N

NNO

Me

Ar

R

NH

R

NH

NO

Me

Ar

NH

NNO

MeO

Ar

NHN

N NH

MeAr

R

CC

C N

C

H2N

H2N

Cycloaddition

Nucleophilic addition

Cyclocondensation

•Reaction of Dinucleophiles with NitriliminesReaction with 2-aminopyridine and 2-aminopyrazine

Cl

NH

NCH3

O

Ar

X

NNH2X

NN

CH3 N NAr

+Et3N

X= CH, N

• Reaction with 2,3-diaminobenzene and 2,3-diaminopyridine;

Cl

NH

NY

O

Ar

NNH2

NH2

NN

Y N NAr

NH2

NH2

NH2

NHN

N NH

Ar

CH3 NNH2

NH2

NN

O N NH

Ar

NH2

Et3N, Y = OCH3

Et3N, Y = CH3 Et3N, Y = CH3

•Our Work

Cl

NH

N

O

ArY

N

NH

NH2

NH

NN

N NH

O

Ar

NH

NN

N NCH3

Ar

N

NNH2

N NH

CH3

Ar

O

N

NNH2

N NH

Ar

O

MeO

+

Et3NEt3N

Y = OCH3Y = CH3

Expected Expected

Found Found

• Reaction with 2-Cyanomethylbenzimidazole• Quite recently, Awadalah reported that nitrilimines react with 2-

cyanomethyl benzimidazole to afford pyrrolo(1,2-a)benzimidazoles.

Cl

NH

NCH3

O

Ar

N

NH

CH2

NC

NH

N

N NCH3

Ar

N

NN

Ar

NH

NN

CH3

+Et3N1

2

3

4

The structure of compound 4 was confirmed by X-ray crystal structure.

• Our Work•Reaction of Nitrilimines (containing ester moiety)

with cyanomethyl-benzimidazole.

Cl

NH

N

O

ArMeO

N

NH

CH2

NC

NH

N

N NH

O

Ar

N

N

N

N NH

Ar

O

CH2

MeO

NC

+Et3N

Expected

Found

Et3N

• Reaction of Nitrilimines with Ethyl Pyridine-2-acetate.

Cl

NH

NY

O

Ar

N NCH3

Ar

N

EtO2C

NCH2

EtO2C

N NH

Ar

N

EtO2C

O

N NH

Ar

N

EtO2C

O

MeO H NH

N

O

Ar

NEtO2C

MeO

H

Chemical shift

+Et3N

Y = CH3

Et3N

Y = OCH3

Expected

and Found

Expected

Expected

Found

1H NMr 4.1 ppm13C NMR 76.6 ppm

•Reaction of Nitrilimines with 2-benzothiazole acetonitrile.

Cl

NH

NY

O

Ar

N

SCH2

NCS

N

N NCH3

Ar

N

S

N

N NH

O

Ar

NY= CH3

Y = OMe

Cl

NH

NY

O

Ar

N

SNH2

S

NN

N NCH3

Ar

+ Et3NEt3N

ExpectedExpected

+

Expected

??????? Found ???????

وتقدير • شكراألردنية. - • الجامعة زهرة أحم�د جالل د

اإلسالمية / – • الجامعة العشي دينا األستاذةاإلسالمية / – • الجامعة العصار منى الطالبة

استماعكم • لحسن لكم شكراالله • ورحمة عليكم والسالم

وبركاته