Synthesis and characterization of benzimidazole by using O-phenylenediamine with different aldehydes and carboxylic acids in the presence of ρ-tsOh as a catalyst

Article abstract of DOI:10.13005/ojc/3404054

This research paper deals with the synthesis and diagnose of Benzimidazole rings which were have been prepared by using two different methods in which used starting material o-phenylenediamine with different compounds. The first method is with aldehydes such as 4-Chlorobenzaldehyde, 4-N, N-Dimethylbenzaldehyde, and Formaldehyde. The second is with carboxylic acids such as salicylic acid, acetic acid, and butanoic acid. ρ-T_SOH has been using as a catalyst in the synthesis methods above and used F.T.I.R and HNMR spectroscopy are used for diagnosing the prepared rings in addition to the physical properties.

Full text of DOI:10.13005/ojc/3404054

ISSN: 0970-020 X
CODEN: OJCHEG
2018, Vol. 34, No.(4):
Pg. 2131-2136
ORIENTAL JOURNAL OF CHEMISTRY
An International Open Free Access, Peer Reviewed Research Journal
www.orientjchem.org
Synthesis and Characterization of Benzimidazole by Using
o-Phenylenediamine with Different Aldehydes and Carboxylic
Acids in the Presence of ρ-TSOH as a Catalyst
ABDULLAH JAWAD KADHIM1* and ALI CHAZI KAZIM2
1,2University of Al-Qadisiyah, College of Education, Chemistry department, Iraq.
*Correponding auhtor E-mail: abdullah.kadhim@qu.edu.iq
http://dx.doi.org/10.13005/ojc/3404054
(Received: March 23, 2018; Accepted: May 27, 2018)
ABSTRACT
This research paper deals with the synthesis and diagnose of Benzimidazole rings which were
have been prepared by using two different methods in which used starting material o-phenylenediamine
with different compounds. The first method is with aldehydes such as 4-Chlorobenzaldehyde,
4-N, N-Dimethylbenzaldehyde, and Formaldehyde. The second is with carboxylic acids such as
salicylic acid, acetic acid, and butanoic acid. ρ-TSOH has been using as a catalyst in the synthesis
methods above and used F.T.I.R and HNMR spectroscopy are used for diagnosing the prepared
rings in addition to the physical properties.
Keywords: Aldehydes, Benzimidazole, Carboxylic Acids, ρ-(Tolune sulphonic acid ).
INTRODUCTION
phenylenediamines and aldehydes3 and with
aryl-aldehydes by using an acidic agent and also
with silica gel at room temperature4. ρ-TsOH
has been used as a neutral acid catalyst to
synthesize a number of benzimidazoles5. It is
considered as an important, effective, available
and inexpensive incentive6. Also, there are many
ways to synthesize benzimidazole by using different
catalysts such as Nanocrystalline oxides with iodine7,
Benzimidazole is one of the heterocyclic
compounds that shows different biological qualities
such as antibacterial and antifungal1. Also, some
Benzimidazoles have an effect on human viruses
such as cytomegalovirus2 .There are two procedures
for the synthesis of 2-substituted Benzimidazoles.
The first is the reaction of phenylenediamines
and carboxylic acids or its derivatives by heating3
in strong drying conditions4. The second includes
a two-step procedure that includes the oxidative
cyclodehydrogenation of Schiff bases, which
are often generated from the condensation of
8
H2O2/HCl and Cu(OTf)2 , HCl9. In this work, the
aim was the synthesis of benzimidazole rings by
using one catalyst is ρ-TsOH as in previous studies
above, which have used one catalyst in different
circumstances.
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Instruments
important absorption packs of functional groups
for the synthesis Benzimidazole derivatives from
aldehydes and carboxylic acids with presence of
ρ-TSOH as a catalyst in the different conditions.
1-
Melting points have been determined by using
Melting pointSMP3 apparatus.
2-
F.T.I.R spectra have been recorded by using
FourierTransform Infrared Spectrophotometre
(F.T.I.R) 8400 S Shimadzu apparatus.
HNMR spectra have been recorded by using
NMR Spectrometer 400 MHz, Avance III 400
Bruker, Germany.
U.V. spectra have been recorded by using
U.V-Visible Spectrophotometer 1650 PC
Shimadzu apparatus.
2-(4-Chlorophenyl) -1H-Benzimidazole (A)
The F.T.I.R spectrum of this compound
3-
4-
shows appearance of an absorption pack at
3379 cm-1 refers to (N-H) group and appearance of
an absorption pack at 686 cm-1 refers to (C-Cl) bond.
HNMR (400 MHz) δ(ppm) Benzi. (7.26t 2H) and
(7.71t 2H), Ar (7.31 and 7.61), N-H(3.42s).Table (2)
shows the other absorption packs of the compound
in the F.T.I.R spectrum.
ExPERIMENTAL
TheGeneralMethodforSynthesizingBenzimidazoles
from Aldehydes
2-(4-N,N- Dimethylaniline)-1H-Benzimidazole (B)
The F.T.I.R spectrum of this compound
A solution of Aldehyde (0.01 mole),
o-phenylenediamine(0.01 mol) and DMF (3 ml) has
been mixed with ρ-TsOH (20 ml). The mixture has
been heated and stirred at 80Co for 2-3 h then cooled
to reach room temperature, the mixture has been
added dropwise with stirring into mixture of Na2CO3
(0, 01mole) and H2O (20 ml), the product has been
filtered, washed by H2O, then dried2 to yield A, B and
C compounds.
shows an absorption pack at 3301 cm-1 refers to
(N-H) group and appearance of an absorption
pack at 2916 cm-1 refers to (C-H) aliphatic. H-NMR
(400 MHz) δ(ppm) Ar (6.91 and 7.31), Benzi.
(7, 26t 2H 7.69t 2H), N-H(4.42d), CH3(2.91).Table (2)
shows the other absorption packs of the compound
in the F.T.I.R spectrum.
1H-Benzimidazole (C)
The F.T.I.R spectrum of this compound
shows an absorption pack at 3409 cm-1 refers to
(N-H) group and an absorption pack at 2923 cm-1
refers to (C-H) aliphatic. HNMR (400 MHz ) δ(ppm)
Benzi. (7.68t 2H) and (7.26-7.30t 2H), N-H(2.9Hz),
Benz.-CH(7.90Hz). Table (2) shows the other
absorption packs of the compound in the F.T.I.R
spectrum.
TheGeneralMethodforSynthesizingBenzimidazole
from Carboxylic Acids
A solution of Carboxylic acid (0.01 mole),
o-phenylenediamine(0.01 mole) and toluene (10 ml)
has been mixed with ρ-TsOH (20 ml). The mixture
has been refluxed for 2-3 h then cooled, filtered and
dried10 to yield D, E and F compounds.
RESULT AND DISCUSSION
2-(2-hydroxy phenyl)-1H-Benzimidazole (D)
F.T.I.R spectrum of this compound shows
an absorption pack at 3425 cm-1 refers to (O-H) group
Synthesis compounds characterized by
F.T.I.R. and H-NMR spectroscopy have showed an
Table 1: Physical Properties of Compounds
Molecular formula
Solvent Yield % m. p. Co
C13H9N2Cl
Compounds
Color
A
B
C
D
E
F
DMF
DMF
78
72
85
81
72
68
294-298
237-240
115-118
151-157
Oil
Brown
Nutty
Yellow
Yellow
Nutty
Nutty
C15H15N3
C6H6N2
DMF
C13H10N2O
C8H8N2
C10H12N2
Toluene
Toluene
Toluene
249 dec.

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KADHIM et al., Orient. J. Chem., Vol. 34(4), 2131-2136 (2018)
and appearance of an absorption pack at 1157 cm-1
refers to (C-O) bond in addition to an absorption pack
(N-H) group at 3240 cm-1.HNMR (400 MHz ) δ(ppm)
Benz. (7.26t 2H) and (7.75t 2H), Ar (7.35-7.00),
N-H(2,93s), O-H(7.97). Table (2) shows the other
absorption packs of compound in F.T.I.R spectrum.
Scheme 1
2-Methyl-1H-Benzimidazole (E)
The F.T.I.R spectrum of this compound
2-Propyl-1H-Benzimidazole (F)
The F.T.I.R spectrum of this compound
shows an absorption pack at 3209 cm-1 refers to
(N-H) group and an absorption pack at 2962 and
2931 cm-1 to (C-H) aliphatic. HNMR (400 MHz)
δ(ppm) Benz.(7.29t 2H) and (7.71t 2H), N-H(4.28s),
-CH2-CH2(2.42S), CH2-CH2-(1,43S), CH3(0.92S).
Table (2) shows the other absorption packs of the
compound in the F.T.I.R spectrum.
shows an absorption pack at 3178 cm-1 refers to
(N-H) group and an absorption pack at 2916 cm-1
refers to (C-H) aliphatic. HNMR (400 MHz ) δ(ppm)
Benz. (7.26t 2H and 7.71t 2H), N-H(2.45), CH3
(2.20s).Table (2) shows the other absorption packs
of the compound in the F.T.I.R spectrum.
Fig. 1. (F.T.I.R) Spectrum of Compound(A)

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Fig. 2. (H-NMR) Spectrum of Compound(B)
Fig. 3. (F.T.I.R) Spectrum of Compound(C)
Fig. 4. (F.T.I.R) Spectrum of Compound(D)

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Fig. 5. (F.T.I.R) Spectrum of Compound(E)
Fig. 6. (F.T.I.R) Spectrum of Compound (F)
Table 2: Absorption Peeks of Compounds in F.T.I.R. Spectroscopy
Compounds
Name of compound
UV (nm) (C-H) aromatic (C=N)(C=C)
cm-1
(C-N)
1311
A
B
2-(4-Chlorophenyl) -
1H-Benzimidazole
2-(4-N,N- Dimethylaniline)
-1H-Benzimidazole
318
379
3062
1512-1604
293
374
316
3039
3062
3024
1496-1604
1512-1604
1666-1612
1365
1303
1249
C
D
1H-Benzimidazle
2-(2-Hydroxy Phenyl)-
1H-Benzimidazole
293
396
E
F
2-Methyl-1H-Benzimidazole 357
2-Propyl-1H-Benzimidazole 357
3062
3070
1519-1681
1512-1620
1311
1157

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CONCLUSION
techniques FT.I.R and H-NMR have been used to
diagnose the prepared rings.
In this study, a number of rings of
benzimidazole have been synthesized from the
reaction of o-phenylenediamine with different
aldehydes and different carboxylic acids by using
ρ-TSOH as a catalyst in all synthesis processes.The
synthesis results have given a high percentage of
the products with different solvent used.The spectral
ACKNOWLEDGMENT
The authors gratefully acknowledges
Chemistry department, University of Al-Qadisiyah,
Iraq for providing lab facilities to carry out this work.
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