Efficient and green synthesis of 1,2-disubstituted benzimidazoles and quinoxalines using bronsted acid ionic liquid, [(CH2) 4SO3HMIM][HSO4], in water at room temperature

Article abstract of DOI:10.1080/00397910903062280

1,2-Disubstituted benzimidazoles and quinoxalines have been synthesized in the presence of Brnsted acid ionic liquid, [(CH₂)₄SO ₃HMIM][HSO₄], in water at ambient temperature.

Full text of DOI:10.1080/00397910903062280

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Efficient and Green Synthesis of 1,2-
Disubstituted Benzimidazoles and
Quinoxalines Using Br⊘nsted Acid Ionic
Liquid, [(CH2)4SO3HMIM][HSO4], in Water
at Room Temperature
Yahya S. Beheshtiha a , Majid M. Heravi a , Mina Saeedi a , Narges
Karimi a , Masumeh Zakeri a & Niloofar Tavakoli-Hossieni b
a Department of Chemistry, School of Sciences, Azzahra University,
Vanak, Tehran, Iran
b Department of Chemistry, Faculty of Sciences, Islamic Azad
University, Mashhad Branch, Mashhad, Iran
Published online: 12 Mar 2010.
To cite this article: Yahya S. Beheshtiha , Majid M. Heravi , Mina Saeedi , Narges Karimi , Masumeh
Zakeri & Niloofar Tavakoli-Hossieni (2010) Efficient and Green Synthesis of 1,2-Disubstituted
Benzimidazoles and Quinoxalines Using Br⊘nsted Acid Ionic Liquid, [(CH2)4SO3HMIM][HSO4], in Water
at Room Temperature, Synthetic Communications: An International Journal for Rapid Communication
of Synthetic Organic Chemistry, 40:8, 1216-1223, DOI: 10.1080/00397910903062280
To link to this article: http://dx.doi.org/10.1080/00397910903062280
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Synthetic Communications1, 40: 1216–1223, 2010
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910903062280
EFFICIENT AND GREEN SYNTHESIS OF
1,2-DISUBSTITUTED BENZIMIDAZOLES AND
QUINOXALINES USING BRØNSTED ACID IONIC
LIQUID, [(CH2)4SO3HMIM][HSO4], IN WATER AT
ROOM TEMPERATURE
Yahya S. Beheshtiha,1 Majid M. Heravi,1 Mina Saeedi,1
Narges Karimi,1 Masumeh Zakeri,1 and
Niloofar Tavakoli-Hossieni2
1Department of Chemistry, School of Sciences, Azzahra University, Vanak,
Tehran, Iran
2Department of Chemistry, Faculty of Sciences, Islamic Azad University,
Mashhad Branch, Mashhad, Iran
1,2-Disubstituted benzimidazoles and quinoxalines have been synthesized in the presence of
Brønsted acid ionic liquid, [(CH2)4SO3HMIM][HSO4], in water at ambient temperature.
Keywords: Brønsted acid ionic liquid; 1,2-disubstituted benzimidazoles; quinoxalines; 1-(4-sulfonic
acid)butyl-3-methylimidazolium hydrogen sulfate
INTRODUCTION
Benzimidazole and quinoxaline derivatives exhibit significant and valuable
biological activities. Benzimidazoles show strong effects against different viruses
such as human immunodeficiency virus (HIV), herpes (HSV-1), RNA, influenza
and human cytomegalovirus (HCMV).[1] Also, anti-methicillin-resistant S. aureus
(MRSA) and anti-vancomycin-resistant enterococci (VRE) activities of some
benzimidazole derivatives have been proved.[2] Recently, a novel symmetrical bis-
benzimidazole has been designed as a DNA minor groove binder.[3]
Benzimidazoles have also been introduced as azo dyestuffs.[4] Quinoxalines’
biological activities are also conspicuous. Synthetic quinoxalines have been
employed in antibiotic structures such as echinomycin, leromycin, and actinomy-
cin.[5] Different substituted quinoxalines have been designed, synthesized, and
evaluated for their in vitro antitumor activity toward cell lines of nine different types
of human cancers.[6] In addition, some of its derivatives exhibit anticonvulsant
activity.[7] Moreover, their application in other industries such as dyes cannot be
Received April 12, 2009.
Address correspondence to Majid M. Heravi, Department of Chemistry, School of Sciences,
Azzahra University, Vanak, Tehran 1234, Iran. E-mail: mmh1331@yahoo.com
1216

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1,2-DISUBSTITUTED BENZIMIDAZOLES AND QUINOXALINES
1217
Scheme 1. 1-(4-Sulfonic acid)butyl-3-methylimidazolium hydrogen sulfate [(CH2)4SO3HMIM][HSO4]
as an efficient and recyclable catalyst for synthesis of 1,2-disubstituted benzimidazole and quinoxaline
derivatives.
ignored.[8] Consequently, the necessity of designing novel and particularly green
methods for synthesis of these precious heterocyclic compounds is recognized.
Synthesis of 1,2-disubstituted benzimidazoles is based mainly on condensation
of 1,2-diaminoarene derivatives with carboxylic acid derivatives,[9] aldehydes,[10] aryl
halides,[11] and orthoesters.[12] Alternatively, the palladium- and copper-catalyzed
intramolecular N-arylation starting from o-haloanilines has been used.[13] The most
common method for the synthesis of quinoxalines is the reaction of 1,2-diaminoar-
ene derivatives with 1,2-dicarbonyl compounds in different conditions. Recently,
various protocols have been introduced that achieve this goal efficiently.[14]
Organic synthesis in water attracts great attention because of cost, safety, and
environmental concerns. It is the best substitute for volatile and toxic organic
solvents, especially chlorinated hydrocarbons, which are broadly used in organic
synthetic procedures. Additionally, water exhibits special properties as compared
to commonly employed organic solvents. For example, several reactions accelerate
in water.[15] Aside from these advantages, when a water-soluble catalyst, such as
Brønsted acid ionic liquid (BAIL), is used, the insoluble products can be separated
by simple filtration, and the catalyst system can be recycled.
In this work, besides an ecofriendly moiety in the reaction, nontoxic BAIL,
1-(4-sulfonic acid)butyl-3-methylimidazolium hydrogen sulfate [(CH2)4SO3-
HMIM][HSO4] (Scheme 1), has been used, which possesses both green and efficient
catalytic effects in organic reactions.[16]
Generally, ionic liquids (ILs) are defined as fused salts with a melting point less
than 100 ꢀC, whereas salts with higher melting points are referred to as molten
salts.[17] Special properties of ILs, such as polarity, high thermal stability, immisci-
bility with a number of organic solvents, negligible vapor pressure, and recyclability,
are remarkable. Among different ILs, BAILs, which are related to protic ILs, possess
Brønsted acidity and have catalyst roles for many organic syntheses. In this class,
imidazolium salts have their own specific effects to their counterion.
Herein, [(CH2)4SO3HMIM][HSO4] has been introduced as a desirable IL that
catalyzes reaction of o-phenylenediamine with different aromatic aldehydes and also
the reaction of 1,2-diaminoarene derivatives with 1,2-diketones to synthesis 1,2-
disubstituted benzimidazoles and quinoxalines in water, respectively.
RESULTS AND DISCUSSION
In continuation of our efforts to synthesize 1,2-disubstituted benzimidazoles[10b]
and qunoxalines,[14a–d] and also achieve organic reactions in water,[14b,18] we have
developed an environmentally friendly, simple, and efficient method for the synthesis
of various 1,2-disubstituted benzimidazole and quinoxaline derivatives (Schemes 2