Abstract
An efficient and green protocol has been introduced for the synthesis of benzimidazole derivatives using a pyruvic acid catalyst in the presence of water. Pyruvic acid catalyses the reaction of aromatic aldehydes with o-phenylenediamine efficiently, and products were obtained in good to excellent yields under sonication (50 °C) or under conventional heating (50 °C). The advantages of this synthetic methodology are the use of eco-friendly, commercially cheap, biodegradable catalyst, metal-free and Lewis acid-free mild reaction conditions with excellent yields, short reaction times, and compatible with a wide range of electronically diverse substrates. Pyruvic acid in water as a catalyst under ultrasound irradiation can be a better alternative to synthesize benzimidazole derivatives than some of the traditional methods.
Keywords: Pyruvic acid, benzimidazole, aldehyde, o-phenylenediamine, ultrasound irradiation, green chemistry, heterocyclic chemistry.
Graphical Abstract
[http://dx.doi.org/10.1002/jhet.5570390429]
[http://dx.doi.org/10.2165/00003495-199856060-00007] [PMID: 9878991]
[http://dx.doi.org/10.4236/gsc.2014.41006]
[http://dx.doi.org/10.1007/s11696-018-0540-5]
[http://dx.doi.org/10.1136/bmj.292.6521.660] [PMID: 2868774]
[http://dx.doi.org/10.1046/j.1365-4362.2001.01103.x] [PMID: 11277961]
[http://dx.doi.org/10.4269/ajtmh.2002.66.251] [PMID: 12139216]
[http://dx.doi.org/10.1039/C3RA47761D]
[http://dx.doi.org/10.1038/ncomms12654] [PMID: 27585494]
[http://dx.doi.org/10.1039/C9CC01585J] [PMID: 30931445]
[http://dx.doi.org/10.1002/bkcs.12261]
[http://dx.doi.org/10.1134/S1070428006030201]
[http://dx.doi.org/10.1081/SCC-200039340]
[http://dx.doi.org/10.1002/chem.201502487] [PMID: 26206475]
[http://dx.doi.org/10.1055/s-2000-7111]
[http://dx.doi.org/10.1016/j.molcata.2005.09.025]
[http://dx.doi.org/10.1016/j.catcom.2006.10.022]
[http://dx.doi.org/10.1002/adsc.200800317]
[http://dx.doi.org/10.1080/00397910802654815]
[http://dx.doi.org/10.3987/COM-04-10215]
[http://dx.doi.org/10.1016/j.tetlet.2011.08.047]
[http://dx.doi.org/10.1016/j.tet.2009.11.048]
[http://dx.doi.org/10.1016/j.tetlet.2010.07.132]
[http://dx.doi.org/10.3762/bjoc.12.235] [PMID: 28144309]
[http://dx.doi.org/10.1080/00397911.2010.522294]
[http://dx.doi.org/10.1021/jo901458k] [PMID: 19799443]
[http://dx.doi.org/10.1016/j.tetlet.2005.10.134]
[http://dx.doi.org/10.1021/jm0100638] [PMID: 11495587]
[http://dx.doi.org/10.1016/j.tetlet.2005.04.101]
[http://dx.doi.org/10.1111/j.1747-0285.2012.01394.x] [PMID: 22515497]
[http://dx.doi.org/10.1039/b823543k]
[http://dx.doi.org/10.1016/j.catcom.2007.03.011]
[http://dx.doi.org/10.1016/j.tetlet.2006.11.018]
[http://dx.doi.org/10.1002/jhet.5570450506]
[http://dx.doi.org/10.3987/COM-06-10785]
[http://dx.doi.org/10.1007/s10562-017-2232-0]
[http://dx.doi.org/10.1055/s-0030-1260764]
[http://dx.doi.org/10.1039/C5RA08183A]
[http://dx.doi.org/10.1002/anie.201004365]
[http://dx.doi.org/10.1021/acscombsci.6b00107] [PMID: 27631587]
[http://dx.doi.org/10.1021/jo401445j] [PMID: 24134516]
[http://dx.doi.org/10.1515/chempap-2016-0056]
[http://dx.doi.org/10.1007/s12039-010-0095-7]
[http://dx.doi.org/10.18052/www.scipress.com/ILCPA.25.61]
[http://dx.doi.org/10.1055/s-0034-1378783]
[http://dx.doi.org/10.1039/b212394k]
[http://dx.doi.org/10.1002/anie.200700990]
[http://dx.doi.org/10.1021/acs.chemrev.6b00457] [PMID: 28535680]
[http://dx.doi.org/10.1016/j.ultsonch.2014.06.015] [PMID: 25023825]
[http://dx.doi.org/10.1016/j.ultsonch.2010.11.016] [PMID: 21172736]
[http://dx.doi.org/10.1016/j.ultsonch.2015.01.002] [PMID: 25605585]
[http://dx.doi.org/10.1039/C6RA20895A]
[http://dx.doi.org/10.1055/s-0040-1707145]
[http://dx.doi.org/10.1002/anie.201915438]
[http://dx.doi.org/10.1007/s002530100804] [PMID: 11762589]
[http://dx.doi.org/10.1093/ajcn/56.4.630] [PMID: 1414961]
[http://dx.doi.org/10.1093/ajcn/59.2.423] [PMID: 8310996]
[http://dx.doi.org/10.1152/jappl.1990.69.5.1651] [PMID: 2272957]