Objective: Present research work is carried out for rapid development of some biological active new heterocyclic moieties.
Method: A novel series of 3-substituted-1-[1-(toluene-4-sulfonyl)-1H-benzoimidazol-2-yl]-propen-1-one (3a-3j) were synthesized by tosylation of benzimidazole chalcones (2a-2j) using ultrasound in lesser time with higher yields. All the synthesized compounds were characterized by Elemental analysis, IR spectra, 1H, 13C NMR and Mass spectroscopy. The newly synthesized compounds were screened for their α-glucosidases and antibacterial activity.
Result: Biological evaluation of the compounds (3a-3j) revealed that most of them are good α-glucosidases inhibitors and possess ...view middle of the document...
, 1995; Robinson et al., 2002). However, to maintain the blood glucose levels as close to normal as possible has become most challenging in the management of diabetic or obese patients (Lebovitz et al., 1998). Several epidemiological studies support the view that postprandial hyperglycemia has one of the most significant treatment modalities in diabetes management and also appeared as an independent risk factor for cardiovascular disease (Arshag et al., 1999).
The α, β- unsaturated ketones (chalcones) are biosynthetic products of Shikimate pathway, considered as the precursors of flavonoids and isoflavonoids as well as their diverse array of pharmacological activities (Star et al., 1971). Natural and synthetic chalcone derivatives have been largely studied owing to their broad spectrum of biological activities such as anti-inflammatory, anti-leishmanial, anti-invasive, anti-tuberculosis, anti-fungal, anti-malarial, anti-tumor, anti-oxidant, anti-HIV properties (Nielsen et al., 1998; Ronghshi et al., 1995; Sylvie et al., 1998; Lin et al., 2002; Nowakowska et al., 2007). Recently, aminated and sulphonamide derived chalcones were reported as the modest to potent glucosidase inhibitors, which can be easily obtained with the simple protocol (Najafian et al., 2011; Seo et al., 2005).
At the present time, application of ultrasound (sonochemistry) has become an exciting field of research. The chemical effects of ultrasound are diverse and include substantial improvements in both stoichiometric and catalytic chemical reactions. Ultrasonic irradiation accelerates the reactivity million fold and many synthetically useful reactions were successfully accomplished (Einhom et al., 1989). As compared to conventional conditions, viz. strong base and long reaction time, the ultrasonic irradiation procedure is milder and more conventional leading to higher yields in shorter reaction time (Mason, 1991).
Herein, in continuation to extend our research on benzimidazole derived chalcones with glucosidase inhibitors (Gangadhar et al., 2013), we report the ultrasound prompted synthesis of novel 3-substituted-1-[1-(toluene-4-sulfonyl)-1H-benzimidazol-2-yl]-propen-1-ones.
MATERIALS AND METHODS
Reagent and analytical grade chemicals were used without further purification. Completion of the reaction was monitored by thin layer chromatography (TLC) using glass plates coated with silica gel. Experiments under ultrasound irradiation were carried out in “Enertech” ultrasonic Bath (Model No. EN030US). The reaction flask was located in the maximum energy area in the ultrasonic bath and the addition or removal of water controlled the temperature of the water bath. IR spectra were obtained on PerkinElmer Frontier 91579 FT-IR spectrophotometer using ATR attachment. All 1H and 13C NMR (300 and 75 MHz respectively) spectra were recorded on Bruker Avance spectrometer where samples were run in CDCl3 with 1% TMS as internal standard. Chemical shifts are expressed as δ. Mass...