a mild and green method has been developed for the preparation of coumarins derivatives through the one-pot reactions. in our study,various phenols and ethyl acetoacetate compound in which we used silica-supported boron sulfonic acid [sio2/b(so4h)3] as a new, highly efficient and tri-functional inorganic brønsted acid catalyst were processed under solvent-free condition and thermal. the catalys...

Heparin-based anticoagulants are drugs of choice in the therapy and prophylaxis of thromboembolic diseases. Idraparinux is a synthetic anticoagulant pentasaccharide based on the heparin antithrombin-binding domain. In the frame of our ongoing research aimed at the synthesis of sulfonic acid-containing heparinoid anticoagulants, we elaborated a modular pathway to obtain a series of idraparinux-a...

The etherification of glycerol with tert-butyl alcohol in the liquid phase, over different sulfonic acid functionalized zeolites, has been studied. The reaction was carried out using microwaves as a way of heating, measured at autogenous pressure and without any solvent. Dealuminated HY and HZSM-5 zeolites by acid treatment were functionalized with two different organosilica precursors: 3-merca...

In Sri Lanka young inflorescence of Caryota urens L (Family: Arecaceae) is tapped for sweet sap that is then used for preparation of fermented beverage and sweeteners. In folkloric, these products are claimed to have health benefits. However, as yet biological activities of C. urens sap have not been scientifically investigated. Recent scientific investigations reported the nutritional value of...

Two highly efficient protocols for the production of bis-coumarins under solvent-free conditions have been introduced. The reaction of 4-hydroxycoumarin (2 eq.) with arylaldehydes (1 eq.) using phthalimide-N-sulfonic acid (PhtSA) or isatin-N-sulfonic acid (IsSA), as solid-acid catalysts, afforded the mentioned compounds with good to excellent yields in short times.Briefly, we have introduced tw...

Inflammatory bowel disease is associated with inducible nitric oxide synthase (iNOS) expression, oxidative and nitrosative stress, and leukocyte infiltration in the colon. Here, we investigate the effects of the selective iNOS-inhibitor (S)-2-amino-(1-iminoethylamino)-5-thiopentanoic acid (GW274150) on the development of experimental colitis induced by dinitrobenzene sulfonic acid. When compare...

The ability of certain species of bacteria and yeasts that usually contaminate fresh palm sap to induce the formation of the carcinogen dimethylnitrosamine from suitable precursors (trimethylamine, dimethylamine, nitrate, and nitrite) was investigated in vitro under neutral and acid pH conditions. In the incubation media containing cell suspensions of each species of test organism, namely, Aero...

Polymer-electrolyte-membrane fuel cells (PEM-FCs) are considered as the most promising fuel cell technique for applications like automobiles or stationary power supplies. State-of-the-art separator materials in PEM-FCs are commonly sulfonic acid functionalized polymers, like the perfluorinated polymer Nafion. These materials show the required high proton conductivity only at high degree of hydr...