Unitus DSpace The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. http://http://dspace.unitus.it:80 2013-05-19T02:40:42Z 2013-05-19T02:40:42Z A Convenient and Safe O-Methylation of Flavonoids with Dimethyl Carbonate (DMC) Bernini, Roberta Crisante, Fernanda Ginnasi, Maria Cristina http://hdl.handle.net/2067/1296 2011-06-28T15:04:00Z 2010-12-31T23:00:00Z Title: A Convenient and Safe O-Methylation of Flavonoids with Dimethyl Carbonate (DMC) Authors: Bernini, Roberta; Crisante, Fernanda; Ginnasi, Maria Cristina Abstract: Dietary flavonoids exhibit beneficial health effects. Several epidemiological studies have focused on their biological activities, including antioxidant, antibacterial, antiviral, anti-inflammatory and cardiovascular properties. More recently, these compounds have shown to be promising cancer chemopreventive agents in cell culture studies. In particular, O-methylated flavonoids exhibited a superior anticancer activity than the corresponding hydroxylated derivatives being more resistant to the hepatic metabolism and showing a higher intestinal absorption. In this communication we describe a convenient and efficient procedure in order to prepare a large panel of mono- and dimethylated flavonoids by using dimethyl carbonate (DMC), an ecofriendly and non toxic chemical, which plays the role of both solvent and reagent. In order to promote the methylation reaction under mild and practical conditions, 1,8-diazabicyclo[5.4.0]undec-7- ene (DBU) was added in the solution; methylated flavonoids were isolated in high yields and with a high degree of purity. This methylation protocol avoids the use of hazardous and high toxic reagents (diazomethane, dimethyl sulfate, methyl iodide). Description: L'articolo è disponibile sul sito dell'editore: www.mdpi.com 2010-12-31T23:00:00Z An efficient and selective epoxidation of olefins with novel methyltrioxorhenium/(fluorous ponytailed) 2,2′-bipyridine catalysts Saladino, Raffaele Ginnasi, Maria Cristina Collalto, Daniela Bernini, Roberta Crestini, Claudia http://hdl.handle.net/2067/1795 2011-06-29T15:42:40Z 2009-12-31T23:00:00Z Title: An efficient and selective epoxidation of olefins with novel methyltrioxorhenium/(fluorous ponytailed) 2,2′-bipyridine catalysts Authors: Saladino, Raffaele; Ginnasi, Maria Cristina; Collalto, Daniela; Bernini, Roberta; Crestini, Claudia Abstract: Novel complexes between methyltrioxorhenium (MTO) and bis(fluorous- ponytailed) 2,2′bipyridines (bpy-Fn) were synthesized and used for the oxidation of alkenes with hydrogen peroxide under fluorous catalysis. High conversions and yields of the corresponding epoxides were obtained. Description: L'articolo è disponibile sul sito dell'editore: http://www.onlinelibrary.wiley.com 2009-12-31T23:00:00Z