Antonio De Nino

Highly efficient and versatile acetylation of alcohols catalyzed by cerium(III) triflate

Cerium(III) triflate is a powerful catalyst for the acetylation of alcohols. The reaction works well for a large variety of simple and functionalized alcohols, without isomerisation of chiral centres. Changes of hydroxyl protective groups are possible in a one-pot procedure. The catalyst can be easily recycled.

Virtual freezing of the hemiacetal–aldehyde equilibrium of the aglycones of oleuropein and ligstroside present in olive oils from Carolea and Coratina cultivars by ionspray ionization tandem mass spectrometry

The composition of the equilibrium between aldehydes and hemiacetals was evaluated by ionspray ionization tandem mass spectrometry. The methanolic extracts of virgin olive oil from Carolea and Coratina cultivars contain a complex mixture of hydroxytyrosol (3) and tyrosol (4) derivatives (5, 6) characterized by the presence of aldehyde moieties in equilibrium with their hydrated form (8) or with the corresponding methanol hemiacetals 9 and 10. The equilibrium was frozen by droplet evaporation, thus allowing the structure determination of each component. The formation of the decarboxylated species 11-14, reported previously, was not observed.

Direct Identification of Phenolic Glucosides from Olive Leaf Extracts by Atmospheric Pressure Ionization Tandem Mass Spectrometry

Pneumatically assisted electrospray (or ionspray) coupled with liquid chromatography was applied to the identification of the phenolic glucoside content of olive leaf directly from the crude extracts. The mass spectra of the positive ions provide insights into the composition of the phenolic constituents. Oleuropein, ligstroside and a disaccharide containing the hydroxytyrosol moiety were found in olive leaf of Olea europea L. cv. Cassanese and their structures were thoroughly determined by tandem mass spectrometry.

Characterization of cassanese olive cultivar through the identification of new trace components by ionspray tandem mass spectrometry

Pneumatically assisted electrospray (ionspray) coupled with liquid chromatography was applied in the identification of antioxidants present in traces in the leaves of Olea europea L. cv. Cassanese, a typical olive tree from the northeastern part of Calabria region in Italy. The structures of these potential biomarkers were evaluated with reference to established mass spectrometric rules or, in one case, by matching the tandem mass spectrum of the unknown with that of an authentic sample obtained by synthesis. Copyright

Deprotection of t-butyldimethylsilyl ethers promoted by cerium(IV) triflate

t-Butyldimetylsilyl ethers are mildly cleft by catalytic amounts of cerium(IV) triflate. Dependence from water amount was observed.

Per-O-acetylation of sugars catalyzed by Ce(OTf)3

Ce(OTf)3 is proposed as a valuable Lewis acid promoter in the per-O-acetylation reactions of sugars. The Ce(OTf)3 is an environmentally friendly catalyst, used in very low percentage, and can be recovered after reaction and used without significant loss of activity.

9-Vinylguanine: an easy access to aza-analogs of 2′,3′-dideoxyguanosine

Abstract 9-Vinylguanine, obtained for the first time and fully characterised by X-ray analysis, allows access to aza-analogues of 2′,3′-dideoxynucleosides through cycloaddition processes.

Mild and efficient method for the cleavage of benzylidene acetals by using erbium (III) triflate

Er(OTf)3 is proposed as new efficient Lewis acid catalyst in a mild deprotection protocol of benzylidene derivatives. In a modified procedure, where acetic anhydride is used as the reaction solvent, the simultaneous cleavage of the benzylidene acetal and the peracetylation of the substrates is obtained in quantitative yields and very short reaction times.

Synthesis and biological evaluation of diastereoisomerically pure N,O-nucleosides.

Several N,O-nucleosides have been synthesized in good yields by direct 1,3-dipolar cyclization methodology, in the absence of solvent. A remarkable cis stereoselectivity (de 98%) was observed by tuning the substituents on the nitrone moiety. A good number of these N,O-nucleosides have been evaluated for cytotoxic activity against selected cellular lines. Some of the tested compounds have proven to be potential antiproliferative drugs.

Erbium(III) Chloride: a Very Active Acylation Catalyst

Erbium(iii) chloride is a powerful catalyst for the acylation of alcohols and phenols. The reaction works well for a large variety of simple and functionalized substrates by using different kinds of acidic anhydrides (Ac2O, (EtCO)2O, (PriCO)2O, (ButCO)2O, and (CF3CO)2), without isomerization of chiral centres. Moreover, the catalyst can be easily recycled and reused without significant loss of activity.