Dimethyl carbonate: an environmentally friendly solvent for hydrogen peroxide (H2O2)/methyltrioxorhenium (CH3ReO3, MTO) catalytic oxidations

Environmentally friendly oxidations of various organic compounds with the hydrogen peroxide (H2O2)/methyltrioxorhenium(CH3ReO3, MTO) catalytic system have been described in dimethyl carbonate (DMC), a cheap commercially available and benign chemical having interesting solvating properties, low toxicity and high biodegradability. Oxidations proceeded with good conversions and in good yields. Spectrophotometric analysis demonstrated that the [CH3ReO(O–O)2] complex was formed in DMC and that it was stable for several days at room temperature.L'articolo è disponibile sul sito dell'editore: http://www.sciencedirect.co

High-Yielding Synthesis of Methyl Orthoformate-Protected Hydroxytyrosol and Its Use in Preparation of Hydroxytyrosyl Acetate

The new methyl orthoformate of the powerful antioxidant hydroxytyrosol (or 2- (3,4-dihydroxyphenyl)ethanol) has been synthesized by a two-step high yielding procedure. The protection stabilizes hydroxytyrosol against fast oxidation and allows both easy chromatographic purification and long term storage. The protective group is hydrolyzed over pH = 10 and below pH = 5, thus allowing the release of the active principle under physiological conditions. The use of the methyl orthoformate-protected hydroxytyrosol allows the preparation of protected hydroxytyrosyl esters, like the acetate herein reported, by selective esterification of the alcoholic function. The subsequent quantitative deprotection under non-aqueous and mild conditions affords the hydroxytyrosyl acetate in high yields

HSAB Driven N1-Alkylation of Uracil Derivatives

The lithium salts of 4-methoxy-derivatives of pyrimidinic bases undergo chemoselective N1-methylation or ethylation when treated with the appropriate alkylsulphate in dry dioxane. Under the same conditions, 4-unprotected pyrimidinic bases afford mixtures of N1-, O2- and N1,N3-alkylation products. This is explained in terms of HSAB principle.

HSAB Driven N1-Alkylation of Uracil Derivatives

The lithium salts of 4-methoxy-derivatives of pyrimidinic bases undergo chemoselective N1-methylation or ethylation when treated with the appropriate alkylsulphate in dry dioxane. Under the same conditions, 4-unprotected pyrimidinic bases afford mixtures of N1-, O2- and N1,N3-alkylation products. This is explained in terms of HSAB principle.

BICYCLO[3.3.1]NONANE APPROACH TO TRIQUINANES - FORMAL SYNTHESIS OF (+/-)-DELTA-9(12)CAPNELLENE AND (+/-)-DELTA-9(12)CAPNELLENE-8-BETA-10-ALPHA-DIOL

A new synthetic strategy for natural triquinanes is presented as a model study. Stereospecific rearrangement of the ready accessible bicyclo[3.3.1] nonanic acetoxychloride 6 gave the cis-pentalanic hydroxyaldehyde 5, which has been converted into the ketone 4 already reported as a key intermediate in some syntheses of the title capnellenes

Dosaggio di nicotina e nornicotina via GC-MS

Nell’ambito del progetto “Nuove varianti di tabacco con limitata presenza di precursori di sostanze tossiche nel fumo di tabacco” ETI (2003-2005) è stato messo a punto ed applicato un nuovo metodo di dosaggio, via GC-MS, di nicotina e nornicotina.