The synthesis of 4‐trifluoromethyl‐2‐methyl[phenyl]pyrimidines and the corresponding tetrahydro derivatives from the cyclo‐condensation reaction of β‐alkoxyvinyl trifluoromethyl ketones 1a‐d with acetamidine or benzamidine hydrochloride, is reported. For the cyclo‐condensation of 1a‐d with acetamidine and benzamidine hydrochloride, two methods were tested: 1 M solution of sodium hydroxide (method A) and sodium alkoxide/alcohol (method B). Depending on the structure of the β‐alkoxyvinyl trifluoromethyl ketones and the reactions conditions, pyrimidines or tetrahydropyrimidines or a mixture of both compounds were obtained.

Recebido em 5/8/09; aceito em 16/11/09; publicado na web em 24/3/10 FATTY ESTER CONTENT DETERMINATION IN SOYBEAN METHYL BIODIESEL BY GAS CHROMATOGRAPHY USING ETHYL OLEATE AS INTERNAL STANDARD. A method for ester content determination in soybean methyl biodiesel was studied, using ethyl oleate as internal standard. A biodiesel sample was analyzed and had its purity estimated as 92.8%. Method accuracy was evaluated by comparison with the result obtained via EN14103, with a relative difference of 0.1%. Repetitivity and intermediate precision were estimated as 2 and 1.5%, respectively.

The stereoselective synthesis of novel multifunctionalized cyclopropanes from γ,δ-epoxy malonates and amines mediated by LiCl under mild conditions was carried out. This domino reaction involves the initial cyclopropanation via intramolecular ring-opening of γ,δ-epoxy malonates through the cooperative catalysis of LiCl (acting as a Lewis acid) and a Brønsted base (a primary or, in selected cases, a secondary amine). The sequential events consisted of lactonization and aminolysis of the lactone ring, which ultimately furnished cyclopropanecarboxamides with different substitution patterns in good isolated yields. In all cases, a quaternary stereogenic center could be perfectly assembled, with a single diastereoisomer being obtained. This method proceeds with high atom economy, is remarkably modular and operationally simple, and tolerates a variety of functional groups. The involvement of readily available starting materials, the broad scope, and the use of a sustainable solvent (methanol or ethanol) at ambient temperature make this domino process highly effective. A reaction mechanism is proposed on the basis of the experimental observations involving the preparation and reactivity of cyclopropylidene lactones as possible intermediates of the domino process.

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The synthesis of small spherical palladium(II) iodide nanoparticles is reported for the first time. The formation of the particles by ligand exchange, in the presence of poly(vinyl pyrrolidone) in aqueous medium at room temperature, was investigated by in situ time‐resolved synchrotron‐based SAXS and XANES/EXAFS analysis. These new nanomaterials exhibit a double catalytic role in an aryl alkenylation chemical reaction, working without a base or ligand, in aqueous milieu. There is strong experimental evidence to suggest that the mechanism follows a single‐electron transfer (SET) pathway with the participation of iodide as a radical promoter and the palladium atoms as activator of the alkene moiety. This new protocol could evolve into a broadly applicable radical reaction for the functionalization of alkenes.