Adsorption and corrosion inhibition behaviour of new theophylline-triazole-based derivatives for steel in acidic medium.

The design and synthesis of a series of theophylline derivatives containing 1,2,3-triazole moieties are presented. The corrosion inhibition activities of these new triazole-theophylline compounds were evaluated by studying the corrosion of API 5 L X52 steel in 1 M HCl medium. The results showed that an increase in the concentration of the theophylline-triazole derivatives also increases the charge transference resistance ( ) value, enhancing inhibition efficiency and decreasing the corrosion process.

Visible-Light-Promoted Au to Au Oxidation in Triazol-5-ylidene Complexes.

Reaction of triazolium precursors [MIC(CH ) - H ]I (n=1-3) with potassium hexamethyldisilazane (KHMDS) and AuCl(SMe ) generates the gold(I) complexes of the type MIC(CH ) ⋅AuI. Visible light exposure of the latter complexes promotes a spontaneous disproportionation process rendering gold(III) complexes of the type [{MIC(CH ) } ⋅AuI ] I . Both the Au and Au complex series were tested in the catalytic hydrohydrazination of terminal alkynes using hydrazine as nitrogen source.

Copper(II) complexes supported by click generated mixed NN, NO, and NS 1,2,3-triazole based ligands and their catalytic activity in azide-alkyne cycloaddition.

The preparation and characterization of four new copper(ii) complexes supported by click generated mixed NN, NO, and NS 1,2,3-triazoles are reported. The four complexes display a 1 : 2 copper/ligand ratio and give monomeric units in the solid state. Crystal structures demonstrate that depending on the flexibility of the ligand NX (X = O, N, S) pendant arm, the coordination environment around the metal center can feature square planar or octahedral geometries.

Synthesis of new 1,2,3-triazole derivatives of uracil and thymine with potential inhibitory activity against acidic corrosion of steels.

Ten 1,4-disubstituted 1,2,3-triazoles were synthesized from one of 1-(azido-methyl)benzene, 1-(azidomethyl)-4-fluorobenzene, 1-(azidomethyl)-4-chlorobenzene, 1-(azidomethyl)-4-bromobenzene or 1-(azidomethyl)-4-iodobenzene, generated in situ from sodium azide and the corresponding benzyl halide, and dipropargyl uracil or dipropargyl thymine. Optimal experimental conditions were established for the conventional click chemistry. The corrosion inhibiting properties of some of these compounds, which were determined by means of an electrochemical technique, are also presented.

Synthesis of azanucleosides through regioselective ring-opening of epoxides catalyzed by sulphated zirconia under microwave and solvent-free conditions.

New azanucleosides were obtained using sulphated zirconia (ZS) as catalyst in the nucleophilic oxirane ring opening reaction of 1-allyl-3-(oxiran-2-ylmethyl) pyrimidine-2,4(1H,3H)-dione and 1-allyl-5-methyl-3-(oxiran-2-ylmethyl)-pyrimidine-2,4(1H,3H)-dione, with (S)-prolinol. The new templates were obtained with good yields following a route which exploits the reactivity of epoxides in the presence of sulphated zirconia as catalyst. The key step was carried out using microwave and solvent-free conditions and proceeds with high selectivity.

Synthesis of new pentacyclo[5.4.0.0(2,6).0(3,10).0(5,9)]undecane-8,11-dione (PCU) cyanosilylated derivatives using sulphated zirconia and hydrotalcite as catalysts in microwave-assisted reactions under solvent free conditions.

A comparison was made of the effectiveness of the functionalization reactions of pentacyclo[5.4.0.

Microwave-enhanced sulphated zirconia and SZ/MCM-41 catalyzed regioselective synthesis of beta-amino alcohols under solvent-free conditions.

A solvent-free approach for the regioselective synthesis of beta-amino alcohols in shorter reaction times and higher yields, compared to conventional heating is described. It involves microwave (MW) exposure of undiluted reactants in the presence of sulphated zirconia (SZ) or sulphated zirconia over MCM-41 (SZM) as catalyst. Both acid materials can be easily recovered and reused.

Comparative study of regioselective synthesis of beta-aminoalcohols under solventless conditions catalyzed by sulfated zirconia and SZ/MCM-41.

Sulfated zirconia and SZ/MCM-41 were used as catalysts for the synthesis of beta-aminoalcohols via epoxide aminolysis. Sulfated zirconia was prepared by sol-gel and SZ/MCM-41 was obtained by impregnation. Solid catalysts were characterized by XRD, SEM-EDS, UV-Vis, FT-IR pyridine desorption and Nitrogen physisorption.

Sulfated zirconia-catalyzed synthesis of 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) under solventless conditions: competitive multicomponent Biginelli vs. Hantzsch reactions.

The catalytic ability of ZrO(2)/SO(4)(2-) to promote solventless three-component condensation reactions of a diversity of aromatic aldehydes, urea or thoiurea and ethyl acetoacetate was studied. Products resulting from Hantzsch and/or Biginelli multi-component reactions are obtained in the presence of solid acid catalysts using the same reactants but different temperature conditions. The sulfated zirconia catalyst can be recovered and recycled in subsequent reactions with a gradual decrease of activity.