First chemoenzymatic synthesis of organoselenium amines and amides

A series of organoselenium amines have been synthesized and submitted to the enzymatic kinetic resolution by acetylation mediated by CAL-B (Novozym 435) to give the corresponding chiral amides in an enantiomerically pure form. After evaluating the appropriate lipase, solvent, temperature,and lipase/substrate ratio in the kinetic resolution, the chiral organoselenium amides were obtained with enantiomeric excess of up to 99%. (C) 2008 Elsevier Ltd. All rights reserved.

Antimicrobial Activity of Ethylenediaminedisuccinate Metal Complexes

It is shown that metal complexes of the biodegradable ligand ethylenediaminedisuccinic acid (edds) present antimicrobial activity towards fungi and bacteria. [Cd(edds)], in particular, is more toxic than free Cd2+ to Aspergillus niger, behaving as a `Trojan Horse` in the facilitated delivery of the toxic metal into the fungus.

Uncovering false positives on a virtual screening search for cruzain inhibitors

Some unexpected promiscuous inhibitors were observed in a virtual screening protocol applied to select cruzain inhibitors from the ZINC database. Physical-chemical and pharmacophore model filters were used to reduce the database size. The selected compounds were docked into the cruzain active site. Six hit compounds were tested as inhibitors. Although the compounds were designed to be nucleophilically attacked by the catalytic cysteine of cruzain, three of them showed typical promiscuous behavior, revealing that false positives are a prevalent concern in VS programs. (C) 2007 Elsevier Ltd. All rights reserved.

Structure-activity relationships of hypervalent organochalcogenanes as inhibitors of cysteine cathepsins V and S

A new series of organotelluranes were synthesized and investigated, and the structure-activity relationships in cysteine proteases inhibition were determinated. It was possible to identify the relevance of structural components linked to the reactivity of these compounds as inhibitors. For example, dibromo-organotelluranes showed to be more reactive than dichloro-organotelluranes towards cysteine cathepsins V and S. Besides, no remarkable enantio-selectivity was verified. In general the achiral organotelluranes were more reactive than the chiral congeners against cysteine cathepsins V and S. A reactivity order for organochalcogenanes and cysteine cathepsins was proposed after the comparison of the inhibitory potencies of organotelluranes with the related organoselenanes. (C) 2011 Elsevier Ltd. All rights reserved.

Influence of Reaction Conditions on Synthesis of PAni/MnO(2) Composites

An investigation of the parameters as aniline: MnO(2) and temperature on synthesis of polyaniline/MnO(2) composites was performed. The composites were chemically prepared in H(2)SO(4) media using different aniline: MnO(2) ratios at 0 degrees C. After the ratio optimization, the syntheses were performed at 20 degrees C. The polyaniline/MnO(2) composites were characterized by scanning electron microscopy (SEM), ultraviolet-visible, near infrared and infrared spectroscopic techniques. Composites obtained with a uniform, homogeneous and thicker coating of polyaniline films under oxide was considered as the best condition for synthesis.

Removal of Zn(2+) from Electroplating Wastewater Using Modified Wood Sawdust and Sugarcane Bagasse

This paper describes the preparation of new adsorbents derived from sugarcane bagasse and wood sawdust (Manilkara sp.) to remove zinc (II) ions from electroplating wastewater. The first part deals with the chemical modification of sugarcane bagasse and wood sawdust, using succinic anhydride to introduce carboxylic acid functions into the material. The obtained materials (modified sugarcane bagasse MB2 and modified wood sawdust MS2) were then characterized by infrared spectroscopy (IR) and used in adsorption experiments. The adsorption experiments evaluates Zn(2+) removal from aqueous single metal solution and real electroplating wastewater on both batch and continuous experiments using fixed-bed columns prepared in laboratorial scale with the obtained adsorbents. Adsorption isotherms were then developed using Langmuir model and the Thomas kinetic model. The calculated Zn(2+) adsorption capacities were found to be 145 mg/g for MS2 and 125 mg/g for MB2 in single metal aqueous solution, whereas for the industrial wastewater these values were 61 mg/g for MS2 and 55 mg/g for MB2.