BACKGROUND Isocyanates are some of the leading occupational causes of respiratory disorders, predominantly asthma. Adequate exposure monitoring may recognize risk factors and help to prevent the onset or aggravation of these aliments. Though, the biomonitoring appears to be most suitable for exposure assessment, the sampling time is critical, however. In order to settle the optimal time point f...

A new series of water compatible primary-tertiary diamine catalysts derived from natural primary amino acids bearing a hydrophobic side chain have been synthesized. These new primary-tertiary diamine-Brønsted acid conjugates bifunctional organocatalysts efficiently catalyzes the asymmetric direct syn selective cross-aldol reaction of different protected hydroxyacetone with various aldehydes in ...

Atropisomeric biaryl aldehydes undergo diastereoselective condensation with (-)-ephedrine and with a proline-derived diamine, with selectivity highly dependent on solvent, temperature and reaction conditions. Levels of thermodynamic control up to 5:1 may be obtained by heating the diamine with the aldehyde in a sealed tube. Alternatively, crystallisation-induced dynamic transformation allows is...

The Schiff base compounds N,N'-bis[(E)-quinoxalin-2-ylmethylidene]propane-1,3-diamine, C(21)H(18)N(6), (I), and N,N'-bis[(E)-quinoxalin-2-ylmethylidene]butane-1,4-diamine, C(22)H(20)N(6), (II), crystallize in the monoclinic crystal system. These molecules have crystallographically imposed symmetry. Compound (I) is located on a crystallographic twofold axis and (II) is located on an inversion ce...

The role of copper in pig kidney diamine oxidase has been probed by examining the effects of potential Cu(II) ligands on the spectroscopic and catalytic properties of the enzyme. In the presence of azide and thiocyanate, new absorption bands are evident at 410 nm (epsilon = 6300 M-1 cm-1) and 365 nm (epsilon = 3000 M-1 cm-1), respectively. These bands are assigned as ligand-to-metal charge-tran...

The copper-catalyzed N-arylation of amides, i.e., the Goldberg reaction, is an efficient method for the construction of products relevant to both industry and academic settings. Herein, we present mechanistic details concerning the catalytic and stoichiometric N-arylation of amides. In the context of the catalytic reaction, our findings reveal the importance of chelating diamine ligands in cont...

Two components, two steps: Control over the mechanochromic luminescence (MCL) of a dibenzofuran-based bis(1-pyrenylmethyl)diamine was achieved using two-component donor-acceptor approach. Wide-range MCL with solid-state emission wavelength shift 340 nm and two-step that can respond to mechanical stimuli different intensity were realized for mixtures composed this diamine variety non-MCL accepto...

Polymer-supported chiral 1,2-diamine derivatives have been prepared. The polymers containing free 1,2-diamine moiety were applied to enantioselective hydrogenation catalyst by combination with RuCl2-BINAP complex. Asymmetric hydrogenation of aromatic ketones was performed by means of the polymeric catalyst derived from these polymers to give the chiral secondary alcohols with high ee in quantit...

Chemical agents that cleave HIV genome can be potentially used for anti-HIV therapy. In this report, the cleavage of the upper stem-loop region of HIV-1 TAR RNA was studied in a variety of buffers containing organic catalysts. trans-(±)-Cyclohexane-1,2-diamine was found to cleave the RNA with the highest activity (31%, 37°C, 18 h). Cleavage of the RNA in trans-(±)-cyclohexane-1,2-diamine buffer...