Electrochemical Study of Butyl-Pyrene Nitrobenzoate Derivatives Trapped on MWCNT Nanostructured Electrodes

In the scope of our studies tending to find new nanostructured electrodic platforms containing nitroaromatic compounds (NACs) capable of generating in situ electrocatalytic redox couples, we synthesized and electrochemically studied three related 4-(pyren-1-yl)-butyl-substituted nitrobenzoates (2-NBPy, 3-NBPy and 4-NBPy). The design of the compounds is based on a combination of a) an adsorptive tail (-butyl-pyrene) capable of interacting via π-π stacking with the MWCNT nanostructured electrodes and b) nitroaromatic compounds (NACs) capable of electrochemically activating to form a RNHOH/NO redox couple trapped on the nanostructured electrodic platform. Morphological and structural analyses of the nanostructured interfaces were performed by SEM and WAXS/SAXS analysis. All of the NBPy compounds trapped on the nanostructured electrodic platform were susceptible to reduction, generating the corresponding hydroxylamine derivative. The order of ease of reduction for the nitrocompounds is 4-NBPy > 2-NBPy > 3-NBPy. After electrochemical activation, all compounds generated an RNHOH/NO redox mediator couple with the following order of stability of the mediator couple: 2-NBPy > 3-NBPy > 4-NBPy. For the 2-NBPy and 3-NBPy derivatives, excellent stability of the couple was observed, and a decrease in the peak current of 6% was observed after 60 minutes.

The YfkO Nitroreductase from Bacillus Licheniformis on Gold-Coated Superparamagnetic Nanoparticles: Towards a Novel Directed Enzyme Prodrug Therapy Approach

The bacterial nitroreductase NfnB has been the focus of a great deal of research for its use in directed enzyme prodrug therapy in combination with the nitroreductase prodrug CB1954 with this combination of enzyme and prodrug even entering clinical trials. Despite some promising results, there are major limitations to this research, such as the fact that the lowest reported Km for this enzyme far exceeds the maximum dosage of CB1954. Due to these limitations, new enzymes are now being investigated for their potential use in directed enzyme prodrug therapy. One such enzyme that has proved promising is the YfkO nitroreductase from Bacillus Licheniformis. Upon investigation, the YfkO nitroreductase was shown to have a much lower Km (below the maximum dosage) than that of NfnB as well as the fact that when reacting with the prodrug it produces a much more favourable ratio of enzymatic products than NfnB, forming more of the desired 4-hydroxylamine derivative of CB1954.

Efficient access to unprotected primary amines by iron-catalyzed aminochlorination of alkenes

Primary amines are essential constituents of biologically active molecules and versatile intermediates in the synthesis of drugs and agrochemicals. However, their preparation from easily accessible alkenes remains challenging. Here, we report a general strategy to access primary amines from alkenes through an operationally simple iron-catalyzed aminochlorination reaction. A stable hydroxylamine derivative and benign sodium chloride act as the respective nitrogen and chlorine sources. The reaction proceeds at room temperature under air; tolerates a large scope of aliphatic and conjugated alkenes, including densely functionalized substrates; and provides excellent anti-Markovnikov regioselectivity with respect to the amino group. The reactivity of the 2-chloroalkylamine products, an understudied class of amphoteric molecules, enables facile access to linear or branched aliphatic amines, aziridines, aminonitriles, azido amines, and homoallylic amines.

Synthesis of tri-functionalized MMP2 FRET probes using a chemo-selective and late-stage modification of unprotected peptides

A polymeric FRET probe for the detection of MMP2 was prepared using a new N-hydroxylamine derivative of lysine, which was successfully incorporated into the natural peptide sequence by solid phase peptide synthesis, allowing dual orthogonal ligations of the fully unprotected peptides.

Physico-chemical characterization of mixed-ligand complexes of Mn(III) based on the acetylacetonate and maleic acid and its hydroxylamine derivative

Two new Mn(III) mixed-ligand complexes with two acetylacetonate (acac) ligands and one maleate ligand and its hydroxylamine derivative of the general formula [Mn(C5H7O2)2L] were prepared. Their structure was established by using elemental analysis, FTIR and UV/VIS spectroscopic methods, as well as magnetic measurement. Replacement of the acetylacetonate ligand by the corresponding acid ligand has been confirmed in Mn(III) acetylacetonate. Based on the obtained experimental data and literature indications, structural formulae to these compounds were assigned.