Amino-aryl-carbenes: alternative ligands for transition metals?

Despite the presence of a single amino substituent, an amino-anthryl-carbene was found to behave as a strong sigma-donor weak pi-acceptor ligand toward rhodium(I) fragments.     

Diamondoid Nanostructures as sp3‐Carbon‐Based Gas Sensors

Diamondoids, sp³‐hybridized nanometer‐sized diamond‐like hydrocarbons (nanodiamonds), difunctionalized with hydroxy and primary phosphine oxide groups, enable the assembly of the first sp³‐C‐based chemical sensors by vapor deposition. Both pristine nanodiamonds and palladium nanolayered composites can be used to detect toxic NO₂ and NH₃ gases. This carbon‐based gas sensor technology allows reversible NO₂ detection down to 50 ppb and NH₃ detection at 25–100 ppm concentration with fast response and recovery processes at 100 °C. Reversible gas adsorption and detection is compatible with 50 % humidity conditions. Semiconducting p‐type sensing properties are achieved from devices based on primary phosphine–diamantanol, in which high specific area (ca. 140 m² g^?1) and channel nanoporosity derive from H‐bonding.     

A serendipitous conversion of enaminolactone nitriles with primary amines: a new synthesis of substituted 2-aminopyridine derivatives

In the course of our studies on Cerpegin analogues synthesis, a serendipitous reactivity of enaminolactone nitrile has been observed. Instead of expecting iminocerpegins, we have gained new class of substituted 2-aminopyridines. The methodology has been applied on a wide range of primary amines, as aliphatic, aromatic, heteroaromatic and also, diamines, hydrazines and chiral amines.     

Exploring the trifluoromenadione core as a template to design antimalarial redox-active agents interacting with glutathione reductase

Menadione is the 2-methyl-1,4-naphthoquinone core used to design potent antimalarial redox-cyclers to affect the redox equilibrium of Plasmodium-infected red blood cells. Exploring the reactivity of fluoromethyl-1,4-naphthoquinones, in particular trifluoromenadione, under quasi-physiological conditions in NADPH-dependent glutathione reductase reactions, is discussed in terms of chemical synthesis, electrochemistry, enzyme kinetics, and antimalarial activities. Multitarget-directed drug discovery is an emerging approach to the design of new antimalarial drugs. Combining in one single 1,4-naphthoquinone molecule, the trifluoromenadione core with the alkyl chain at C-3 of the known antimalarial drug atovaquone, revealed a mechanism for CF(3) as a leaving group. The resulting trifluoromethyl derivative 5 showed a potent antimalarial activity per se against malarial parasites in culture.     

SYNTHESIS OF MONO-AND DIALKYLPHOSPHATES BY THE REACTIONS OF HYDROXYCOMPOUNDS WITH THE PHOSPHORUS PENTAOXIDE UNDER MICROWAVE IRRADIATION

The reactions of phosphorus pentoxide with two alcohols and one phenol were performed in different conditions under microwave irradiation. The products (alkylphosphates and dialkylphosphates) were identical to those formed by classic heating and were obtained with better yields. The speed of the reaction was increased by a factor from 100 to 4000.     

Synthesis,Characterization and Theoretical Study of the Chemical Reactivity of New Cyclic Sulfamides Linked to Tetrathiafulvalene

Abstract

The synthesis of the title compounds has been carried out by condensation via a Wittig-type reaction of a pyridinium hexafluorophosphate with a phosphonate ester to give the desired (4-nitrophenyl)tetrathiafulvalene the nitro group of which was reduced to an amino group. Reaction of the amine with chlorosulfonyl isocyanate and subsequently with tert-butyl alcohol gave the corresponding open-chain sulfamide. Cyclization under basic conditions and de-protection led to 2-[4-(4′,5′-dipropyltetrathiafulvalen-4-yl)]phenyl-1,2,6-thiadiazinane 1,1-dioxide. Finally, N-alkylated and N-acylated cyclic sulfamides linked to tetrathiafulvalene were obtained. Their electron donor ability was measured by cyclic voltammetry. A detailed DFT study based on B3LYP/6–31G (d,p) of electronic properties is also presented. The calculated molecular electrostatic potential shows that, the negative charge covers the nitro and sulfamide function, while positive charge is located at the hydrogen atoms of the amine and sulfamide rings. The calculated HOMO and LUMO energy reveals that charge transfer occurs within the molecule. The chemical reactivity parameters reveal that tetrathiafulvalene 1 is highly reactive, which facilitates the desired formation of the cyclic sulfamide. The first hyperpolarizability β_tot shows that compounds 1 and 5 are good candidates as a NLO material.     

Design of amphoteric mixed oxides of zinc and Group 3 elements (Al, Ga, In): migration effects on basic features

The design of new amphoteric catalysts is of great interest for several industrial processes, especially those covering dehydration and dehydrogenation phenomena. Adsorption microcalorimetry was used to monitor the design of mixed oxides of zinc with Group 3 elements (aluminium, gallium, indium) with amphoteric character and enhanced specific surface area. Acid-base features were found to evolve non-linearly with the relative amounts of metal, and the strengths of the created acidic or basic sites were measured by adsorption microcalorimetry. A panel of bifunctional catalysts of various acid-base (amounts, strengths) and redox character was obtained. Besides, special interest was given to In-Zn mixed oxides for their enhanced basicity: this series of catalysts displays important basic features of high strength (q(diff) (SO? ads.) > 200 kJ mol(SO?)?1 in substantial amounts (1 - 2 μmol m(catalyst)?2), whose impact on efficiency or selectivity in catalytic dehydration/dehydrogenation can be valuable.     

Coordination of phosphinoboranes R2PB(C6F5)2 to platinum: an alkene-type behavior

The paucity of boron-containing heteroalkene complexes prompted us to explore the coordination of phosphinoboranes. The complexes {[R(2)PB(C(6)F(5))(2)]Pt(PPh(3))(2)} (R = Cy, t-Bu) were obtained by ethylene displacement. Spectroscopic and crystallographic data indicated symmetric side-on coordination of the phosphinoborane to Pt. Thorough analysis of the bonding situation by computational means revealed important similarities but also significant differences between the phosphinoborane and ethylene complexes.     

Potassium Fluoride on Alumina: Condensation of 1,4-Diacetylpiperazine-2,5-Dione with Aldehydes. Dry Condensation Under Microwave Irradiation. Synthesis of Albonursin and Analogues

1,4-Diacetylpiperazine-2,5-dione (1) was condensated with aldehydes (2) with KF on alumina without solvent under microwaves or in at room temperature in the presence of DMF. The reaction was stereoselective and some natural products (4a-c) like albonursin(4c) were synthesized.