2,4,5-Triaryl-imidazoles have found application in medicinal chemistry due to their interesting photophysical properties (high fluorescence quantum yields and large Stokes shift's), for example as ligands for Pt(II) complexes, as probes of DNA structure or new therapeutic agents due to their capacity to bind or interact with DNA. Recently we reported the synthesis of several 2,4,5-tri(heteroaryl)imidazoles which could be used in diverse optical applications (e.g. nonlinear optics, fluorimetric chemosensors, OLEDs and DNA intercalators). Metallic cations can be complexed through N, O and S donor atoms in amino acids, at the main and side chains, and in aromatic heterocycles, whereas anion coordination, based on hydrogen bonding and electrostatic interactions, can arise from amino acid side and main chain OH and NH groups, or from NH groups in heterocycles. Therefore, the insertion of suitable heterocyclic systems at the side chain of natural amino acids can add extra functionality to the amino acid. We now report the synthesis and photophysical characterization of novel 2,4,5-triarylimidazolyl-alanines and the interaction study with biologically important ions such as F-, OH-, Cu2+, Fe3+ and Hg2+, through spectrophotometric and spectrofluorimetric titrations.  

(2-(pyrazin-2-yl)aminmethylenehydrazono)-thiazolidin-4-one, HPzAm4DHotaz, and (2-(pyrazin-2-yl)aminmethylenehydrazono)-3-methylthiazolidin-4-one, PzAm4Motaz have been prepared by the reaction of thiosemicarbazones with chloroacetic acid in presence of triethylamine in toluene using a microwave assisted synthesis and a conventional method, at reflux temperature. While the conventional method carried out other side products as triazoles and thiadiazoles, the cyclization of the thiosemicarbazones using microwave irradiation favours the obtaining of the tiazolidinones as only product and gave better yields, shorter times and any side products were formed

The imidazole nucleus is of great importance in medicinal chemistry because it plays an important role in biochemical processes as structural component of several biomolecules (for example, histidine, vitamin B12, nucleotides, histamine and biotin), and also has various pharmacological activities (anti-HIV, anti-convulsant, calcium antagonist, inhibitors of thromboxane A2 synthase, antihistaminic, anti-parkinsonism and MAO inhibitor).1 Besides their application in medicinal chemistry, 2,4,5-tri(hetero)aryl-imidazoles are also a versatile class of compounds in materials chemistry due to their optoelectronic properties. Earlier studies reported by us showed that the optical and thermal properties of these derivatives could be tuned by substitution of aryl groups at positions 2, 4 and 5 by 5-membered heterocycles giving rise to innovative applications of these p-conjugated systems in nonlinear optics (e.g. second harmonic generators (SHG)), chemosensors, OLEDs and DNA intercalators.2 In this communication, we describe the synthesis of new tri-(hetero)arylimidazoles, functionalized with different heterocycles, to evaluate the photophysical properties of the resulting compounds. The imidazole derivatives 2a-d were obtained in good yields by reaction of diphenylethanedione with an heterocyclic aldehyde 1a-d in the presence of ammonium acetate in acetic acid at reflux. The new derivatives were characterized by the usual techniques and a detailed photophysical study was undertaken.

In this work the polar Diels-Alder reactions between 2- and 3-nitrobenzothiophenes derivatives and different dienes, such as 2-methyl-1,3-butadiene and 1-trimethylsilyloxy-1,3-butadiene are studied. Molecular solvent and protic ionic liquids are employed as reaction media. A very strong electron-acceptor group such as nitro group, push the electrophilic character of these heterocyclic compounds. Moreover, this substituent is easily extruded under thermal conditions make this reaction sequence a simple method of organic compound´s families with heteroatom rings preparation.

Quinoline is a heterocyclic scaffold of paramount importance to human race. Quinolines and their derivatives occur in numerous natural resources. Compounds containing quinoline structure are widely used as antiasthmatic, antimalarials, anti-viral, anti-inflammatory, antibacterials, antifungals, and anticancer (1). Among quinoline derivatives, tetrahydroquinolines (THQs) are an important structural subunit of natural and synthetic products and many THQs derivatives exhibit interesting biological and pharmaceutical activities (2). Many quinoline derivatives have shown anti-cholinesterase activity and can be potential agents for treatment of Alzheimer disease (3-5).In the present study we have synthesized 7 derivatives of THQs with different patterns of substituent using the Povarov reaction in presence of Lewis acid, all compounds was characterized by 1H-NMR, 13C-NMR and Mass Spectra, and evaluated as potentials inhibitors of acetylcholinesterase.

Substituted S-(1-benzofuran-2 (3H)-one-3-yl) isothiuronium bromides are derived from cyclic lactame coumaran-2-one, which are prepared by dehydratation of (2-hydroxyphenyl)acetic acid. Thus prepared lactam is further brominated to position 3, where a good leaving group is needed. In next step 3-bromocoumaran-2-one reacts with different substituded thioureas  in the meaning of nucleophilic substitution of atom bromine to atom sulfur and give substituted S-(1-benzofuran-2 (3H)-one-3-yl) isothiuronium bromide, which was obtained as a solid in good yield. These relatively unstable salts were characterized by 1H and 13C NMR spectra, melting point and elemental analysis. Isothiuronium salts are transformed in base conditions and give substituted 5 - (2-hydroxyphenyl)-2-imino-1 ,3-thiazolidine -4-ones. In this rearrangement is applied acid-base catalysis under very mild conditions. The rearrangement proceeds even at physiological pH, which may have potential importance in the use of these compounds as prodrugs. Next, the kinetics and the mechanism of the rearrangement of N-(4-methoxyphenyl)-S‑(2-oxo-2,3-dihydro-1-benzofurane-3‑yl) isothiuronium bromide to 5‑(2‑hydroxyphenyl)-2-[(4-methoxyphenyl)imino]-1,3-thiazolidin-4-on is studied in aqueous buffers at 25 °C and ionic strength  I = 1 mol×l–1 under pseudo-first order conditions.

Abstract: The Et3N-promoted reaction of (E)-3-aryl-2-cyanoacrylamides (arylmethylenecyanoacetamides) with 1-cyanoacetyl-3,5-dimethylpyrazole was thoroughly studied. It was found that either triethylammonium 4-aryl-3,5-dicyano-6-oxo-1,4,5,6-tetrahydropyridine-2-olates 1 (salts of Guareschi imides) or their oxidation products – triethylammonium 4-aryl-3,5-dicyano-6-oxo-1,6-dihydropyridine-2-olates 2 were formed, depending on the nature of substituents in the 3-aryl fragment of starting acrylamides. Thus, when Ar = ortho-, meta-substituted phenyl or hetaryl such as 2-furyl, 3-thienyl etc., only Guareschi imides salts 1 were obtained in good to excellent yields. In the case of para-substituted or unsubstituted phenyl, pyridine-2-olates 2 were isolated as major products due to fast oxidation of Guareschi intermediates. The influence of reaction conditions and the nature of the base on the structure of final products is discussed.

A faciles ynthetic methodology of novel azolyl, azinyl and azepinyl phosphonates ascyclic α-aminophosphonates was described. Chromonyl α-aminophosphonates,γ-pyranyl and γ-pyridinyl phosphonates were also prepared. The methodologydepends on reaction of 6-methyl-3-formylchromone, nitrogen and carbon nucleophiles in thepresence of diethyl phosphite in one-pot three component under solvent-freeconditions. The products were evaluated for their antimicrobial activities andantioxidant properties.

Five ionic liquids derived from pyridinium cation polysubstituted with different alkyl chains were synthesized. Their thermal properties (phase transition and decomposition temperatures) and physical properties (density, speed of sound, refractive index and viscosities) were evaluated. The effect of the number of alkyl chains, their length and their position on the pyridinium ring over the studied physical and thermal properties is also analyzed and discussed.

Tripodal topology of tris-imidazolium salts of isocyanuric acid derivatives is a field that has not been studied in detail. A strategy based on 1,3,5-tris(2-hydroxyethyl)-1,3,5-triazinane-2,4,6-trione was designed. This compound was converted into 3,3',3''-((2,4,6-trioxo-1,3,5-triazinane-1,3,5-triyl)tris(ethane-2,1-diyl))tris(1-methyl-1H-imidazol-3-ium) chloride in two steps through its trihalide derivative in good yields. This opens a new line of research for anionic receptors and polycationic ionic liquids.