SYNTHESIS OF SOME NEW 3-ARYLOXYMETHYL- 4-PHENYL-5-(N-SUBSTITUTED CARBOXAMIDOMETHYLTHI0)-S-TRIAZOLES

Abstract

3-Aryloxymethyl-4-phenyl-5-mercapto-s-triazoles (I_a-c) have been synthesized and reacted with N-chloroacetyl derivatives of aromatic and/or heterocyclic amines to yield 5-(N-aryl/heterocyclyl)-carboxamidomethyl thio-s-triazole derivatives 2_a-o and 3_a-o respectively. Reaction of I_a-u with ethyl chloroacetate gave the corresponding esters 4_a-c which were reacted with hydrazine hydrate to give hydrazides 5_a-c. Condensation of 5_a-c with aromatic aldehydes gave Schiff s bases 6_a-u with on cycloaddition reaction with thioglycolic acid yielded 4-thiazolidinones 7_a-g. Some of these compounds were screened in vitro for their antibacterial activities.     

Radioprotective and Antitumor Activity of Some Novel Amino Acids and Imidazoles Containing Thieno[2,3-d]pyrimidine Moiety

A variety of novel thieno[2,3-d]pyrimidine derivatives, comprising amino acids 3a–l, imidazothieno-pyrimidines 4A, 4b–h, and 7, were obtained via the reaction of 4-chloro-5,6-dimethylthieno[2,3-d]pyrimidine 1 with a variety of reagents. The structures of these compounds were confirmed by microanalysis, IR, ¹H NMR, and mass spectrometry. Some of the obtained compounds showed promising radioprotective and antitumor activities.     

SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF SOME NEW PYRIDO[3′,2′:4,5]THIENO[3,2-d]- PYRIMIDINE DERIVATIVES

5-Acetyl-3-amino-4-aryl-6-methylthieno[2,3-b]pyridine-2-carboxamides (1a, b) were reacted with aromatic aldehydes or with some cycloalkanones to give the corresponding tetrahydropyridothienopyrimidinone derivatives 2a–f and 4a–d . The reaction of compound 1b with urea and/or carbon disulfide has been carried out and their products were identified. Some representative compounds were screened in vitro for their antimicrobial activities.     

Synthesis and Properties of a Chelating Resin Containing a Salicylaldimine Group

Abstract

A phenol-formaldehyde polymer, poly(salicylaldehyde 3,5-diylmethylene) was synthesized and characterized. A chelating ionexchange resin was obtained by reacting the polymer with nbutylamine. The chelation characteristics of the chelate-forming resin was studied by a batch equilibration technique. The resin showed fast rates of metal ion uptake and was found to selectively chelate Cu²⁺ and Cd²⁺ ions with capacities up to 3.56 mmol/g over a pH range of 5–8.     

Unexpected Formation of O-Acylhydroxamate from the Oxidation of a Dihydroisoquinoline Imine

The reaction of 3,3-dimethyl-7-nitro-3,4-dihydroisoquinoline 1 with m-chloroperbenzoic acid (m-CPBA) mainly yielded oxaziridine and nitrone, with their selectivities being dependent on the solvents. The reaction with 2.5 equivalents of m-CPBA gave small amounts of oxaziridines and hydroxamic acids as well as isolated O-acylhydroxamate compounds.     

A mild, expedient, one-pot trifluoromethanesulfonic anhydride mediated synthesis of N-arylimidates

The direct transformation of various secondary amides into N-arylimidates via mild electrophilic amide activation with trifluoromethanesulfonic anhydride (Tf₂O) in the presence of 2-chloropyridine (2-ClPyr) is described. Low-temperature amide activation followed by C-O bond formation with 2-naphthol provides the desired N-arylimidates in short overall reaction times. In contrast, reaction with oxindole proceeds via formation of a C-C bond to give 1-(1H-indol-2-yl)naphthalene-2-ol.     

4-Carbomethoxybenzaldehyde as a highly sensitive pre-column fluorescence derivatization reagent for 9,10-phenanthrenequinone

9,10-Phenanthrenequinone (PQ) is harmful environmental pollutant that is detected in airborne particulates. The measurement of PQ in the air should be necessary to evaluate the potential adverse effects of PQ on human health. We have recently developed a determination method for PQ based on the fluorescence derivatization of PQ using benzaldehyde and ammonium acetate as a reagent. In this study, in order to obtain more sensitive and selective fluorescence derivatization reaction, we measured the fluorescence of the reaction mixture of PQ with 21 kinds of aromatic aldehydes in the presence of ammonium acetate. Among the tested aldehydes, 4-carbomethoxybenzaldehyde was found to be the best reagent in regard to fluorescence intensity and emission wavelength maximum. Based on the fluorescence derivatization with 4-carbomethoxybenzaldehyde, a highly sensitive chromatographic method was developed for the determination of PQ with the detection limit (S/N=3) of 1.2 fmol/injection.     

Robust outer synchronization between two complex networks with fractional order dynamics

Synchronization between two coupled complex networks with fractional-order dynamics, hereafter referred to as outer synchronization, is investigated in this work. In particular, we consider two systems consisting of interconnected nodes. The state variables of each node evolve with time according to a set of (possibly nonlinear and chaotic) fractional-order differential equations. One of the networks plays the role of a master system and drives the second network by way of an open-plus-closed-loop (OPCL) scheme. Starting from a simple analysis of the synchronization error and a basic lemma on the eigenvalues of matrices resulting from Kronecker products, we establish various sets of conditions for outer synchronization, i.e., for ensuring that the errors between the state variables of the master and response systems can asymptotically vanish with time. Then, we address the problem of robust outer synchronization, i.e., how to guarantee that the states of the nodes converge to common values when the parameters of the master and response networks are not identical, but present some perturbations. Assuming that these perturbations are bounded, we also find conditions for outer synchronization, this time given in terms of sets of linear matrix inequalities (LMIs). Most of the analytical results in this paper are valid both for fractional-order and integer-order dynamics. The assumptions on the inner (coupling) structure of the networks are mild, involving, at most, symmetry and diffusivity. The analytical results are complemented with numerical examples. In particular, we show examples of generalized and robust outer synchronization for networks whose nodes are governed by fractional-order Lorenz dynamics.     

The effect of annealing process on the physical properties of La1−xNaxMnOy

The effect of Na doping and annealing time on the structure, electrical properties, magnetoresistance and thermopower properties has been investigated in perovskite La_1−xNa_xMnO_y (x=0.025, 0.075 and 0.1) systems. La_1−xNa_xMnO_y crystallizes in a single-phase rhombohedral structure. It is observed a simultaneous occurrence of the ferromagnetic to paramagnetic state and metallic to insulating state. In the meanwhile, a large negative magnetoresistance with low applied magnetic field is observed. In addition, ρ(T) curves for Na-doped samples exhibit another broad transition T_ms2 below T_ms. Such double peak behavior in the ρ(T) curve interpreted by the electronic inhomogeneity in the samples. The sign of S changes from positive to negative depending on composition. The values of Seebeck coefficient are small (in the microvolt range).     

YOYO as a Dye to Track Penetration of LK15 DNA Complexes in Spheroids: Use and Limits

To elucidate the reasons underlying the poor penetration of non-viral vectors in tissues, relating transport properties to physico-chemical parameters of vectors may be crucial. These properties can be influenced by the presence of multiples labels that are used. Therefore utilizing a vector with minimum of labels preferably not more than one is important to studying penetration in tissues. The cell impermeant bisintercalating dye YOYO-1 was found suitable to both monitor the formation of complexes between DNA and an amphipathic peptide LK15 and, to track their penetration in HCT116 spheroids by confocal microscopy. The results revealed a limited decrease of fluorescence ascribed to the high affinity of YOYO-1 to bind DNA. The residual fluorescence of complexes can be exploited to monitor penetration into spheroids, after correction for YOYO-1 attenuation, and to revealing hyaluronidase-induced reduced binding. Hence high affinity dyes such as YOYO-1 with inefficiently quenched fluorescence may be important to establish a relation between novel medicines characteristics and penetration in tissues.