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Substituted Derivatives (substituted + derivative)
Selected AbstractsNew Substituted Derivatives of Thiourea.CHEMINFORM, Issue 49 2003IR Spectra., Synthesis 1H-NMR No abstract is available for this article. [source] C16 - and C17 -Substituted Derivatives of Pregnenolone and Progesterone as Inhibitors of 17,-Hydroxylase-C17,20 -lyase: Synthesis and Biological Evaluation.CHEMINFORM, Issue 23 2003Samer Haidar Abstract For Abstract see ChemInform Abstract in Full Text. [source] Efficient Routes to Acenaphthylene-Fused Polycyclic Arenes/Heteroarenes and Heterocyclic Fluoranthene AnaloguesEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 10 2005Kausik Panda Abstract The acenaphthenone-derived , -oxoketene dithioacetal 2 has been subjected to various [3 + 3] aromatic and heteroaromatic annulation and other heterocyclization reactions previously developed in our laboratory, providing short and efficient routes to a diverse range of known and unknown acenaphtho-annulated linear and angular PAHs, heteroaromatics and five-membered heterocycles in good yields. Thus, benzo- and naphthoannulation of 2 with various allyl and benzyl Grignard reagents afforded substituted fluoranthenes 4a,c and benzo[k]fluoranthene 8, respectively, in good yields. Similarly, the parent benzo[j]fluoranthene 15a and its substituted derivative 16b have been synthesized by base-induced conjugate 1,4-addition of arylacetonitriles to 2, followed by acid-induced cyclization of the conjugate adducts 12a,b to give 13a,b and subsequent further transformations. The adducts obtained by 1,4-addition of anions derived from acetophenone and acenaphthenone were subjected toheterocyclization in the presence of ammonium acetate to give 8-arylacenaphtho[1,2- b]pyridines 18a,b and bis(acenaphtho)-annulated pyridine 20. Heterocyclization of 2 with bifunctional nucleophiles such as 2-picolyllithium and guanidinium nitrate afforded the corresponding acenaphtho[1,2- b]quinolizinium salt 23 and acenaphtho[1,2- d]pyrimidine 24, respectively, in high yields. Finally, acenaphtho[1,2- c]-fused five-membered heterocycles such as 7-(methylthio)acenaphtho[1,2- c]thiophene (25), 7-(methylthio)acenaphtho[1,2- c]furan (27) and 7-(methylthio)acenaphtho[1,2- c]pyrrole-2-carboxylic acid (30) were obtained in good yields by subjection of 2 to Simmons,Smith reaction conditions or by treatment with dimethylsulfonium methylide or glycinate dianion. Some of these newly synthesized PAHs or fused heterocycles were subjected to Raney Ni desulfurization to furnish sulfur-free compounds. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Kinetics and mechanism of the dehydration reaction of sarcosine to a bislactame through diacyclperoxide intermediate in strong acidic mediumINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 11 2009Homayoon Bahrami The influence of substitution on the amine functional group of glycine in the permanganic oxidation of such an ,-amino acid in moderately concentrated sulfuric acid medium has been investigated. Reaction products analysis has revealed that contrary to the usual ,-amino acid oxidation product, which is an aldehyde species, a valuable compound, namely 1,4-dimethylpiperazine-2,5-dione, has been obtained as the main product via a cheap, simple, efficient, and novel method. Sarcosine has been chosen as a substituted derivative of glycine, and the kinetics and mechanism of its permanganic oxidation have been investigated using a spectrophotometric technique. Conclusive evidence has proven delayed autocatalytic activity for Mn(II) in this reaction, analogous to some ,-amino acids. It has been revealed that such activity can show up when a certain concentration ratio of Mn(II) to sarcosine is built up in the medium, which we call the "critical ratio." The magnitude of the latter ratio depends on the sulfuric acid concentration. Considering the "delayed autocatalytic behavior" of Mn(II) ions, rate equations satisfying observations for both catalytic and noncatalytic routes have been presented. The reaction shows first-order dependence on permanganate ions and sarcosine concentrations in both catalytic and noncatalytic pathways, and apparent first-order dependence on Mn2+ ions in catalytic pathways. The correspondence of pseudo-order rate constants of the catalytic and noncatalytic pathways to Arrhenius and Eyring laws has verified "critical ratio" as well as "delayed autocatalytic behavior" concepts. The activation parameters associated with both pathways have been computed and discussed. Mechanisms for both catalytic and noncatalytic routes involving radical intermediates as well as a product having a diketopiperazine skeleton have been reported for the first time. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 689,703, 2009 [source] Synthesis, Characterization and Electrochemistry of the Novel Dawson-Type Tungstophosphate [H4PW18O62]7, and First Transition Metal Ions DerivativesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2004Israel-Martyr Mbomekalle Abstract Following the synthesis of pure [H4PW18O62]7, (PW18), its derivatives monosubstituted with M (M = MoVI, VIV, VV, MnII, FeIII, CoII, NiII CuII and ZnII) were obtained. All compounds were characterized by elemental analysis, IR, UV/visible and 31P NMR spectroscopy. Their cyclic voltammetry properties were studied as a function of pH and systematically compared with those of their analogs derived from the symmetrical species, [P2W18O62]6,(P2W18). Comparison of the two unsubstituted precursors revealed that the merging of the first two waves of the monophosphate occurred in a less acidic medium than for the diphosphate. The observations point to the higher basicity of the reduced forms of PW18 compared with those of P2W18. The fingerprint pattern observed for ,2 -P2W17M derivatives in media of pH = 3 consisted of the splitting of the third W redox system into two one-electron closely spaced waves which is in contrast to the same system in ,1 -P2W17M. This peculiarity was also obtained for several of the present ,2 -PW17M systems in media of pH = 3 and confirmed that ,2 -substituted derivatives were indeed formed. The absence of this peculiar behavior in some other derivatives is consistent with smooth variations of acid-base properties from one derivative to the next. The electrocatalytic properties of all the compounds are illustrated by the reduction of nitrite by reduced PW18 and of nitrate by reduced ,2 -PW17Cu. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Ring Contraction of 3,6-Dihydro-2H -thiopyrans to Thiolanes by an Iodo-Oxyacylation ReactionEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 1 2004Andre C. B. Lucassen Abstract Reaction of functionalized 3,6-dihydro-2H -thiopyrans with N -iodosuccinimide in the presence of carboxylic acids results in the stereospecific formation of poly-functionalised thiolanes in good yield. The formation of these thiolanes is believed to proceed through either a nucleophilic or an electrophilic pathway leading to 4,5- cis -substituted derivatives. The use of unsymmetrical 2,2-substituted 3,6-dihydro-2H -thiopyrans gave mixtures of isomers that could be separated in several cases. From a 3-substituted thiopyran a 2,2,3,4,5-pentasubstituted thiolane was obtained. Attempts to use alcohols as external nucleophiles were unsuccessful with NIS, NBS, and N -bromoacetamide. Iodo-azidination with in situ generated IN3 was also unsuccessful. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] X-Ray Structure Analyses of syn/anti -Conformers of N -Furfuroyl-, N -Benzoyl-, and N -Picolinoyl-Substituted (2R)-Bornane-10,2-sultam DerivativesHELVETICA CHIMICA ACTA, Issue 8 2008Karolina Koszewska Abstract The synthesis and the X-ray structure of the three new N -(arylcarbonyl)-substituted derivatives 2a,2c of (2R)-bornane-10,2-sultam are presented and discussed. Direct comparison of the solid-state analyses shows that the dipole-directed SO2/CO anti- /syn- conformations may be very sensitive to weak electronic/electrostatic repulsions of the heteroatom lone pairs. The optimum interactions are reached when the lone pair of the , -positioned heteroatom is oriented in the O(3)C(11)N(1) plane. Such rare syn -conformations may be observed with at least up to 1.8,kcal/mol higher energy as compared to their ground states. Additionally, these anti/syn- conformations are also very sensitive to external influences such as, for example, the crystal-packing forces. [source] Novel Chemical Transformations of TenoxicamHELVETICA CHIMICA ACTA, Issue 8 2005Kristóf Kóczián Both N - and O -substituted derivatives of the anti-inflammatory drug tenoxicam (=,4-hydroxy-2-methyl- N -(pyridin-2-yl)-2H -thieno[2,3 -e],[1,2]thiazine-3-carboxamide 1,1-dioxide; 1) were synthesized, and various chemical transformations were investigated. Both selective hydrolysis and reaction of 1,- N -methyltenoxicam (5) with a variety of N-nucleophiles were performed (Scheme,1). Also, five new 4- O -acyl derivatives 10 were prepared as potential prodrugs (Scheme,2). The 4-chloro derivatives of 1 and its analog 8 could be successfully transformed into the novel tetra- and tricyclic ring systems 12 and 13, respectively, the latter being a conformationally restricted 1,5-diaryl-pyrazole designed as a potential COX-2 inhibitor. [source] Oxidative behavior and relative reactivities of some unsaturated compounds towards hexachloroiridate(IV) in perchloric acid mediumINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 7 2002Kalyan K. Sen Gupta The kinetics of the oxidation of styrene, cinnamic acid, and some of their substituted derivatives by hexachloroiridate(IV) in dimethyl formamide,water mixtures and in the presence of perchloric acid have been investigated. The reactions appear to proceed via the formation of an unstable intermediate 1:1 complex between iridium(IV) and the substrate, followed by the decomposition of the complex in the rate-determining step. Correlation with , yielded , values of ,4.0 and ,3.5 which suggests the formation of a cationic intermediate in the rate-determining step of the reaction. Subsequent cleavage of the carbon,carbon bond yielded the product aldehydes. Thermodynamic and activation parameters associated with the equilibrium and the rate-determining steps were also evaluated. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 411,417, 2002 [source] Colorimetric investigation of the reaction between p -phenylendiamine and meta -substituted derivatives of benzene on a model supportINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 3 2010M. Scalzo J. Cosmet. Sci., 60, 429,436 (July/August 2009) Synopsis The aim of this work was the employment of colorimetric techniques in the analysis of the color formed, on a proteic substrate, by the reaction between p -phenylendiamine and some meta -substituted benzene derivatives in the presence of hydrogen peroxide and in media at different pH values. In particular we investigated the chromatic variations that take place on the substrate in dependence on different reaction conditions. The obtained results show that for each couple of reagents the colorimetric data, namely the reflectance of the formed color, change considerably with the pH of the reaction medium and demonstrate how this parameter can be considered a good descriptor of the composition of the formed pigment. [source] Synthesis and characterization of 4,6-dichloroindole-based radioligands for imaging the glycine site of the NMDA ion channelJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 2 2002R. N. Waterhouse Abstract To provide effective PET or SPECT ligands for the glycine binding site of the NMDA ion channel, we have synthesized and characterized in vitro four substituted derivatives of the potent glycine site antagonist 3-[2-[(phenylamino)carbonyl]ethenyl]-4,6-dichloroindole-2-carboxylic acid (Ki=3.0 nM). These new ligands contain groups amenable to labeling with C-11 for PET, or I-123 for SPECT. In vitro analysis of these compounds revealed that placement of a methoxy group at either the ortho or para position of the phenylaminocarbonyl group significantly reduced receptor affinity (Ki=74.0±8.1 and 26.5±4.9 nM, respectively), as did placement of an iodine at the para position (Ki=60.4±8.2 nM). However, the meta -methoxy derivative (4b) maintained high affinity (Ki=4.8±0.9 nM) for the glycine site and was therefore labeled with carbon-11 by reacting the corresponding desmethyl derivative with [11C]methyl iodide. Radiochemical yields of 14±10% (EOS), and high specific activity (1.2±0.5 Ci/,mol (EOS, n=7)) were realized, and the product was prepared in a sterile saline solution suitable for in vivo use. Copyright © 2002 John Wiley & Sons, Ltd. [source] Correlation of the rates of solvolysis of benzoyl chloride and derivatives using extended forms of the Grunwald,Winstein equation,JOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 12 2002Dennis N. Kevill Abstract Available specific rates of solvolysis at 25,°C of benzoyl chloride and four para -substituted derivatives for which both NT and YCl values are tabulated were analyzed using the extended (two-term) Grunwald,Winstein equation. The ionization pathway with appreciable nucleophilic solvation of the incipient carbocation observed for the p -methoxy derivative is accompanied by increasingly important regions of dominant operation of an addition,elimination pathway as the Hammett , value for the substituent increases. Accordingly, for the p -nitro derivative only the 97% HFIP data point deviates from the addition,elimination correlation. Correlations of the specific rates of solvolysis of 2,6-dimethylbenzoyl chloride are improved by incorporation of a term governed by the aromatic ring parameter (I). Copyright © 2002 John Wiley & Sons, Ltd. [source] Complete assignment of 1H and 13C NMR spectra of ,-phenylsulfinyl- N -methoxy- N -methylpropionamide and some p -substituted derivativesMAGNETIC RESONANCE IN CHEMISTRY, Issue 3 2009Nelson L. C. Domingues Abstract The complete assignment of the 1H and 13C NMR spectra of the diastereomeric pairs of some ,-arylsulfinyl-substituted N -methoxy- N -methylpropionamides with the substituents methoxy, methyl, chloro, nitro is reported. Copyright © 2008 John Wiley & Sons, Ltd. [source] 4-(2-Hydroxyphenyl)-2-phenyl-2,3-dihydro-1H -1,5-benzodiazepine and the 2-(2,3-dimethoxyphenyl)-, 2-(3,4-dimethoxyphenyl)- and 2-(2,5-dimethoxyphenyl)-substituted derivativesACTA CRYSTALLOGRAPHICA SECTION C, Issue 7 2007Carlos A. Escobar The 1,5-benzodiazepine ring system exhibits a puckered boat-like conformation for all four title compounds [4-(2-hydroxyphenyl)-2-phenyl-2,3-dihydro-1H -1,5-benzodiazepine, C21H18N2O, (I), 2-(2,3-dimethoxyphenyl)-4-(2-hydroxyphenyl)-2,3-dihydro-1H -1,5-benzodiazepine, C23H22N2O3, (II), 2-(3,4-dimethoxyphenyl)-4-(2-hydroxyphenyl)-2,3-dihydro-1H -1,5-benzodiazepine, C23H22N2O3, (III), and 2-(2,5-dimethoxyphenyl)-4-(2-hydroxyphenyl)-2,3-dihydro-1H -1,5-benzodiazepine, C23H22N2O3, (IV)]. The stereochemical correlation of the two C6 aromatic groups with respect to the benzodiazepine ring system is pseudo-equatorial,equatorial for compounds (I) (the phenyl group), (II) (the 2,3-dimethoxyphenyl group) and (III) (the 3,4-dimethoxyphenyl group), while for (IV) (the 2,5-dimethoxyphenyl group) the system is pseudo-axial,equatorial. An intramolecular hydrogen bond between the hydroxyl OH group and a benzodiazepine N atom is present for all four compounds and defines a six-membered ring, whose geometry is constant across the series. Although the molecular structures are similar, the supramolecular packing is different; compounds (I) and (IV) form chains, while (II) forms dimeric units and (III) displays a layered structure. The packing seems to depend on at least two factors: (i) the nature of the atoms defining the hydrogen bond and (ii) the number of intermolecular interactions of the types O,H...O, N,H...O, N,H...,(arene) or C,H...,(arene). [source] Antioxidant Activity of Newly Synthesized 2,7-DiazaphenothiazinesARCHIV DER PHARMAZIE, Issue 5 2010Beata Morak-M, odawska Abstract A series of 19 derivatives of 2,7-diazaphenothiazine was synthesized and evaluated for their antioxidant activity bearing in mind the structural similarity with "classical" phenothiazines several of which are considered powerful antioxidants. Among the new derivatives that inhibited in vitro Fe2+/ascorbate-induced lipid peroxidation of rat liver microsomal membranes, several exhibited significant antioxidant activity with IC50 values in the range of 64,125 ,M. Although N -substitution led to a variable degree of antioxidant activity, the latter appears to correlate with the lipophilicity (expressed as clogP values) of the substituted derivatives. Reduced lipophilicity may also explain the relatively lower protection offered by these derivatives against lipid peroxidation when compared to their "classical" phenothiazine counterparts. Thus, modification of the phenothiazine structure by a substitution of two benzene rings with pyridine rings to form this new type of azaphenothiazines does not enhance antioxidant activity, although it retains it. [source] Probing Novel 1-Aza-9-oxafluorenes as Selective GSK-3, InhibitorsCHEMMEDCHEM, Issue 1 2008Burkhardt Voigt Dr. Abstract Within the histopathology of Alzheimer's disease (AD) certain hallmarks are beeing observed. The occurance of protein deposits belong to such characteristic features. Such deposits can be found extracellular as ,-amyloid (A,) plaques and intracellular as neurofibrillary tangles (NFTs). In the search for novel AD therapeutics it became of great interest to investigate the formation of NFTs and their contribution to the AD symptomatic. NFTs consist of hyperphosphorylated tau protein. Within the phosphorylation process of tau protein two kinases are of great importance: cyclin dependent kinase 5 (cdk5) and its truncated regulatory subunit p25 and glycogen synthase kinase 3, (GSK-3,). The role of both kinases within the NFT formation process is still under debate. To better understand the pathophysiological process highly selective inhibitors of both kinases are of value. Known inhibitors lack the necessary selectivity. We developed novel 1-aza-9-oxafluo-renes as selective GSK-3, inhibitors. Structure,activity relationships of a series of 4-phenyl substituted derivatives are discussed. Variation of the 3-side chain led to selective carbonyl amide derivatives with selectivity factors of more than 100 at the tested ATP competitor concentrations. Such selectivities permit specific investigation of the role of GSK-3, within the NFT formation processes. [source] | ||||||||||||||||||||||