Showing papers on "Pyrazoline published in 2003"
TL;DR: The hypsochromic shift in the emission of DAP nanoparticles was identified as originating from the pronounced decrease in the Stokes shift due to the restraint of vibronic relaxation and the configuration reorganization induced by the increased intermolecular interaction.
Abstract: Organic nanoparticles of 1,3-diphenyl-5-(2-anthryl)-2- pyrazoline (DAP) ranging in average diameters from 40 to 160 nm were prepared through the reprecipitation method. The average diameters of the particles were controlled by variation of the aging time. We found that DAP nanoparticles exhibit the size-dependent optical properties. The absorption transitions of the nanoparticles at the lower-energy side experience a bathochromic shift with an increase in the particle size as a result of the increased intermolecular interactions, while the higher-energy bands of anthracene split possibly due to the electronic coupling between the pyrazoline ring of one molecule and the anthracene moiety of the neighboring molecule. Most interestingly, the nanoparticle emission in the blue light region from pyrazoline chromophore shifts to shorter wavelengths with an increase in the particle size, accompanied with a relatively gradual dominance of the emission at about 540 nm from an exciplex between the pyrazoline ring of...
261 citations
TL;DR: A water soluble pyrazoline derivative in vivo is evaluated as a potential intracellular pH probe and density functional calculations were used to probe the electronic structure and energy ordering of the emissive and the electron-transfer state.
Abstract: A series of donor-substituted 1,3,5-triaryl-2-pyrazoline fluorophores were structurally characterized by X-ray analysis, and their photophysical properties studied by steady-state absorption and emission spectroscopy. The photoinduced electron-transfer thermodynamics of the derivatives was estimated on the basis of the spectroscopic data and redox potentials of the fluorophores. The aryl substituents in the 1- and 3-position of the pyrazoline ring influence the photophysical properties of the fluorophores in distinctly different ways. The excited-state equilibrium energy ΔE00 is primarily influenced by changes of the substituent in the 1-position, whereas the reduction potential of the fluorophore is essentially determined by the 3-aryl group. Density functional calculations were used to probe the electronic structure and energy ordering of the emissive and the electron-transfer state. The results from the computational analysis agree qualitatively well with the experimental data. In addition, we have eva...
159 citations
146 citations
TL;DR: In this article, the structures of all new compounds have been established by extensive NMR spectroscopic studies, including bis(pyrazoles) 5e,f bearing hydroxyphenyl substituents and bis(chromones) 6c,d with hydrazine hydrate.
59 citations
TL;DR: The preparation of pyrazoline and isoxazoline derivatives with traceless solid-phase sulfone linker strategy is described and a library of 12 pyrazolines and is oxazolines was synthesized.
47 citations
TL;DR: In this paper, a synthetic route for incorporating pyrazoline derivatives as proline surrogates in constrained X-Pro peptidomimetics was developed for the synthesis of dipeptide building blocks having either a six or seven-membered-ring annulated onto the pyridine moiety, as well as for the asymmetric synthesis of analogs having substituents on N-terminal side of the building block.
27 citations
TL;DR: The photodenitrogenation of chiral trisubstituted 1-pyrazolines has been studied by laser flash photolysis andoretical calculations support a mechanistic pathway involving a trimethylene radical as intermediate that rapidly evolves to the corresponding cyclopropane derivative.
Abstract: The photodenitrogenation of chiral trisubstituted 1-pyrazolines has been studied by laser flash photolysis. These experiments have permitted the detection of two transients that have been assigned, for each pyrazoline, to the trimethylene-type diradical resultant from the extrusion of nitrogen (lifetime tau = 0.1-0.8 micros) and to the pyrazoline triplet (tau < 9 ns), respectively. The efficiency of the photosensitization process has been evaluated by determination of the corresponding quenching rate constant in each instance. Theoretical calculations support a mechanistic pathway involving a trimethylene radical as intermediate that rapidly evolves to the corresponding cyclopropane derivative. The cyclopropane ring-closure is predicted to be faster than rotation around the C-C bond, thus accounting for the observed stereospecificity.
21 citations
Patent•
19 Feb 2003
TL;DR: Novel pyridyl and pyrimidinyl substituted pyrazole and pyrazoline compounds and compositions for use in therapy were presented in this paper, where they were used in therapy.
Abstract: Novel pyridyl and pyrimidinyl substituted pyrazole and pyrazoline compounds and compositions for use in therapy.
16 citations
TL;DR: In this article, three push-pull type azo dyes, 4 ′ -{[(2-hydroxylethyl)methyl]amino}-4-nitroazobenzene (compound I), 1-[4-(4 ′)-nitrophenyl)-azophenyl]-3,5-biphenyl-2-pyrazoline(compound II) and 1-[ 4-(4 Ã ¼ Ã Ã − n)-azphenyl]- 3,3 Ã -trifluoromet
11 citations
TL;DR: A series of 1-aryl-2,2-bis-(1,8-naphthyridin-2-yl)ethenes have been synthesized from 2-aminonicotinaldehyde via α-(1 8 naphthryidin]-banzalacetones 3 as discussed by the authors.
Abstract: A series of 1-aryl-2,2-bis-(1,8-naphthyridin-2-yl)ethenes 4, 5-aryl-3-methyl-4-(1,8-naphthyridin-2-yl)-1-phenyl-2-pyrazolines 5, 5,6-dihydro-6-aryl-4-methyl-5-(1,8-naphthyridin-2-yl)-2-thioxopyrimidines 6 and 2,3-dihydro-2-aryl-4-methyl-3-(1,8-naphthyridin-2-yl)-1H-1,5-benzodiazepines 7 have been synthesized from 2-aminonicotinaldehyde 1 via α-(1,8-naphthyridin-2-yl) banzalacetones 3. The benzalacetones 3 have been readily obtained by the condensation of 1 with 3-arylideneacetylacetones 2. These compounds have been characterized on the basis of elemental analyses, IR, 1 H NMR and MS. The compounds 4, 5 and 6 have been screened for their antibacterial activity.
8 citations
Journal Article•
TL;DR: A series of 1-aryl-2,2-bis-(1,8-naphthyridin-2-yl)ethenes have been synthesized from 2-aminonicotinaldehyde via α-(1 8 naphthryidin]-banzalacetones 3 as mentioned in this paper.
Abstract: A series of 1-aryl-2,2-bis-(1,8-naphthyridin-2-yl)ethenes 4, 5-aryl-3-methyl-4-(1,8-naphthyridin-2-yl)-1-phenyl-2-pyrazolines 5, 5,6-dihydro-6-aryl-4-methyl-5-(1,8-naphthyridin-2-yl)-2-thioxopyrimidines 6 and 2,3-dihydro-2-aryl-4-methyl-3-(1,8-naphthyridin-2-yl)-1H-1,5-benzodiazepines 7 have been synthesized from 2-aminonicotinaldehyde 1 via α-(1,8-naphthyridin-2-yl) banzalacetones 3. The benzalacetones 3 have been readily obtained by the condensation of 1 with 3-arylideneacetylacetones 2. These compounds have been characterized on the basis of elemental analyses, IR, 1 H NMR and MS. The compounds 4, 5 and 6 have been screened for their antibacterial activity.
Patent•
02 Jan 2003
TL;DR: In this paper, a compound selected from compounds represented by the following formula (1) (which include 3-phenyl-2-pyrazoline derivatives and 3- phenyl-tetrahydropyridazine derivatives) and pharmacologically acceptable salts thereof, an agent is provided which can activate glutamic acid transporter and which is useful for prevention and/treatment of cerebral ischemia (cerebral infarct and brain edema), amyotrophic lateral sclerosis (ALS), etc., all caused by glutamic acids toxicity.
Abstract: Using a compound selected from compounds represented by the following formula (1) (which include 3-phenyl-2-pyrazoline derivatives and 3-phenyl-tetrahydropyridazine derivatives) and pharmacologically acceptable salts thereof, an agent is provided which can activate glutamic acid transporter and which is useful for prevention and/treatment of cerebral ischemia (cerebral infarct and brain edema), amyotrophic lateral sclerosis (ALS), etc., all caused by glutamic acid toxicity.
Journal Article•
TL;DR: A series of pyrazolines 3a-j and isoxazoles 4a-k have been synthesized by the action of hydrazine hydrate and hydroxylamine hydrochloride respectively on 1-aryl-3-(2'-chloro-7'-methylquinolin-3'-yl)-2-propen-1-ones as discussed by the authors.
Abstract: A series of pyrazolines 3a-j and isoxazoles 4a-k have been synthesized by the action of hydrazine hydrate and hydroxylamine hydrochloride respectively on 1-aryl-3-(2'-chloro-7'-methylquinolin-3'-yl)-2-propen-1-ones 2 while the compounds 2 are prepared by the condensation of 2-chloro-7-methyl-quinoline-3-carboxaldehyde 1 with different aromatic ketones. All the compounds have been characterized on the basis of elemental analyses and spectral data. The compounds have been screened for their in vitro antifungal and antibacterial activities.
TL;DR: In this article, the interaction of 3,5-dichloro-2-pyridylhydrazine with α,β-unsaturated carbonyl compounds leads to 1,3,5-,5-disubstituted Δ2-pyrazolines.
Abstract: The interaction of 3,5-dichloro-2-pyridylhydrazine with α,β-unsaturated carbonyl compounds leads to 1-(3,5-dichloro-2-pyridyl)-3,5-disubstituted Δ2-pyrazolines. It was shown that N-(3,5-dichloro-2-pyridyl)hydrazones of the corresponding aldehydes and ketones are formed as intermediates. Condensation of the hydrazine mentioned above with α,β-diketones gives 1,3,5-trisubstituted pyrazoles, but with acetoacetic ester a 1,3-disubstituted pyrazol-5-one containing a 3,5-dichloropyridyl residue is obtained.
TL;DR: The 1,3-dipolar cycloaddition of diazomethane to levoglucosenone was found to occur regio-and stereoselectively to form optically active 9,11-dioxa-4,5-diazatricyclo[6.2.1.02,6]undec-4-en-7-one.
Abstract: The 1,3-dipolar cycloaddition of diazomethane to levoglucosenone was found to occur regio- and stereoselectively to form optically active 9,11-dioxa-4,5-diazatricyclo[6.2.1.02,6]undec-4-en-7-one. Levoglucosenone was found to react with methyldiazoacetate to give the 2:1 adduct.
TL;DR: Two azo-containing polymers with pyrazoline group (polymers II and III) have been synthesized and their reversible optical storage properties tested in comparison with electron donor and acceptor substituted azobenzene-containing polymer I as mentioned in this paper.
Journal Article•
TL;DR: In this article, ultrasonic velocity and density measurements on 3-hydroxy-3-nitro-5-chlorophenyl)-5-(2-furyl)-Δ 2 -pyrazoline and its complexes with Fe(II), Ni (II), Co (II) and Cr (II)) in acetone as a solvent, have been carried out at 298.5 K.
Abstract: Ultrasonic velocity and density measurements on 3-(2-hydroxy-3-nitro-5-chlorophenyl)-5-(2-furyl)-Δ 2 -pyrazoline and its complexes with Fe (II), Ni (II), Co (II), Cu (II), Mn (II) and Cr (II) in acetone as a solvent, have been carried out at 298.5 K. Different acoustic properties like apparent molar volume, apparent molar compressibility, inter-molecular free-length, etc. have been determined. The parameters so obtained have been interpreted in terms of solute-solvent and solute-solute interactions.
Patent•
20 Feb 2003TL;DR: In this paper, the claimed liquid formulations contain an organic acid and a branched mono- or di-alcohol and the added alcohol improves the storage stability of the liquid formulations.
Abstract: The claimed liquid formulations contain an organic acid and a branched mono- or di-alcohol. The addition of the alcohol improves the storage stability of the liquid formulations.
TL;DR: The reaction between 4-(4-methylphenyl)but-3-en-2-one and aminoguanidine produced an unexpected product of formula C(12)H(15)N(3)O, consisting of a carboxamide moiety joined to a substituted pyrazoline ring at one of the N atoms.
Abstract: The reaction between 4-(4-methylphenyl)but-3-en-2-one and aminoguanidine produced an unexpected product of formula C(12)H(15)N(3)O, consisting of a carboxamide moiety joined to a substituted pyrazoline ring at one of the N atoms. The pyrazoline ring adopts a flat-envelope conformation and the substituted phenyl ring is oriented almost perpendicular to the heterocycle. The carbonyl O atom has partial anionic character as a result of the transfer of pi density from the two adjacent sp(2) N atoms and is involved in an intermolecular hydrogen bond with the amide group.
TL;DR: A series of 1,3,5-triphenyl-2-pyrazoline (TPP) nanocrystals were prepared by the reprecipitation method in this paper, and the electronic transitions of TPP nanocrystal have been studied using both absorption and f...
Abstract: A series of 1,3,5-triphenyl-2-pyrazoline (TPP) nanocrystals were prepared by the reprecipitation method. The electronic transitions of TPP nanocrystals have been studied using both absorption and f...
TL;DR: Protoporphyrin reacts with diazomethane to give pyrazolines which at long wavelength (approximately 630 nm) extrude nitrogen to give the corresponding cyclopropyl derivatives as discussed by the authors.
Abstract: Protoporphyrin reacts with diazomethane to give pyrazolines which at long wavelength (approximately 630 nm) extrude nitrogen to give the corresponding cyclopropyl derivatives.
Journal Article•
TL;DR: In this paper, a one pot procedure was developed to prepare the derivatives of 1,3,5 triarylpyrazoles (3a-3g) by tetrakispyridine cobalt(Ⅱ) dichromate (TPCD) promoted dehydrogenation of 1.3, 5 triaryl pyrazolines to their aromatic forms.
TL;DR: In both crystal structures, despite there being a large number of accessible hydrogen-bond acceptor sites, only one H atom from the NH(2) group is involved in hydrogen bonding; the molecules are assembled into discrete centrosymmetric dimers via a pair of nearly linear N-H.
Abstract: The two title compounds, C 13 H 18 N 8 and C 17 H 20 N 8 .0.5H 2 O, possess similar molecular shapes, with the pyrazoline moiety and s-triazine ring located approximately in one plane, and the imidazole or benzimidazole ring nearly perpendicular to the s-triazine nucleus. In both crystal structures, despite there being a large number of accessible hydrogen-bond acceptor sites, only one H atom from the NH 2 group is involved in hydrogen bonding; the molecules are assembled into discrete centrosymmetric dimers via a pair of nearly linear N-H...N hydrogen bonds.
Patent•
10 Jul 2003
TL;DR: In this paper, an organic light emitting compound containing a pyrazoline group and an organic electroluminescence device using the compound are provided, wherein the compound emits the blue light of a high quality, shows high efficiency and heat resistance and an improved lifetime.
Abstract: PURPOSE: An organic light emitting compound containing a pyrazoline group and an organic electroluminescence device using the compound are provided, wherein the compound emits the blue light of a high quality, shows high efficiency and heat resistance and an improved lifetime. CONSTITUTION: The organic light emitting compound is represented by the formula 2, wherein X is at least one aryl group combined with nitrogen, having C18-C50; n is an integer of 2-4; and R1 and R2 are identical or different each other and are H, SO2R, CO2R, SR, OR, NR2, CN, a halogen atom or Ph-R3 (wherein R3 is H, SO2R, CO2R, SR, OR or NR2, and R is an alkyl group of C1-C10). The organic electroluminescence device comprises a first electrode having a high work function; a second electrode having a low work function; and at least one organic compound layer which is placed between the first and second electrodes and comprises the organic compound of the formula 2. Preferably the organic compound layer is an organic light emitting layer and/or a hole transport layer.
TL;DR: In this paper, a tandem cascade reaction of one molecule of alkyl azide and four molecules of methyl vinyl ketone gives a heterocyclic compound having an 1,4-diazepine fused to a pyrazoline and spiro-linked to a dihydropyran.
Abstract: Tandem cascade reaction of one molecule of alkyl azide and four molecules of methyl vinyl ketone gives a heterocyclic compound having an 1,4-diazepine fused to a pyrazoline and spiro-linked to a dihydropyran. The tandem cascade reaction is composed of an intermolecular [3+2] dipolar cycloaddition to give a triazoline, an isomerization to a diazo compound, another intermolecular [3+2] dipolar cycloaddition to give a pyrazoline, a Michael addition, dehydration, and a [4+2] cycloaddition.
Patent•
01 Oct 2003
TL;DR: In this article, a method for making hydrazine hydrate which consists in purging heterocyclic compounds of the pyrazoline family to prevent coloration was proposed.
Abstract: The invention concerns a method for making hydrazine hydrate which consists in hydrolyzing methyl ethyl ketone azine to obtain hydrazine hydrate and methyl ethyl ketone, characterised in that it consists in purging heterocyclic compounds of the pyrazoline family to prevent coloration of the hydrazine hydrate.
Patent•
30 Jun 2003
TL;DR: In this article, a kind of 1,3-aryl substituted pyrazoline whose delta-position contains ester group and its liquid phase synthesis method is presented, which can be developed into medicine, pesticide and light sensitive material.
Abstract: The present invention discloses a kind of 1,3-aryl substituted pyrazoline whose delta-position contains ester group and its liquid phase synthesis method. In the organic solvent, in the presence of alkali the substituted acryloyl chlorine is coupled on the soluble resin, under the action of organic alkali the isoequivalent aromatic aldehyde and aromatic hydrazine hydrochloride are mixed to obtain the correspondent hydrazone, then the substituted acrylic ester loaded by soluble resin and oxidant are added, and the above-mentioned materials are undergone the ring-forming reaction of one-pot method so as to obtain the 1,3-aryl substituted pyrazoline whose delta-position contains ester group which is loaded on the resin. In the alcohol solvent and under the catalysis of correspondent alcohol sodium the pyrazoline can be separated from soluble resin so as to obtain the invented product with high yield rate and high purity. It can be developed into medicine, pesticide and light sensitive material.
Patent•
22 Nov 2003TL;DR: In this paper, the substituted pyrazoline carboxanilides of formula (I) are defined as follows: R1, R2, R3 and R4 are as defined in the description.
Abstract: The invention relates to the novel substituted pyrazoline carboxanilides of formula (I), wherein R1, R2, R3 and R4 are as defined in the description. The invention also relates to several methods for producing these substances and to their use in pest control.
Patent•
18 Jul 2003
TL;DR: In this article, a photoresist polymer comprising a pyrazoline-based monomer having azide group is represented by formula 5, where each of R' and M is the same as the above formula 1, x, y and z are a molar ratio of each monomer, each of x and y is 0.7-0.99, and n is a polymerization degree of each polymer.
Abstract: PURPOSE: Provided are a photoresist polymer comprising a pyrazoline-based monomer having azide group, which is an eco-friendly, and has excellent storage stability and shows high resolution and sensitivity, and a photoresist composition. CONSTITUTION: The pyrazoline-based monomer is represented by formula 1. In the formula 1, R is CHO, COOH or (CH3)2OCH(CH2)m, m is 0, 1, or 2, R' is CH3 or C6H5, M is H or an element capable of converting into cation in aqueous solution. The photoresist polymer comprising the pyrazoline-based monomer is represented by formula 5. In the formula 5, each of R' and M is the same as the above formula 1, x, y and z are a molar ratio of each monomer, each of x and y is 0.7-0.99, z is 0.01-0.3, m is 0, 1 or 2, and n is a polymerization degree of each polymer and has a value of 2 or more.