Pyrazoline Research Articles

Plastic Scintillators and Radiation Detectors Based on Triphenyl Pyrazoline Derivatives

AbstractPlastic scintillators (PS) allow design of portative lightweight devices for quantification of low‐activity radiation sources. We have recently suggested a new type of organic fluorophores based on triphenyl pyrazoline (PZ) derivatives with high fluorescence quantum yield showing high radioluminescence when combined with a polyvinyltoluene (PVT) matrix. In this publication we report on radioluminescence properties of the PZ−X family with various halogen substitution (X=F, Cl, Br, I), or having vinyl functional group (vPZ, X=vinyl). PS based on such fluorophores and PVT matrix can be prepared as bulk samples, micrometer size beads or cladding on optical fibers. Application of fluorophores with vinyl functional groups enabled their enhanced interaction with the matrix due to covalent bonding between the components. We demonstrate high performance of PZ−X fluorophores and especially vPZ fluorophore in fabrication of nanocomposites for detection of various types of radiation. Scintillators have enhanced gamma ray detection capabilities with an addition of triphenyl Bi, or Gd2O3 nanoparticles. High fluorescence quantum yield and luminosity of PZ fluorophores allows dramatical reduction of their content in PS systems. Mechanisms of energy transfer and conversion during scintillation process are discussed. Special consideration is given to enhancement of α/β and neutron/gamma (n/γ) pulse shape discrimination (PSD) function of the developed scintillators.

Highly functionalized pyrazolines from symmetric and asymmetric 1,2-disulfonylhydrazines: a combination of experimental and DFT perspectives

Highly functionalized pyrazolines from symmetric and asymmetric 1,2-disulfonylhydrazines: a combination of experimental and DFT perspectives

Copper-Catalyzed Sulfeno-/Seleno-amination of β,γ-Unsaturated Hydrazones with Disulfides/Diselenides toward Sulfenylated/Selenylated Pyrazolines

Copper-Catalyzed Sulfeno-/Seleno-amination of <i>β,γ</i>-Unsaturated Hydrazones with Disulfides/Diselenides toward Sulfenylated/Selenylated Pyrazolines

Synthesis of New Pyrazoline Derivatives and Its Antimicrobial and Antioxidant Activities

Resistance gained by microorganism to conventional antimicrobial agents has lead to the development of new antimicrobial agents against pathogenic microbes. Chalcones and their derivatives proved to be an important molecular scaffold for the search of new pharmaceutically active molecules. Among the various derivatives of chalcones, synthesis of pyrazolines has gained major attention due to their promising biological activities such as anticancer, antimicrobial, antidepressant, immunosuppressive, anti-inflammatory, etc.1−8 Many studies revealed that incorporation of pyrazole moiety into various heterocyclic ring systems gives worthwhile molecules from the biological point of view.9−11 Several marketed drugs such ascelecoxib12 and rimonabant13 contains pyrazole as their core molecular unit.14,15

Fine-tuning of blue-emitting pyrazoline using phenyl and thiophene terminal group substituents

Two pyrazoline (PYR) materials with phenyl and thiophene terminal group substituents (PPYR and TPYR, respectively) were synthesized, and their optical properties were examined. Variation of the terminal group allowed manipulation of the physicochemical properties of PYR based on differences in the intracharge transfer of the molecules. The peak maxima of the absorption/emission spectra PPYR and TPYR differed, occurring at 348/439 and 366/446 nm, respectively. The difference in the optical properties was due to greater electron transfer of the thiophene group compared with the phenyl group, which led to an increase in the intracharge transfer of the thiophene-containing molecule. These results demonstrate that the physicochemical properties of PYR materials can be tuned by modification with suitable substituents.

A Review on the Synthesis and Chemistry of Bioactive Pyrazolines Bearing 1,2,4-Triazine Moieties

A Review on the Synthesis and Chemistry of Bioactive Pyrazolines Bearing 1,2,4-Triazine Moieties

STUDIES ON SYNTHESIS, REACTIONS AND AND ANTIMICROBIAL ACTIVITIES OF 3-ALKYL-5-DIALKYLAMINOMETHYL PYRAZOLINES

By the reaction of 1-alkyl-4-dialkylamino-but-2-en-1-ones with hydrazine hydrate there have been synthesized 3-alkyl-5-dialkylaminomethyl pyrazolines, which with chloranhydride of acetic and chloroacetic acids have been converted into 3-alkyl-1-acetyl and 3-alkyl-5-(dialkylaminomethyl)-1-(2-chloromethylcarbonyl) pyrazolines. By interaction of 3-alkyl-5-dialkylaminomethyl)-1-(2-chloromethylcarbonyl) pyrazolines with potassium phenolates there have been synthesized 3-alkyl-5-(dialkylaminomethyl)-1-(2-phenoxyacetyl)pyrazolines. 3-alkyl-5-dialkylaminomethyl pyrazolines and their 1-substituted derivatives show the expressed antimicrobial activities.

Synthesis of Some Pyridazine Based Pyrazolines

Synthesis of Some Pyridazine Based Pyrazolines

Photoinduced Bioorthogonal 1,3-Dipolar Poly-cycloaddition Promoted by Oxyanionic Substrates for Spatiotemporal Operation of Molecular Glues.

PGlue(PZ), a pyrazoline (PZ)-based fluorescent adhesive which can be generated spatiotemporally in living systems, was developed. Since PGlue(PZ) carries many guanidinium ion (Gu(+)) pendants, it strongly adheres to various oxyanionic substrates through a multivalent salt-bridge interaction. PGlue(PZ) is given by bioorthogonal photopolymerization of a Gu(+)-appended monomer (Glue(TZ)), bearing tetrazole (TZ) and olefinic termini. Upon exposure to UV light, Glue(TZ) transforms into a nitrileimine (NI) intermediate (Glue(NI)), which is eligible for 1,3-dipolar polycycloaddition. However, Glue(NI) in aqueous media can concomitantly be deactivated into Glue(WA) by the addition of water, and the polymerization hardly occurs unless Glue(NI) is concentrated. We found that, even under high dilution, Glue(NI) is concentrated on oxyanionic substrates to a sufficient level for the polymerization, so that their surfaces can be point-specifically functionalized with PGlue(PZ) by the use of a focused beam of UV light.

Photoinduced Bioorthogonal 1,3‐Dipolar Poly‐cycloaddition Promoted by Oxyanionic Substrates for Spatiotemporal Operation of Molecular Glues

AbstractPGluePZ, a pyrazoline (PZ)‐based fluorescent adhesive which can be generated spatiotemporally in living systems, was developed. Since PGluePZ carries many guanidinium ion (Gu+) pendants, it strongly adheres to various oxyanionic substrates through a multivalent salt‐bridge interaction. PGluePZ is given by bioorthogonal photopolymerization of a Gu+‐appended monomer (GlueTZ), bearing tetrazole (TZ) and olefinic termini. Upon exposure to UV light, GlueTZ transforms into a nitrileimine (NI) intermediate (GlueNI), which is eligible for 1,3‐dipolar polycycloaddition. However, GlueNI in aqueous media can concomitantly be deactivated into GlueWA by the addition of water, and the polymerization hardly occurs unless GlueNI is concentrated. We found that, even under high dilution, GlueNI is concentrated on oxyanionic substrates to a sufficient level for the polymerization, so that their surfaces can be point‐specifically functionalized with PGluePZ by the use of a focused beam of UV light.

Synthesis and anticonvulsant activity of certain chalcone based pyrazoline compounds

Convulsions are involuntary, violent, spasmodic and prolonged contractions of skeletal muscles. That means a patient may have epilepsy without convulsions and vice versa. Epilepsy is a common neurological abnormality affecting about 1% of the world population. The primary objectives of these synthesized compounds are to suppress seizures and provide neuroprotection by minimizing the effects from seizure attacks. Here some of the chalcones and chalcone based various pyrazolines were evaluated for anticonvulsant activity. Their structures have been elucidated on the basis of elemental analyses and spectroscopic studies (IR, 1H-NMR & Mass spectroscopy). A preliminary evaluation of the prepared compounds has indicated that some of them exhibit moderate to significant anticonvulsant activity compared to a diazepam standard1-3. All compounds were tested for their anticonvulsant activity using maximal electroshock induced convulsions (MES) in mice at a dose level of 4 mg/kg.b.w. The compounds Ph1, Ph2 , Py2 ,Py3 and Py4 have shown to good anticonvulsant activity when doses are administered as 25mg/ kg.b.w , reduced the phases of seizures severity and found to be active and also increased survival rate. Remaining compounds are less efficacious.

Synthesis, Characterization and Antimicrobial Activity of Some New Pyrazoline Derivatives of 3-Aryl-2-Isobutanoyl-N-Phenyl-Acrylamide

Synthesis, Characterization and Antimicrobial Activity of Some New Pyrazoline Derivatives of 3-Aryl-2-Isobutanoyl-N-Phenyl-Acrylamide

Synthesis and Phototoxic Activity of Isoxazole and Pyrazoline Derivatives Containingα-Terthiophene

α-三联噻吩（a-T）是一类具有优异性能的光活化农药．以三联噻吩为先导化合物，经a醛基化制得关键中间体2-醛基三联噻吩，然后与取代苯乙酮反应，得到三联噻吩取代的α,β-不饱和酮，再与盐酸羟胺、水合肼关环，最终合成两类含3，5-二芳基异嗯唑和3，5-芳基吡唑啉的α-三联噻吩衍生物．其结构经1HNMR，IR和元素分析确证．初步生物活性测定试验表明，绝大多数目标化合物具有良好的光活化活性，异嗯唑类衍生物的光活化活性普遍要好于吡唑啉类衍生物，其中化合物3b光照前后的细胞毒杀活性差异为64．06倍．但部分吡唑啉类衍生物整体显示出较高的细胞毒杀活性，其中化合物4d光照细胞毒杀活性为83．9％．

Potent anti-inflammatory and analgesic activities of new derivatives of chalcone, pyridine, pyrazole, and isoxazole incorporated into 5,6,7,8-tetrahydronaphthalene

Objective Synthesis of new series of 5,6,7,8-tetrahydronaphthalene derivatives conjugated with chalcone, pyridine, pyrazole and isoxazole functionalities hoping to circumvent the unwanted ulcerogenic and other side effects of the already used nonsteroidal anti-inflammatory drugs. Background Most currently used nonsteroidal anti-inflammatory drugs (NSAIDs) suffer from limitation in their therapeutic uses, since they cause gastrointestinal and renal side effects related to inhibition of cyclooxygenase1 (Cox1) in tissues where prostaglandins exert physiological effects. Methodology Reaction of 2-acetyl tetralin (1) with some aromatic aldehydes in the presence of malononitrile yielded 2-amino-3-cyanopyridine derivatives 2a–c. Condensation of compound 1 with aromatic aldehydes afforded the chalcone derivatives 3a–c. Then, compound 3a reacted with hydrazine hydrate or phenyl hydrazine and yielded pyrazoline derivatives 4 or 5, respectively. Also, the reaction of compound 3c with hydroxylamine hydrochloride afforded the isoxazole derivative 6. Anti-inflammatory properties of the synthesized compounds were evaluated in vivo utilizing formalin induced paw edema method in rats, analgesic activities were tested via both hot plate and writhing methods. Results Derivatives 2c and 3c revealed promising results when the anti-inflammatory, analgesic, and ulcerogenic activities of the synthesized compounds were evaluated. All of the compounds induced significant central and peripheral analgesia. The derivatives 2a, 2c, 3a, 3b, 3c, 5, and 6 showed higher activity than the standard ibuprofen.

ChemInform Abstract: Unexpected Rearrangements of Bicyclic Pyrazolines Derived from 6,6-Diphenylpentafulvene.

ChemInform Abstract: Unexpected Rearrangements of Bicyclic Pyrazolines Derived from 6,6-Diphenylpentafulvene.

Recyclization of 5-hydroxy-2-pyrazolines in the reaction with N-nucleophiles

The reactions of 5-hydroxy-1-tosyl-2-pyrazolines with amines or with hydrazine have been investigated. We have shown that these compounds are convenient substrates for the synthesis of 5-aminosubstituted pyrazolines and NH-pyrazoles.

Synthesis of 1'-arylcarbamoylthiocarbonyl-3'-methyl-3-oxo-androst-4-eno[16α,17α-d]pyrazolines

Synthesis of 1'-arylcarbamoylthiocarbonyl-3'-methyl-3-oxo-androst-4-eno[16α,17α-d]pyrazolines

Cycloaddition of Bis‐1,3‐dipolar Reagents to 1,3‐Diarylprop‐2‐en‐1‐ones.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Cycloaddition of bis‐1,3‐dipolar reagents to 1,3‐diarylprop‐2‐en‐1‐ones

AbstractBis pyrazolines and isoxazolines were prepared by 1,3‐dipolar cycloaddition of benzene‐1,3/1,4‐dicarboxaldehyde dihydrazones and dioximes to 1,3‐diaryl‐prop‐2‐en‐1‐ones. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:379–383, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10169

Localized-state distributions in molecularly doped polymers determined from time-of-flight transient photocurrent

Localized-state distributions have been studied in a molecularly doped polymer (MDP) system of a polymer binder (polycarbonate) doped with charge-transporting [N, N′-diphenyl-N, N′-bis(3-methylphenyl)(1,1′-biphenyl)-4,4′-diamine (TPD)] and trap-forming molecules [1-phenyl-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline (PRA)] simultaneously by means of the conventional time-of-flight (TOF) transient photocurrent measurements. The existence of a transport energy in the MDP system is experimentally shown by comparing Gaussian distributions of localized states deduced by the Gaussian disorder model, due to Bässler and co-workers [H. Bässler, Phys. Status Solidi B 175, 15 (1993)], with localized-state distributions determined from the analysis of the TOF transient photocurrent data, based on the trap-controlled band transport [H. Naito, J. Ding, and M. Okuda, Appl. Phys. Lett. 64, 1830 (1994)]. The transport energy is found to be located at the center of the Gaussian distribution due to the host TPD molecules. It is also found that at 0.1 mol % PRA addition, the Gaussian distribution of localized states due to TPD molecules is broadened through the random electrostatic potential generated by dipoles of PRA, and at 1 mol % PRA addition, the localized-state structure due to PRA molecules, as well as the further broadening of the Gaussian distribution, are observed. The energy level of the structure is determined to be 0.54 eV above the transport energy, which is almost equal to the difference in the ionization potential between PRA and TPD.