Novel four-hydrogen-bond assembled oligoamide dimer with pyrazoline moieties and its photoluminescent properties

In this paper, the synthesis and characterization of a triarylpyrazoline modified four-H-bonded molecular duplex are described. Its molecular structure has been confirmed by ^1H NMR and ESI-MS. The duplex emits strong pure blue light peaking at 448 and 452 nm under UV photoexcitation in solution and solid state, respectively, and its relative photoluminescence quantum efficiency in solution is determined as 0.778 using quinine sulfate as reference. In concentration of 〉40 mmol/L, the duplex can gelate DMSO, and the organogel formed shows good pure blue photoluminescence too. This novel duplex, for its well-defined structure and efficient photoluminescence property, is a prospective candidate for pure blue electroluminescent emitter.

Novel fluorene-carzazole-based conjugated copolymers containing pyrazoline and benzothiazole segments for blue light-emitting materials

A series of novel fluorene-carbazole-based copolymers with pyrazoline and benzothiazole units were synthesized successfully through Suzuki coupling reactions. The molecular structures and thermal properties of these polymers were characterized by FTrIR, 1H NMR, DSC and TGA. GPC results indicated that the weight-average molecular weight （Mw） and polydispersity of these polymers were in range （12,0（0）-14,000） and （1.8-2.0）, respectively. The two resulting polymers have high photoluminescence quantum efficiency implying that they may be promising candidates for polymer light-emitting diodes （PLEDs）.

Syntheses and Crystal Structures of Pyrazoline Derivants

Two pyrazoline derivants 1-(2-benzothiazole)-3-phenyl-5-(3-thiophene)-2- pyrazoline (BPTP) and 1-(2-benzothiazole)-3-(2-thiophene)-5-phenyl-2-pyrazoline (BTPP) have been synthe- sized and their crystal structures were determined by X-ray single-crystal diffraction. Crystal of BPTP belongs to triclinic, space group P1 with a = 9.4430(11), b = 9.9384(13), c = 9.9394(13) ?, α = 83.107(10), β = 79.947(10), γ = 70.221(7)o, V = 862.42(19) ?3, Z = 2, Dc = 1.392 g/cm3, μ(MoKα) = 0.316 mm-1, F(000) = 376, λ = 0.71070 ?, (?ρ)max = 0.348, (?ρ)min = –0.481 e/?3, the final R = 0.0407 and wR = 0.1055 for 2844 observed reflections with I > 2σ(I). Crystal of BTPP is of monoclinic, space group P21/c with a = 11.6158(17), b = 11.2796(18), c = 13.082(2) ?, α = 90, β = 91.087(4), γ = 90o, V = 1713.7(5) ?3, Z = 4, Dc = 1.401 g/cm3, μ(MoKα) = 0.318 mm-1, Mr = 361.07, F(000) = 752, λ = 0.71070 ?, (?ρ)max = 0.322, (?ρ)min = –0.330 e/?3, the final R = 0.0563 and wR = 0.1058 for 3434 observed reflections with I > 2σ(I).

Preparation and Properties of Rare Earth Complexes with 5-Phenyl Pyrazoline Dithioformate

Nine complexes of rare earths with 5 phenyl pyrazoline dithioformate, Na[RE(S 2CNC 9H 9 N) 4· x H 2O (RE=La～Dy, Y, except for Ce and Pm) were synthesized in dry N 2 atmosphere and characterized by elemental analyses, molar conductance, IR spectra, thermal analyses. The results show that the ligands coordinate to the RE ion through two sulphur atom donors. Thermal analyses indicate that the thermal stability of the complex is not higher than that of sodium 5 phenyl pyrazoline dithioformate. The complexes are easily soluble in acetonitrile and tetrahydrofuran. The molar conductance values of the complexes measured in acetonitrile (1 24～1 32×10 -3 mol·dm -3 ) at 25 ℃ are in the range of 86～104 Ω -1 ·cm 2·mol -1 , indicating that they are 1∶1 electrolytes.

TD-DFT Study on Pyrazoline Derivatives

The molecular structures of ground state and first single excited state for pyrazoline derivatives are optimized with DFT B3LYP method and ab initio “configuration interaction with single excitations”（CIS） method, respectively. The frontier molecular orbital characteristics have been analyzed systematically, and the electronic transition mechanism has been discussed. Electronic spectra are calculated by using TD-DFT method. These results are consistent with those from the experiment.

TBPA^(+·) mediated aromatization of 1,3,5-trisubstituted pyrazolines

1,3,5-Trisubstituted pyrazolines were oxidized to the corresponding pyrazoles in high yield with tris（4-bromophenyl）aminium （TBPA＊＊） hexachloroantimonate in chloroform at room temperature.

Synthesis of Pyrazolines Used as Blue Organic Electroluminescence Materials

Three kinds of pyrazolines were designed and synthesized. Their structures were elucidated by IR, (HNMR)-H-1, MS, UV and elemental analysis. Their luminescent properties were determined, which indicated that they had strong blue fluorescent properties. One of them was designed to have good film formation. All the three kinds of pyrazolines can be used as blue organic electroluminescence materials (OELMs).

Synthesis and Spectral Characterization of Novel 2-Pyrazoline and Bis-2-Pyrazoline Containing Quinoline Moiety

Eight new compounds containing in their structures substituted quinoline and pyrazole entity were synthesized in good to excellent yield by cyclocondensation reaction of chalcones and hydrazine hydrate. This reaction was conducted in formic acid in presence of BF3·Et2O or in acetic acid. These approaches were extended to bis-chalcones, which delivered functionalized bispyrazolines. The structures of the prepared compounds were confirmed by IR, 1HNMR, 13CNMR and mass spectral analysis.

Design, Synthesis and Biological Evaluation of Novel Antitubercular Agents by Combining Pyrazoline and Benzoxazole Pharmacophores

Various recent reports on Tuberculosis have alarmed an increase in the patient class and subsequent death rates across the globe. Over and above the spread of more dangerous and fatal forms of tuberculosis like MDR-TB i.e. multiple-drug resistance tuberculosis, XDR-TB i.e. extensively-drug resistance tuberculosis & TDR-TB i.e. total-drug resistance tuberculosis has forwarded an urgent need to discover novel antitubercular agents. The current work is aimed at combining two previously well-known pharmacophores (pyrazoline and benzoxazole nucleus) in order to design and synthesize a series of novel benzoxazole-based pyrazoline derivatives. The synthesized target compounds were structurally confirmed by LCMS, 1H-NMR and 13C-NMR analysis. The target compounds were In vitro evaluated against M. tuberculosis H37Rv strain, multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) strains. The In vitro screening results depicted that majority of the target compounds displayed potent activity with MIC in a range of ~0.8 to 6.25 μg/mL. Many compounds were found to be more potent than isoniazid against MDR-TB with MIC value 3.12 μg/mL and XDR-TB with MIC value 12.5 μg/mL. Cytotoxicity assay of these active compounds on VERO cell lines also displayed good selectivity index.

A Novel Pyrazoline-based Starburst Amorphous Molecular Material

A pyrazoline-containing starburst molecule, 4,4’,4"-tris[(1,3-diphenyl-4,5-dihydro-1H- pyrazol)-5-yl]-triphenylamine (Tris-5-DPP), was synthesized in a facile way, which can form amorphous thin films with glass transition temperature as high as 136 °C.

TCCA/NCS-Promoted Cascade Cyclization of <i>β</i>, <i>γ</i>-Unsaturated Compounds: Synthesis of Isoxazolines and Pyrazolines

2-Isoxazolines and 2-pyrazolines have been derived from oxime and hydrazone derivatives reacted with N-chlorosuccinimide (NCS) and trichloroisocyanuric acid (TCCA). Cyclization strategy is developed for the reaction of β, γ-unsaturated hydrazones with the TCCA to drive 2-pyrazolines and the reaction of β, γ-unsaturated oximes with NCS to derive 2-isoxalzolines. Structures of all new 2-isoxazolines and 2-pyrazolines have been elucidated by microanalyses, 1H, 13C NMR and Mass spectroscopies.

Formation of 3-Arylpyrazolines and 1-Aroylethyl-3-arylpyrazolines via 3-Aroylethylsydnone with HCl in Ethyl Acetate

Treatment of 3-aroylethylsydnone 1 with HCl leads to 3-arylpyrazoline 2 or 1-aroylethyl-3-arylpyrazoline 3 under different conditions.

Cytoprotective effects of amifostine,ascorbic acid and N-acetylcysteine against methotrexate-induced hepatotoxicity in rats

AIM: To investigate the potential role of oxidative stress and the possible therapeutic effects of N-acetyl cysteine (NAC), amifostine (AMF) and ascorbic acid (ASC) in methotrexate (MTX)-induced hepatotoxicity.

Simultaneous Determination of N-Acetyl Cysteine and Taurine by HPTLC Method in Active Pharmaceutical Ingredient and Pharmaceutical Dosage Form

Specific, precise and sensitive TLC-Densitometric method was developed and validated for the simultaneous estimation of N-Acetyl cysteine and Taurine in active pharmaceutical ingredient and pharmaceutical dosage form. An effective separation was achieved on pre-coated silica gel HPTLC plates by using n-butanol:acetic acid:water (8:0.5:1.5 v/v/v). The spots were scanned densitometrically at 295 nm. The RF values of N-Acetyl cysteine and Taurine were found to be 0.29 and 0.52, respectively. Calibration curves were linear in the range of 30 - 180 and 100 - 600 ng/band for N-Acetyl cysteine and Taurine, correspondingly with correlation coefficients of 0.999. The developed method was validated as per ICH guidelines. The limits of detection were 11.24 and 63.40 ng/spot for NAC and TAU respectively. The method developed was found to be precise and specific for the simultaneous analysis of N-Acetyl cysteine and Taurine in pure and tablet dosage form.

Reversal Effects of N-Acetyl Cysteine on <i>Moringa oleifera</i>Leaves-Induced Sub-Acute Hepatotoxicity in Wistar Albino Rats

Background: M. oleifera is a highly valued medicinal plant used widely from time immemorial to treat various ailments. However, with continued un-standardized use of the plant leaves, studies have reported organ toxicity to the liver, kidney and the heart. As communities continue to use M. oleifera leaves for its medicinal and nutritional values, there is need to find an antidote for its hepatotoxicity. Aim: The study established the reversal effect of N-Acetyl Cysteine (NAC) on M. oleifera aqueous leaf extract-induced hepatotoxicity in Wistar albino rats. Methods: Twenty-four (24) rats received a toxic dose (8.05 g/kg bwt) of M. oleifera leaf extract for 28 days to cause sub-acute hepatotoxicity. They were divided into 4 groups of 6 rats each. Group I received 1 ml normal (control group), Group II received 1000 ng/kg NAC, Group III received 1200 mg/kg NAC and Group IV received 1500 mg/kg NAC. Another group of 6 rats (Group V) received 0.75 mg/kg Paracetamol to cause hepatotoxicity. Group V (a positive control) received the prescribed clinical dose of 1200 mg/kg NAC which reverses the hepatotoxicity. All the NAC doses were given once a day intragastric for 7 days. On days: 1, 3 and 7 of receiving NAC, liver serum enzymes and bilirubin were measured. On day 7 the animals were sacrificed and liver tissue harvested for histopathology analysis. Results: A dose of 8.05 g/kg of M. oleifera leaf extract and 0.75 mg/kg Paracetamol were able to induce hepatotoxicity in Wister albino rats in 28 days. The M. oleifera extract induced hepatotoxic rats treated with NAC at doses of 1000 mg/kg, 1200 mg/kg and 1500 mg/kg, had a reduction in mean serum liver enzymes, plus reduced mean serum bilirubin levels. The liver histopathological analysis showed reduced inflammation after treatment with NAC for 3 and 7 days in the M. oleifera and paracetamol induced hepatotoxic rats. Conclusion: NAC can reverse M. oleifera leaf aqueous extract-induced sub-acute hepatotoxicity in Wistar Albino rats.

Therapeutic potential of N-acetyl cysteine during COVID-19 epoch

N-acetyl cysteine(NAC)is a promising drug for prophylaxis and treatment of coronavirus disease 2019(COVID-19)based on antioxidant and anti-inflammatory mechanisms.Further studies with cautious approach are needed to establish the benefits and risks before considering NAC as an adjuvant treatment for COVID-19.

Repurposing the antioxidant and anti-inflammatory agent N-acetyl cysteine for treating COVID-19

Although several considerations have been raised suggesting a beneficial effect of N-acetyl cysteine(NAC)for the treatment of severe acute respiratory syndrome coronavirus 2 infection,there is currently no clinical evidence that NAC truly prevents coronavirus disease 2019(COVID-19),reduces the severity of the disease,or improves the outcome.Appropriately designed clinical trials are warranted to prove or disprove a therapeutic effect of NAC for COVID-19 patients.

三氟甲磺酸催化制备环丙烷结构燃料中间体吡唑啉

通过实验对腙分子内成环制备环丙烷结构高能燃料中间体吡唑啉的酸催化剂进行了筛选,其中三氟甲磺酸的酸性最强,以其来催化合成3,5,5-三甲基-2-吡唑啉,转化率98%,选择性>99%。吡唑啉高温脱氮制备对应环丙烷结构产物,转化率>95%。此外,基于密度泛函理论B3LYP/6-311G(d,p)水平,计算了酸催化腙成环反应机理与位点,表明酸催化可以有效降低反应活化能,促进成环反应。Mulliken电荷分布分析显示,腙的质子化是该反应的关键起始步骤。上述结果表明强酸催化剂有利于加快腙转化为吡唑啉的反应速率,且腙的空间位阻是反应关键因素,空间位阻较小的底物转化率较高。该研究为吡唑啉的合成与环丙烷结构燃料的制备提供了一种可行的方法。