The reaction rate of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one (MCI-186)) with hydroxyl radical

The pyrazoline derivative edaravone is a potent hydroxyl radical scavenger that has been approved for attenuation of brain damage caused by ischemia-reperfusion. In the present work, we first determined the rate constant, k(r), at which edaravone scavenges radicals generated by a Fenton reaction in aqueous solution in the presence of the spin trap agent, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), which competed with edaravone. We detected the edaravone radicals in the process of hydroxyl radical scavenging and found that edaravone reacts with hydroxyl radical around the diffusion limit (k(r)=3.0 x 10(10) M(-1) s(-1)). The EPR (electron paramagnetic resonance) spectrum of the edaravone radical was observed by oxidation with a horseradish peroxidase-hydrogen peroxide system using the fast-flow method. This radical species is unstable and changed to another radical species with time. In addition, it was found that edaravone consumed molecular oxygen when it was oxidized by horseradish peroxidase (HRP)-H(2)O(2) system, and that edaravone was capable of providing two electrons to the electrophiles. The possible mechanisms for oxidation of edaravone were investigated from these findings.     

Spirobutyrolactone derived from 1-phenyl-3-methyl-2-pyrazolin-5-one

X-ray diffraction and NMR spectral examination have shown that 1-phenyl-3-methyl-2-pyrazolin-5-one reacts with methyl acrylate in methanol to give spiro[(1-phenyl-3-methyl-2-pyrazolin-5-one)-4,5-butyrolactone]. The conformation has been shown to be the same in the crystal and in solution, the pyrazoline ring has been found to be nonplanar, the reasons for the acoplanarity established, stabilizing and destabilizing interactions studied, and the orientation of the phenyl substituent relative to the pyrazolin-5-one ring determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 909–913, July, 1988.     

O-Alkylation of 3-hydroxy-1-phenyl-2-pyrazolin-5-one

3-Hydroxy-1-phenyl-2-pyrazolin-5-one 1 reacts with primary, secondary and allylic alcohols under catalytic acidic conditions and in the presence of 3 Å molecular sieves, to afford 3-alkoxy-1-phenyl-2-pyrazolin-5-ones 3 .     

Alkyldithiocarboxylation of 3-hydroxy-1-phenyl-2-pyrazolin-5-one

4-Alkyldithiocarboxylate-3,5-dihydroxy-1-phenylpyrazoles 2, are prepared in good yield by the reaction of 3-hydroxy-1-phenyl-2-pyrazolin-5-one 1 with sodium acetate in dimethylformamide (DMF), carbon disulfide and alkyl halides.     

Effect of crown ethers on the solvent extraction and separation of lanthanide(III) ions with 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one

Synergistic solvent extraction of 14 lanthanides with mixtures of 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one (HP) and the crown ethers (S), 18-crown-6, benzo-18-crown-6 or dibenzo-18-crown-6 from an aqueous chloride medium with the constant ionic strength of 0.1 mol dm⁻³ was investigated using benzene as a diluent. The composition of the species extracted was determined as LnP3 · S. The addition of a crown ether to the chelating extractant produced rather significant synergistic effects. On basis of experimental data, values of equilibrium constants, synergistic coefficients, and separation factors were calculated.     

Preparation of 3(5)-phenyl-1-hydroxypyrazole 2-oxide and 4-methyl-3(5)-phenyl-1-hydroxypyrazole 2-oxide

Nitrosation of acrylophenone oxime or of methacrylophenone oxime with n-butyl nitrite in the presence of pyridine and copper(II) sulfate gives the copper complexes of the title compounds. The free 1-hydroxypyrazole 2 -oxides are isolated by treating the copper complexes with dilute sodium hydroxide, filtration, and acidification of the basic filtrates. The title compounds are the first examples of 1-hydroxypyrazole 2 -oxides in which the C3(5) ring position is unsubstituted.     

Formation and structure of 1-Amino-4-methyl-4-(4-methyl-5-phenyl-1H-pyrazol-3-ylamino)-3-phenyl-4,5-dihydro-1H-pyrazol-5-one

The title compound 3 was obtained during the rearrangement of isoxazol-5-yl hydrazine 1 to 1-aminopyrazolone 2 at 115°. X-ray analysis of the corresponding benzylidene derivative allowed us to achieve the structure assignment.     

Potentiometric and thermodynamic studies of 3-methyl-1-phenyl-{p-[N-(pyrimidin-2-yl)-sulfamoyl]phenylazo}-2-pyrazolin-5-one and its metal complexes

The dissociation constants of 3-methyl-1-phenyl-{p-[N-(pyrimidin-2-yl)sulfamoyl]phenylazo}-2-pyrazolin-5-one and metal-ligand stability constants of its complexes with some transition metal ions have been determined potentiometrically in 0.1 M-KCl and ethanol—water mixture (30 vol. %). The order of the stability constants of the formed complexes increases in the sequence Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, La³⁺, Hf³⁺, UO ₂ ²⁺ , Zr⁴⁺. The effect of temperature was studied and the corresponding thermodynamic parameters (ΔG, ΔH, and ΔS) were derived and discussed. The dissociation process is nonspontaneous, endothermic, and entropically unfavourable. The formation of the metal complexes was found to be spontaneous, exothermic, and entropically favourable. Abstracted from his M.Sc. Thesis.     

Pulse radiolysis study on the free radical scavenging activities of puerarin

Free radical theory of biology and medicine suggests that free radicals are involved in the happening of many chronic diseases including cancers and cardiovascular diseases, and natural antioxidants play positive effect in the prevention of such diseases[1]. This theory leads to much interest in the free radical scavenging activities of the pharmacologically active components in herbal medicines. Puerarin (fig. 1), a compound of isoflavone, is isolated from Chinese herbal medicine radix puera…     

The synthesis and structural studies of mixed ligand complex,tris(1-phenyl-3-methyl-4-trifluoroacetyl-pyrazol-5-one)mono(1-phenyl-3-methyl-pyrazol-5-one)neodymium(III) monohydrate

A mixed ligand neodymium complex containing 1-phenyl-3-methyl-4-trifluoroacetyl-pyrazol-5-one (HPMTFP) and 1-phenyl-3-methyl-pyrazol-5-one (PMP), with molecular formula Nd (PMTFP)₃·PMP·H₂O was synthesized. Its crystal and molecular structure has been determined by single crystal X-ray diffraction method. The complex crystallizes in monoclinic system with space group C⁵₂-P2₁/n. There are four formula units in a cell of dimensions a = 12.837(3), b = 23.763(5), c = 16.810(4) Å, β = 109.58(2)°. The structure has been refined by full-matrix least-squares techniques to a final R value of 0.0487 and R_w value of 0.432. The neodymium atom is coordinated to eight oxygen atoms with the average Nd—O bond length 2.439Å. Its thermostability, and mass spectrum have been discussed.     

4-双(1-苯基-3-甲基-4-吡唑啉-5-酮)甲烷的晶体结构

杂环化合物1 苯基 3 甲基 4 吡唑啉 5 酮(ＨＰＭＰ)为β 二酮,不仅可用作金属离子的萃取剂,还可用于核磁共振的位移试剂,也可用于激光、催化、生化、医学等领域[1-4]。我们从ＰＭＰ出发,合成了它的Ｃｏ(Ⅱ),Ｎｉ(Ⅱ),Ｃｕ(Ⅱ)和Ｚｎ(Ⅱ)的络合物[5,6]。利用单晶Ｘ 射线衍射分析方法报道了标题化合物的晶体结构。1　实验部分在合成ＰＭＰ席夫碱化合物的过程中,得到标题化合物的单晶体。元素分析结果(括号内为计算值)Ｃ%:69 87(69 98),Ｈ%:5 62(5 59),Ｎ:15 61(15 55)。红外光谱(ＫＢｒ):1645和1637ｃｍ-1的强吸收峰归属为羰基的伸缩振动,…     

Coordination compounds of dysprosium(III) with 3-methyl-1-phenyl-4-formylpyrazol-5-one diacyldihydrazones

Coordination compounds of dysprosium(III) with diacyldihydrazones of saturated dicarboxylic acids, imino-, oxo-, and thiodiacetic acids, and 3-methyl-1-phenyl-4-formylpyrazol-5-one (H₄L) are described. [Dy₂(H₂L^O)₃] · 7.5CH₃OH · 3H₂O was subjected to X-ray diffraction analysis: space group \(R\bar 3\) , a = 17.349(1) Å, c = 65.669(4) Å, Z = 6, R = 0.076, R _w = 0.243 (5301 reflections with I ≥ 2σ(I)). The complex is established to have a binuclear structure and contain dysprosium ions linked via three bridging ligands. The coordination polyhedron of the Dy atom had a three-capped trigonal prism geometry. The magnetic properties of the synthesized complexes were studied.     

Complexes of Zr(IV) and Nb(V) with 1-phenyl-3-methyl-4-benzoyl-pyrazole-5-one

The complexing of Zr(IV) and Nb(V) by 1-phenyl-3-methyl-4-benzoyl-pyrazole-5-one (HPMBzP) in various mineral acids has been studied by solvent extraction. The pyrazolone tautomers have been isolated and characterised, and the composition and structure of zirconium and niobium complexes have been established using various chemical and spectroscopic techniques.     

Physicochemical properties of novel mixed-ligand complexes of zirconium and hafnium bis(4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-onato)phthalocyaninates

We have studied the spectral (IR, PMR, electronic absorption spectra) and luminescent properties of novel mixed-ligand complexes of zirconium(IV) and hafnium(IV) phthalocyaninates with 4-benzoyl-3-methyl-1-phenyl-2-pyrazolin-5-one in different organic solvents. We have determined the fluorescence quantum yields, the natural lifetimes of the excited states, and the molar extinction coefficients for the complexes. __________ Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 42, No. 3, pp. 162–167, May–June, 2006.     

Synthesis and properties of 1-methyl-2-phenyl-5-(2-furyl)- and 1-methyl-2-phenyl-5-(2-thienyl)imidazoles

2-Phenyl-5-(2-furyl)- and 2-phenyl-5-(2-thienyl)imidazoles were synthesized by condensation of 2-furoylmethyl and 2-thenoylmethyl acetates with benzaldehyde under the conditions of Weidenhagen reaction. The products were converted to N-methyl derivatives in the KOH-acetone system. The electrophilic substitution reactions of the products (acylation, bromination, nitration, sulfonation, hydroxymethylation) were studied.