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PubMed1978

Interactions of pyrazole and ethanol on norepinephrine metabolism in rat brain.

Single large doses of pyrazole (100-200 mg/kg) given either i.p. or orally caused a decrease in brain norepinephrine and 3-methoxy-4-hydroxyphenylethylene glycol sulfate, but no change in dopamine beta-hydroxylase activity. The effects were enhanced by daily administration for 3 to 4 days. Concomitant administration of ethanol prevented the effects. With smaller doses (50 mg/kg/day) given orally for several days, there was little or no change for 3 days, but after 6 days there was an increase in both parameters. Dopamine beta-hydroxylase activity was also increased. The daily administration of ethanol alone (6.0 g/kg/day) for 6 days caused increased norepinephrine, but 3-methoxy-4-hydroxyphenylene glycol sulfate was diminished and dopamine beta-hydroxylase was unaffected. When the two drugs were given simultaneously, steady-state levels of norepinephrine were unaltered, but the sulfate metabolite was increased as was dopamine beta-hydroxylase. The results suggest that pyrazole and/or ethanol, administered daily for 6 days, leads to adaptive responses in catecholamine metabolism. Pyrazole (or a metabolite) has marked effects of its own, some or all of which are independent of its effects on alcohol dehydrogenase. When the two drugs are administered together, it is difficult to know whether the observed changes are independent or overlapping effects.

Animals↗

PubMed1984

Synergistic inhibition of leukemia L1210 cell growth in vitro by combinations of 2-fluoroadenine nucleosides and hydroxyurea or 2,3-dihydro-1H-pyrazole[2,3-a]imidazole.

9-beta-D-Arabinofuranosyl-2-fluoroadenine (2-F-ara-A) and 2-fluoro-2'-deoxyadenosine (2-FdAdo) were potent inhibitors of L1210 cell growth in culture. Even though these 2-fluoroadenine nucleosides are very poor substrates for adenosine deaminase, erythro-9-(2-hydroxyl-3-nonyl)adenine potentiated the growth-inhibitory properties of 2-FdAdo but not 2-F-ara-A in a synergistic manner. 2-FdAdo and 2-F-ara-A inhibited the conversion of [3H]cytidine to deoxycytidine nucleotides and incorporation into DNA, suggesting that ribonucleotide reductase was an intracellular site of action. 2-F-ara-A (6 microM) in combination with 2,3-dihydro-1H-pyrazole[2,3-a]imidazole gave synergistic inhibition of L1210 cell growth. At lower concentrations of 2-F-ara-A, the inhibition by this combination was only additive. The addition of Desferal to the combination of 2-F-ara-A plus 2,3-dihydro-1H-pyrazole[2,3-a]imidazole provided a strong synergistic combination. Similar results were obtained with combinations which included F-ara-A, hydroxyurea, and Desferal. The combinations of 2-FdAdo plus 2,3-dihydro-1H-pyrazole[2,3-a]imidazole or hydroxyurea gave strong synergistic inhibition of L1210 cell growth, even at the lowest concentration of 2-FdAdo (0.6 microM) studied. The presence of Desferal in the combination served to further potentiate the synergism.

Animals↗

PubMed1978

Synthesis of some substituted pyrazole-3-carboxylic acids with possible hypoglycemic and antimicrobial activity.

Condensation of delta-unsaturated 1.3-diketoesters (1) with 4-substituted arylhydrazines (2) or benzenesulphonyl-hydrazine (8) led to 1-aryl-3-ethoxycarbonyl-5-[alpha-substituted styryl]-pyrazoles (3), and 1-benzenesulphonyl-3-ethoxycarbonyl-5-styryl pyrazole (9). Potassium permanganate oxidation of 3 gave 5-acetyl (or benzoyl)-1-aryl-3-ethoxycarbonyl pyrazoles (6) which on hydrolysis gave the corresponding carboxylic acids (7). Hydrolysis of 3 gave the corresponding acids 4 which on treatment with thionyl chloride followed by ammonia afforded the corresponding carboxamides 5.

Anti-Infective Agents↗

PubMedDate not supplied

[The effect of pyrazole on the conformational state of cell membrane phospholipids].

A change of conformation of phospholipids in the presence of pyrazole was studied by the method of 1H-NMR spectroscopy with the use of hydrophilic paramagnetic probes Pr3+. It was shown that the ratio of transformation of the polar groups of the bilayer surface of sonicated phosphatidyl-choline increased in the presence of pyrazole as compared to the experimental values of the induced pseudocontact shifts of the phosphorylcholine groups. It was established that the earlier discovered complexes of pyrazole-phospholipids in the inert solution exhibited in the water phase.

Cell Membrane↗

PubMedDate not supplied

[Lipid spectrum of rat liver and brain after administration of pyrazole].

The effect of pyrazole (360 mg/kg, intraperitoneally) on the levels of lipid fractions was studied in the rat liver and brain. There were no differences in hepatic lipid levels after administration of pyrazole alone and in combination with ethanol (20% solution, 1 g/ kg body weight, intragastrically). Pyrazole alone or in combination with alcohol elevates the concentrations of cholesterol, total phospholipids, phosphatidylethanolamine, and cerebrosides III, reduces the levels of sphingomyelin and cardiolipin.

Alcohol Dehydrogenase↗

PubMed2003

Electronic coupling in a highly preorganized bimetallic complex comprising pyrazolate-bridged CpMn(CO)2 moieties.

By means of a multistep synthetic procedure a dimanganese complex has been prepared, in which a N,N'-bridging pyrazolate ligand spans two CpMn(CO)(2) subunits in a highly preorganized chelate arrangement. The Xray crystallographic analyses of the Mn(I)Mn(I) complex K(+)1(-) and of its non-chelate precursor complex elucidate details of the molecular structure, in particular an unusual pyrazolate binding mode in the solid state and intertwining of the CO ligands in the crowded bimetallic array 1(-). The Mn(I)Mn(I) compound (1(-)), the mixed-valent Mn(I)Mn(II) (1), and the oxidized Mn(II)Mn(II) form (1(+)) have been characterized by various analytical and spectrosopic methods, such as electrochemistry, variable-temperature EPR spectroscopy, IR spectroelectrochemistry, and UV/Vis/NIR spectroelectrochemistry as well as by DFT and TD-DFT calculations. Strong electronic coupling in the mixed-valent complex is observed, but time- (and temperature-) dependent valence detrapping occurs, thus placing 1 in class II according to the Robin and Day assignment, close to the class II/III transition. From variable-temperature EPR spectroscopy a rough estimate of the activation energy and rate for thermal electron transfer can be deduced, with E(th) ( not equal )=13.6 kJ mol(-1) and k(th)=2.6 x 10(10) s(-1) at 298 K. Unexpectedly, no intervalence CT transition for 1 is detected in solution, but one appears in the optical spectrum of solid 1. The conclusions drawn from experiments are fully supported by DFT calculations that were carried out for all three forms of the dimanganese complex. A broken symmetry treatment for mixed-valent 1 reveals almost perfect localization of both spin and charge on one Mn center. According to TD-DFT the first excited states of 1 give rise to the IT processes in the NIR-energy region, as observed in the solid-state spectrum. The HOMOs are located at the Mn ions and are favorably arranged for pi interactions with the bridging pyrazolate.

Journal Article↗

PubMed2003

Synthesis and properties of rhenium carbonyl complexes of alpha,alpha'-bis[(1-pyrenyl)pyrazol-1-yl]alkane ligands.

The reaction between (1-acetyl)pyrene and dimethylformamide dimethylacetal followed by condensation of the resulting product mixture with hydrazine affords 3(5)-(1-pyrenyl)pyrazole (2) in good yield. The easily separable bis[(1-pyrenyl)pyrazole]methane derivatives CH(2)(3-pz(pyrene))(2) (3a, pz = pyrazolyl ring) and CH(2)(3-pz(pyrene))(5-pz(pyrene)) (3b) were prepared by metathetical reactions between pyrazole and CH(2)Cl(2), while CH((n)()Pr)(pz(pyrene))(2) (4) was prepared by transamination of 2 with butyraldehyde diethylacetal. Compounds 2-4 are luminescent under irradiation with UV light and have pyrenyl monomer-based emissions centered near 400 nm. Compounds 3a and 4 each react with Re(CO)(5)Br in a 1:1 molar ratio to form highly insoluble complexes Re(CO)(3)Br[(pz(pyrene))(2)CH(2)] (5) and Re(CO)(3)Br[(pz(pyrene))(2)CH((n)()Pr)] (6). Complex Re(CO)(3)Br[(pz)(2)CMe(2)] (7) was also prepared. X-ray structural studies of 6 show extensive pi-stacking of pyrenyl groups to form two-dimensional sheets. Pulsed field gradient spin-echo NMR (PGSE-NMR) experiments show that the complexes are monomeric in tetrachloroethane. Variable-temperature, difference NOE and 2-D NMR experiments demonstrate that isomers are present in solution that differ by restricted rotation about the pyrazolyl-pyrenyl bond. The pyrenyl-based emissions centered near 400 nm are quenched by complexation to the Re(CO)(3)Br moiety in 5 and 6.

Journal Article↗

PubMed2006

Supramolecular structures and columnar mesophase induction in nondiscoid pyrazoles by complexation to rhodium(I).

Several new cis-[RhCl(CO)2(Ln)] complexes have been prepared using different polycatenar pyrazole ligands (Ln) in order to obtain columnar liquid crystalline arrangements. The topology of the ligand plays an essential role, and a mesophase is induced at room temperature from a nonmesogenic pyrazole only when it is symmetrically substituted with six decyloxy chains. The single-crystal structure of a methoxy-substituted analogue, 3,5-bis(3,4,5-trimethoxyphenyl)pyrazole, is formed by globular tetrameric structures held together by H-bonding. However, parallel dimers are present in the corresponding cis-chlorodicarbonylrhodium(I) complex, a situation that explains the induction of a columnar mesophase in the decyloxy-substituted complex. The XRD pattern of the mesophase is consistent with a hexagonal symmetry in which the columns are formed by molecules assembled in an antiparallel mode. The crystal-to-mesophase transition was also detected by spectroscopic techniques as a shift in the IR carbonyl stretching bands and the appearance of a charge-transfer band in the absorption spectrum with thermochromic behavior.

Journal Article↗

PubMed1996

Synthesis and Characterization of Heterodinuclear IrCo, RuCo, IrNi, and RuNi Complexes Containing Pyrazolate and Pyrazolylborate Ligands.

Treatment of the metallo ligands [ML(pz)(2)(Hpz)] (pz = pyrazolate; L = C(5)Me(5), M = Ir (1); L = mesitylene, M = Ru (3)) with [M'Cl{HB(3-i-Pr-4-Br-pz)(3)}] (M' = Co (4), Ni (5)) yields heterodinuclear complexes of formula [LM(&mgr;-pz)(2)(&mgr;-Cl)M'{HB(3-i-Pr-4-Br-pz)(3)}] (L = C(5)Me(5); M = Ir; M' = Co (6), Ni (7). L = mesitylene; M = Ru; M' = Co (8)). The related complex [Ru(eta(6)-p-cymene)(pz)(2)(Hpz)] (2) reacts with equimolar amounts of 4 or 5 to give mixtures of the corresponding bis(&mgr;-pyrazolato) &mgr;-chloro complexes [(eta(6)-p-cymene)Ru(&mgr;-pz)(2)(&mgr;-Cl)M'{HB(3-i-Pr-4-Br-pz)(3)}] (M' = Co (9), Ni (10)) and the triply pyrazolato-bridged complexes [(eta(6)-p-cymene)Ru(&mgr;-pz)(3)M'{HB(3-i-Pr-4-Br-pz)(3)}] (M' = Co (11), Ni (12)). Complex 1 reacts with 5 in the presence of KOH to give the IrNi complex [(eta(5)-C(5)Me(5))Ir(&mgr;-pz)(3)Ni{HB(3-i-Pr-4-Br-pz)(3)}] (13) whereas its reaction with 4 and KOH rendered the bis(&mgr;-pyrazolato) &mgr;-hydroxo complex [(eta(5)-C(5)Me(5))Ir(&mgr;-pz)(2)(&mgr;-OH)Co{HB(3-i-Pr-4-Br-pz)(3)}] (14). The molecular structure of the heterobridged IrCo complex (6) and those of the homobridged RuNi (12) and IrNi (13) complexes have been determined by X-ray analyses. Compound 6 crystallizes in the monoclinic space group P2(1)/n, with a = 10.146(5) Å, b = 18.435(4) Å, c = 22.187(13) Å, beta = 97.28(4) degrees, and Z = 4. Complex 12 is monoclinic, space group P2(1), with a = 10.1169(7) Å, b = 21.692(2) Å, c = 11.419(1) Å, beta = 112.179(7) degrees, and Z = 2. Compound 13 crystallizes in the monoclinic space group Cc, with a = 13.695(2) Å, b = 27.929(6) Å, c = 13.329(2) Å, beta = 94.11(4) degrees, and Z = 4. All the neutral complexes 6, 12, and 13 consist of linear M.M'.B backbones with two (6) or three (12, 13) pyrazolate ligands bridging the dimetallic M.M' units and three substituted 3-i-Pr-4-Br-pz groups joining M' to the boron atoms. The presence in the proximity of the first-row metal M' of the three space-demanding isopropyl substituents of the pyrazolate groups induces a significant trigonal distortion of the octahedral symmetry, yielding clearly different M'-N bond distances on both sides of the ideal octahedral coordination sphere of these metals.

Journal Article↗

PubMed1999

Formation of Dinuclear Copper(II) Complexes from a Macrocycle with Built-in Pyrazole Groups.

The 22-membered macrocycle, containing four endocyclic pyrazole groups and two exocyclic pyridine groups, viz. (9,22-di(pyridin-2-ylmethyl)-1,4,9,14,17,22,27,28,29,30-decaaza-5,13,18,26-tetramethyl)pentacyclo[24.2.1.1(4,7).1(11,14).1(17,20)]triacontane-5,7(28),11(29),12,18,20(30),24(27),25-octaene (MePy22Pz), has been synthesized in an eleven-step procedure. Two dinuclear copper(II) compounds, viz. [Cu(2)(MePy22Pz)(NO(3))(4)](MeOH)(2) (A) and [Cu(2)(MePy22Pz)(CF(3)SO(3))(2)(H(2)O)(2)](CF(3)SO(3))(2)(MeOH)(2) (B), were prepared with this macrocycle. In both compounds the copper(II) ions are in a square pyramidal N(3)O(2) environment involving a pyrazole nitrogen, a pyridine nitrogen, and a tertiairy amine nitrogen and two oxygen atoms, which stem from two different nitrate anions in compound A and from a triflate anion and a water molecule in compound B. Two of the four pyrazole groups of the macrocycle do not participate in the coordination. The pendent pyridine groups protrude on opposite sides of the macrocycle. Consequently, the copper ions are on different sides of the macrocyclic ring and quite far apart with Cu-Cu distances of 8.668(4) Å in A and 6.814(1) Å in B.

Journal Article↗

PubMed2003

A novel one-pot method for the preparation of pyrazoles by 1,3-dipolar cycloadditions of diazo compounds generated in situ.

A convenient one-pot procedure for the preparation of pyrazoles by 1,3-dipolar cycloaddition of diazo compounds generated in situ has been developed. Diazo compounds derived from aldehydes were reacted with terminal alkynes to furnish regioselectively 3,5-disubstituted pyrazoles. Furthermore, the reaction of N-vinylimidazole and diazo compounds derived from aldehydes gave exclusively 3-substituted pyrazoles in a one-pot process.

Journal Article↗

PubMed2005

Dichlorotetrakis[3-(4-pyridyl)-1H-pyrazole]cobalt(II) acetonitrile tetrasolvate: an infinite hydrogen-bonded network, in an instant.

Reaction of 3-(4-pyridyl)pyrazole (4pypz) with cobalt(II) chloride in acetonitrile affords the title complex, [CoCl(2)(C(8)H(7)N(3))(4)].4CH(3)CN, within seconds of addition, as purple X-ray quality crystals. The molecule has C4 symmetry. The metal ion exhibits a trans-N(4)Cl(2) octahedral geometry, with the four 3-(4-pyridyl)-1H-pyrazole ligands coordinating through their pyridyl N-atom donors; one coordinated chloride ion forms hydrogen bonds with the pyrazole rings from four separate units. This configuration creates an infinite three-dimensional coordination network containing channels that are filled with acetonitrile solvent molecules.

Journal Article↗

PubMed2004

QSAR analysis of some fused pyrazoles as selective cyclooxygenase-2 inhibitors: a Hansch approach.

Quantitative structure activity relationships (QSAR) for two unique series of centrally fused pyrazole ring systems have been studied for selective cyclooxygenase-2 inhibitory activity. Several statistically significant QSAR models were developed and suggest that hydrophobicity of entire molecules and a fluorine atom substitution at position 8 of the non benzene sulphonyl ring fused with central pyrazole core of series 1 compounds is crucial for improved COX-2 selectivity. Various structural and physicochemical stipulations to improve the inhibitory activities of the enzymes among individual series of compounds are also discussed. The conclusions derived may serve as an example to advance the design of new selective COX-2 inhibitors.

Algorithms↗

PubMed2006

Synthesis and molluscicidal activity of some 1,3,4-triaryl-5-chloropyrazole, pyrano[2,3-c]pyrazole, pyrazolylphthalazine and pyrano[2,3-d]thiazole derivatives.

2-(5-Chloro-1,3-diphenyl-1H-pyrazol-4-ylmethylene)-malononitrile 1a reacts with the arylidenes of malononitrile 2a-d to afford the triaryl-5-chloropyrazoles 3a-d, respectively. 1a reacts with the active methylene pyrazolinones 5a, b and 12a, b to afford different products 8, 9, 10, 11, and 14a, b--depending on the substitution in the pyrazole ring. Compound 1a reacts also with the pyridazinone derivative 15 to afford the phthalazinone 16, and with the thiazolinones 17a-c to afford the pyrano[2,3-d]thiazoles 20a-c, respectively. It reacts also with the malononitrile dimer 21a and with ethyl cyanoacetate dimer 21b to yield the pyrazolyl pyridines 22a, b, respectively. The synthesized compounds showed a moderate molluscicidal activity towards Biomphalaria alexandrina snails.

Animals↗

PubMed1991

Tricyclic heteroaromatic systems: [1]benzopyrano-pyrazol-4-ones as benzodiazepine receptor ligands.

The synthesis of a series of 8-substituted 1,4-dihydro-1-aryl-3-methyl-[1]benzopyrano[3,4-d]pyrazol-4-ones (series 7) 2,4-dihydro-2-aryl-3-methyl[1]benzopyrano[4,3-c]pyrazol-4-ones (series 8) is reported. Compounds of series 7 and 8 were tested for their ability to displace [3H]flunitrazepam from bovine brain membranes and for their in vitro biological activity. The results allowed some conclusions to be drawn about the structural requirements of the benzodiazepine recognition site within this class of unusual ligands.

Animals↗

PubMed2006

A 1H, 13C and 15N NMR study in solution and in the solid state of six N-substituted pyrazoles and indazoles.

Three N-substituted pyrazoles and three N-substituted indazoles [1-(4-nitrophenyl)-3,5-dimethylpyrazole (1), 1-(2,4-dinitrophenyl)-3,5-dimethylpyrazole (2), 1-tosyl-pyrazole (3), 1-p-chlorobenzoylindazole (4), 1-tosylinda-zole (5) and 2-(2-hydroxy-2-phenylethyl)-indazole (6)] have been studied by NMR spectroscopy in solution (1H, 13C, 15N) and in the solid state (13C, 15N). The chemical shifts have been compared with GIAO/DFT calculated absolute shieldings. Some discrepancies have been analyzed.

Carbon Isotopes↗

PubMed2001

High-resolution analysis of a 144-membered pyrazole library from combinatorial solid phase synthesis by using electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry.

A compound library consisting of 144 pyrazole carboxylic acids and six sublibraries consisting of 24 components was analysed using electrospray ionisation Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS). The library was synthesised by the split-mix method and investigated by direct infusion analysis by which 134 compounds were detected. FTICR-MS is predestined for the direct characterisation of complex compound libraries because of its outstanding mass resolution and mass accuracy. However, discrimination within the electrospray ionisation process sometimes leads to signal suppression and thus to misinterpretation of the synthetic results. Using micro-HPLC/MS we were able to assign all 144 compounds including all pairs of isobaric pyrazoles. We also show that, due to partial separation, FTICR-MS is indispensable for proper detection of co-eluting compounds.

Chromatography, High Pressure Liquid↗

PubMed1986

Coumarin 7-hydroxylase in inbred strains of mice: comparison with other microsomal monooxygenase activities and induction by pyrazole.

This study was carried out in order to find out the effects of pyrazole on liver drug metabolism in several inbred mice: D2, B6, BALB, and AKR and in the outbred mouse NMRI. Compared to control pyrazole treatment decreased the microsomal cytochrome P-450 content of liver to 60-70% and benzo(a)pyrene hydroxylase and ethylmorphine N-demethylase activities to 40-55% and increased 7-ethoxycoumarin O-deethylase activity to 100-200% in AKR, BALB, B6, and NMRI mice and 300% in D2 mouse. Coumarin 7-hydroxylase was increased only 200-300% in B6, AKR, and BALB mice and as much as 700% in D2 and 900% in NMRI mice compared to control. Coumarin 7-hydroxylase is under different genetic control from other monooxygenase activities and differently expressed in various strains of mice.

Animals↗