Quantification of Paraquat, MPTP, and MPP+ in brain tissue using microwave-assisted solvent extraction (MASE) and high-performance liquid chromatography–mass spectrometry

Animal models, consistent with the hypothesis of direct interaction of paraquat (PQ) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) with specific areas of the central nervous system have been developed to study Parkinson’s disease (PD) in mice. These models have necessitated the creation of an analytical method for unambiguous identification and quantitation of PQ and structurally similar MPTP and 1-methyl-4-phenylpyridinium ion (MPP⁺) in brain tissue. A method for determination of these compounds was developed using microwave-assisted solvent extraction (MASE) and liquid chromatography–mass spectrometry. Extraction solvent and microwave conditions such as power and time were optimized to produce recoveries of 90% for PQ 78% for MPTP and 97% for its metabolite MPP⁺. The chromatographic separation was performed on a C8, column and detection was carried out using an ion trap as an analyzer with electrospray ionization. Mass spectrometer parameters such as heated capillary temperature, spray voltage, capillary voltage and others were also optimized for each analyte. Analysis was done in selective ion-monitoring (SIM) mode using m/z 186 for PQ, m/z 174 for MPTP, and m/z 170 for MPP⁺. The method detection limit for paraquat in matrix was 100 pg, 40 pg for MPTP, and 20 pg MPP⁺.     

Protective Effects and Mechanisms of Procyanidins on Parkinson’s Disease In Vivo and In Vitro

This research assessed the molecular mechanism of procyanidins (PCs) against neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its metabolite 1-methyl-4-phenylpyridinium (MPP⁺) induced Parkinson’s disease (PD) models. In vitro, PC12 cells were incubated with PCs or deprenyl for 24 h, and then exposed to 1.5 mM MPP⁺ for 24 h. In vivo, zebrafish larvae (AB strain) 3 days post-fertilization (dpf) were incubated with deprenyl or PCs in 400 μM MPTP for 4 days. Compared with MPP⁺/MPTP alone, PCs significantly improved antioxidant activities (e.g., glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT)), and decreased levels of reactive oxygen species (ROS) and malondialdehyde (MDA). Furthermore, PCs significantly increased nuclear Nrf2 accumulation in PC12 cells and raised the expression of NQO1, HO-1, GCLM, and GCLC in both PC12 cells and zebrafish compared to MPP⁺/MPTP alone. The current study shows that PCs have neuroprotective effects, activate the nuclear factor-erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway and alleviate oxidative damage in MPP⁺/MPTP-induced PD models.     

PEP-1-GLRX1 Reduces Dopaminergic Neuronal Cell Loss by Modulating MAPK and Apoptosis Signaling in Parkinson’s Disease

Parkinson’s disease (PD) is characterized mainly by the loss of dopaminergic neurons in the substantia nigra (SN) mediated via oxidative stress. Although glutaredoxin-1 (GLRX1) is known as one of the antioxidants involved in cell survival, the effects of GLRX1 on PD are still unclear. In this study, we investigated whether cell-permeable PEP-1-GLRX1 inhibits dopaminergic neuronal cell death induced by 1-methyl-4-phenylpyridinium (MPP⁺) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We showed that PEP-1-GLRX1 protects cell death and DNA damage in MPP⁺-exposed SH-SY5Y cells via the inhibition of MAPK, Akt, and NF-κB activation and the regulation of apoptosis-related protein expression. Furthermore, we found that PEP-1-GLRX1 was delivered to the SN via the blood–brain barrier (BBB) and reduced the loss of dopaminergic neurons in the MPTP-induced PD model. These results indicate that PEP-1-GLRX1 markedly inhibited the loss of dopaminergic neurons in MPP⁺- and MPTP-induced cytotoxicity, suggesting that this fusion protein may represent a novel therapeutic agent against PD.     

Electronic and Conformational Effects on the Lipophilicity of Isomers and Analogs of the Neurotoxin 1-Methyl-4-phenylpyridinium (MPP+)

A number of isomers and analogs of the neurotoxin 1-methyl-4-phenylpyridinium (MPP⁺) were examined for their lipophilic behavior. Their partition coefficients in the 1-octanol/H₂O system were measured by centrifugal partition chromatography (CPC), which, being much faster and markedly more precise than the classical shake-flask method, proved a very promising alternative for assessing lipophilicity. A smaller-than-expected lipophilicity was shown by the ortho-isomer of MPP⁺ (M2PP⁺) and is explained in terms of electronic effects and rigidity, as revealed by UV and NMR spectroscopy, and conformational analysis. Implications of lipophilicity in modulating the in vivo dopaminergic neurotoxicity of the examined compounds are also discussed.     

Reactions with diazoazoles. Part VI. Unequivocal synthesis of 3-methyl-3h-azolotetrazoles. Correction of the formerly described 3-methylazolotetrazoles in favour of mesoionic 2-methylazolotetrazoles

3-Methyl-3H-pyrazolo[1,5-d]tetrazoles 2 and 3-methyl-6-phenyl-3H-1,2,4-triazolo[1,5-d]tetrazole (4) have been unequivocally synthesized by annulation of the tetrazole moiety to the pyrazole resp. 1,2,4-triazole system. The constitution of some N-methyl substituted azolotetrazoles, formerly described as 3-methyl-3H-pyrazolo[1,5-d]tetrazoles 2, 3-methyl-6-phenyl-3H-1,2,4-triazolo[1,5-d]tetrazole (4) and 1-methyl-6-phenyl-1H-1,2,4-triazolo[4,3-d]tetrazole (5), has to be revised in favour of the corresponding mesoionic 2-methyl derivatives 2′, 4′, 5′. The structures of 3-methyl-3H- as well as of 2-methyl-2H-pyrazolo[1,5-d]tetrazole derivatives 2a, 2c, 2′a have been determined by X-ray analyses. The azapentalenic system is aromatic in all three measured compounds and mesoionic in the case of the 2-methyl-2H- substitution pattern. The phenyl and ester substituents are coplanar with the azapentalene system. 3-, 2-, and 1-Methylpyrazolo[1,5-d]tetrazoles exhibit different behaviour when allowed to react with stannous chloride or sodium ethoxide. Azolotetrazoles with a methyl substituent at N-1, N-2 or N-3 of the tetrazole moiety can be distinguished by a combination of ¹H and ¹³C nmr with respect to the chemical shifts of the N-methyl group and the bridgehead carbon. Results of semiempirical calculations of the pyrazolo[1,5-d]tetrazole anion and of its N-methyl derivatives are discussed.     

Synthesis of 1,4-dihydro-4-methyl-1-phenyl-5H-1,3,4-benzotriazepin-5-ones

The synthesis of 1,4-dihydro-4-methyl-1-phenyl-5H-1,3,4-benzotriazepin-5-one ( 4a ) and its 8-chloro analog ( 4b ) is described. Attempted synthesis of the 2-methyl analog of 4a from 2-(phenylamino)benzoic acid 1-methylhydrazide ( 10 ) and triethyl orthoaeetate led only to the Schiff base intermediate, 2-(phenylamino)benzoic acid 2-(1-ethoxyethylidene)-1-methylhydrazide ( 11 ). Cyclization of 11 was attempted unsuccessfully with a variety of reagents. The intere?ting reaction products from the treatment of 11 with trifluoroacetic acid are described.     

Catalytic Potential of Pyrazolone Based Dioxidomolybdenum(VI) Complexes for Multicomponent Biginelli Reactions,Epoxidation of Olefins and Oxidative Bromination of Phenol Derivatives

Three different types of dioxidomolybdenum(VI) complexes of 4-acetyl-3-methyl-1-phenyl-5-pyrazolone (Hmp, I )), 3-methyl-1-phenyl-4-propionyl-5-pyrazolone (Hpp, II ), 4-butyryl-3-methyl-1-phenyl-5-pyrazolone (Hbutp, III ), and 4-isobutyryl-3-methyl-1-phenyl-5-pyrazolone (isobutp, IV ) have been isolated and characterized by various spectroscopic (FT-IR, UV/Vis, ¹H and ¹³C NMR) techniques, thermal analysis and single crystal X-ray analysis. These complexes adopt a distorted six-coordinate octahedral geometry where ligands act as bidentate, coordinating through the two O atoms. These complexes have been used as catalysts to explore a single pot multicomponent (benzaldehyde or its derivatives, urea/thiourea and ethyl acetoacetate/phenyl acetoacatate) Biginelli reaction producing biologically active 3,4-dihydropyrimidin-2-(1H)-one and 3,4-dihydropyrimidin-2-(1H)-thione based biomolecules under solvent-free conditions. Presence of H₂O₂ improves the yield of dihydropyrimidin-2-(1H)-one but it acts as poison for the later molecule. Epoxidation of internal and terminal alkenes mainly resulted in the formation of the corresponding epoxide. The catalytic oxidative bromination of thymol, a reaction facilitated by vanadium dependent haloperoxidases, resulted in the formation of three product namely 2-bromothymol, 4-bromothymol and 2,4-bromothymol. Other phenol derivatives have also been brominated effectively.     

Neuroprotective Effects of B-Type Cinnamon Procyanidin Oligomers on MPP+-Induced Apoptosis in a Cell Culture Model of Parkinson’s Disease

Cinnamon procyanidin oligomers (CPOs) are water-soluble components extracted from cinnamon. This study aims to explore the neuroprotection of B-type CPO (CPO-B) against 1-methyl-4-phenylpyridinium (MPP⁺)-mediated cytotoxicity and the molecular mechanisms underlying its protection. The results demonstrated that CPO-B showed protection by increasing cell viability, attenuating an intracellular level of reactive oxygen species, downregulating cleaved caspase-3 expression, and upregulating the Bcl-2/Bax ratio. Moreover, CPO-B completely blocked the dephosphorylation of extracellular, signal-regulated kinase 1 and 2 (Erk1/2) caused by MPP⁺. Treatment with an Erk1/2 inhibitor, SCH772984, significantly abolished the neuroprotection of CPO-B against MPP⁺. Taken together, we demonstrate that CPO-B from cinnamon bark provided protection against MPP⁺ in cultured SH-SY5Y cells, and the potential mechanisms may be attributed to its ability to modulate the dysregulation between pro-apoptotic and anti-apoptotic proteins through the Erk1/2 signaling pathway. Our findings suggest that the addition of cinnamon to food or supplements might benefit patients with PD.     

Synthesis of certain 1,2,4-triazole nucleoside derivatives

The syntheses of 3-amino-4-methyl-1-(β-D-ribofuranosyl)-1,2,4-triazolin-5-one ( 8a ) and its 2′-deoxy analog 8b as well as 5-amino-2-methyl-1-(β-D-ribofuranosyl)-1,2,4-triazolin-3-one ( 12 ) have been accomplished. Compounds 8a and 8b were synthesized via glycosylation of 3-bromo-5-nitro-1,2,4-triazole which was followed by replacement in three steps of the 3-bromo function to yield 3-nitro-1-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-1,2,4-triazolin-5-one ( 4a ) and its 2′-deoxy analog 4b . Compounds 4a and 4b were methylated at N², hydrogenated and deblocked to give 3-amino-4-methyl-1-(β-D-ribofuranosyl)-1,2,4-triazolin-5-one ( 8a ) and the 2′-deoxy analog 8b . Compound 12 was synthesized by glycosylation of 3-amino-1-methyl-1,2,4-triazolin-5(2H)-one ( 10 ). The structures of 8b and 12 were confirmed by single crystal X-ray diffraction analysis.     

Suppressing Cdk5 Activity by Luteolin Inhibits MPP+-Induced Apoptotic of Neuroblastoma through Erk/Drp1 and Fak/Akt/GSK3β Pathways

Parkinson’s disease (PD) is characterized by the progressive degeneration of dopaminergic neurons. The cause of PD is still unclear. Oxidative stress and mitochondrial dysfunction have been linked to the development of PD. Luteolin, a non-toxic flavonoid, has become interested in an alternative medicine, according to its effects on anti-oxidative stress and anti-apoptosis, although the underlying mechanism of luteolin on PD has not been fully elucidated. This study aims to investigate whether luteolin prevents neurotoxicity induction by 1-methyl-4-phenylpyridinium iodide (MPP⁺), a neurotoxin in neuroblastoma SH-SY5Y cells. The results reveal that luteolin significantly improved cell viability and reduced apoptosis in MPP⁺-treated cells. Increasing lipid peroxidation and superoxide anion (O₂⁻), including mitochondrial membrane potential (Δψm) disruption, is ameliorated by luteolin treatment. In addition, luteolin attenuated MPP⁺-induced neurite damage via GAP43 and synapsin-1. Furthermore, Cdk5 is found to be overactivated and correlated with elevation of cleaved caspase-3 activity in MPP⁺-exposed cells, while phosphorylation of Erk1/2, Drp1, Fak, Akt and GSK3β are inhibited. In contrast, luteolin attenuated Cdk5 overactivation and supported phosphorylated level of Erk1/2, Drp1, Fak, Akt and GSK3β with reducing in cleaved caspase-3 activity. Results indicate that luteolin exerts neuroprotective effects via Cdk5-mediated Erk1/2/Drp1 and Fak/Akt/GSK3β pathways, possibly representing a potential preventive agent for neuronal disorder.     

Synergistic solvent extraction of lanthanides with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one and aliphatic amines: Influence of the ammonium salt ions

Summary The synergistic solvent extraction of Pr, Gd, and Yb with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (HP) and tridodecylammonium (TDAHA), trioctylammonium (TOAHA), and dioctylammonium (DOAHA) salts (A ^–=Cl^–, NO ₃ ^– , and ClO ₄ ^– ) in C₆H₆ has been studied. The composition of the extracted species has been determined asAmH⁺[LnP ₄]^– (AmH⁺: ammonium salt cation). The values of the equilibrium constant have been calculated. The influence of the ammonium salt ions on the extraction process is discussed.

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Synergetische Extraktion von Lanthaniden mit Mischungen aus 1-Phenyl-3-methyl-4-benzoyl-pyrazol-5-on und aliphatischen Aminen: Einfluß der Ammoniumsalzionen

Zusammenfassung Die synergetische Extraktion von Pr, Gd und Yb mit Mischungen aus 1-Phenyl-3-methyl-4-benzoyl-pyrazol-5-on (HP) und Tridodecylammonium-(TDAHA), Trioctylammonium-(TOAHA) und Dioctylammoniumsalzen (DOAHA) (A ^–=Cl^–, NO ₃ ^– und ClO ₄ ^– ) in C₆H₆ wurde untersucht. Die Zusammensetzung der Extraktionskomplexverbindungen wurde zuAmH⁺[LnP ₄]^– bestimmt; die Gleichgewichtskonstanten wurden berechnet. Der Einfluß der Ionen des Ammoniumsalzes auf die Extraktion wird diskutiert.

     

Application of photoelectron spectroscopy to biologically active molecules and their constituent parts. II. 1,4-Benzodiazepines

The Hel photoelectron (PE) spectra of 5-phenyl-7-chloro-2H-1,4-benzodiazepin-2-one ( 1 ), its 1-methyl derivative ( 2 ), 3-hydroxy derivative ( 3 ), 1-methyl-3-hydroxy derivative ( 4 ), 3-(S)-methyl derivative ( 5 ), and 1-methyl-3-(S)-methyl derivative ( 6 ) have been recorded. The electronic structure of these compounds is discussed on the basis of the observed ionization energies, and of the semiempirical CNDO/2 calculations on model compounds 1a-6a , which have a hydrogen instead of the phenyl group in the 5-position. As a result the character of the seven highest occupied orbitals in 1–6 have been assigned.     

7-Azaindole derivatives

The Bischler-Napiralski reaction is used to synthesize 1-phenyl-3, 9-dimethyl-5, 6-dihydro-12-aza--carboline, and its 5-methyl and 5-ethyl derivatives, from 1-phenyl-4-methyl-3-aminoalkyl-T-azaindoles. 5, 6-Dihydro-12-aza--carbolines prepared by sodium borohydride reduction are converted into 1-phenyl-3, 9-dimethyl-3, 4, 5, 6-tetrahydro-12-aza--carboline and its 5-methyl and 5-ethyl derivatives. 1-Phenyl-9-methyl-12-azaharman is synthesized by palladium dehydrogenation of 1-phenyl-3, 9-dimethyl-5, 6-dihydro-12-aza--carboline.For Part XVII see [1].     

原位生成的Ph3C+均相有机催化剂催化4,4’-芳亚甲基-二（3-甲基-1-苯基-1H-吡唑-5-醇）高效合成（英文）简

Trityl chloride (Ph₃CCl) efficiently catalyzes the condensation of 3-methyl-1-phenyl-1H-pyrazol- 5(4H)-one and aromatic aldehydes under mild and solvent-free conditions, affording 4,4''- (arylmethylene)-bis(3-methyl-1-phenyl-1H- pyrazol-5-ol)s in high to excellent yields and in short reaction time. The presence of the requisite organocatalytic trityl carbocation (Ph₃C⁺) species was confirmed by analysis of infrared, ¹H NMR, and ultra violet spectral data. A plausible mechanism was proposed for the reaction based on the observations and literature precedent.     

Synthesis and structures of iron(iii) complexes based on azo derivatives of 5-oxo- and 5-thioxopyrazole

New potentially tridentate ligands, viz., 3-methyl-1-phenyl-4-(quinolin-8-ylhydrazono)pyrazol-5(1H)-one and 3-methyl-1-phenyl-4-(quinolin-8-ylhydrazono)pyrazole-5(1H)-thione (LH), and their complexes with Fe^III were synthesized. The structures of the ligands and metal chelates (FeL₂A; A = ClO₄ or FeCl₄) were studied by ¹H NMR spectroscopy and magnetochemistry. The FeL₂A complex (A = FeCl₄) was investigated by X-ray diffraction. These low-spin complexes have pseudooctahedral structures with the N₄X₂ ligand environment (X = O or S).     

Hydrazine-hydrazone tautomerism in phenylhydrazinopyrimidones

4-Phenylhydrazino-2-pyrimidone and its 1-methyl analog have been shown by ¹H nmr to exist in intercon-verting hydrazine and hydrazone tautomers in deuteriodimethylsulfoxide solution. Solvent effects indicate that increasing solvent polarity favors the hydrazine forms. In contrast, the 3-methyl analog occurs exclusively as the hydrazone. The hydrazone forms of the parent and 1-methyl derivatives appear to adopt the syn rotamers as a result of intramolecular hydrogen bonding. Variable temperature studies showed relatively high free energy barriers to tautomerization in these compounds, resulting both from solvation and intramolecular hydrogen bonding. The ¹H nmr spectra of 1-methyl-4-hydrazino-2-pyrimidone suggest that it exists predominately as the hydrazone in deuteriodimethylsulfoxiderdeuteriochloroform solution, although the barrier to tautomerization is similar to those for the phenylhydrazino compounds.     

Synthesis and some properties of 6-di(tri)fluoromethyl-and 5-di(tri)fluoroacetyl-3-methyl-1-phenylpyrano[2,3-<Emphasis Type="Italic">c</Emphasis>]pyrazol-4(1<Emphasis Type="Italic">H</Emphasis>)-ones

Condensation of 4-acetyl-5-hydroxy-3-methyl-1-phenylpyrazole with R^FCO₂Et (R^F = CF₂H, CF₃) in the presence of LiH affords 4-di(tri)fluoroacetoacetyl-5-hydroxy-3-methyl-1-phenylpyrazoles from which 6-di(tri)fluoromethyl-and 5-di(tri)fluoroacetyl-3-methyl-1-phenylpyrano[2,3-c]pyrazol-4(1H)-ones were synthesized. The reactions of pyrano-pyrazoles with hydrazine hydrate, ethyl mercaptoacetate, or aromatic amines proceed at the C(6) atom with pyrone ring opening and formation of aminoenones, pyrazoles, or thiophenes with the 5-hydroxy-3-methyl-1-phenyl-4-pyrazolyl fragment. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2750–2754, December, 2005.     

Syntheses,characterization of and studies on the electrochemical behaviour of ferrocenyl dithiophosphonates and 4-methoxyphenyl dithiophosphonates

Some 1,3-dithiadiphosphetane 2,4-disulfides (X₂P₂S₄, X: Fc, FcLR; X: CH₃O?C₆H₄?, LR) were allowed to react with alcohols to obtain dithiophosphonic acids (X(OR)PS₂H). These were converted to the corresponding ammonium salts. The salts were of the structures [Fc(OR)PS₂]^?[NH₄]⁺, R: 3-methyl-1-butyl- for I; 1-phenyl-1-propyl- for II; 3-pentyl- for III; 3-phenyl-1-propyl- for IV and [CH₃O?C₆H₄(OR)PS₂]^?[NH₄]⁺, R: 3-methyl-1-butyl- for V and 1-phenyl-1-propyl- for VI. To the best of our knowledge, all the compounds except V were prepared for the first time.

The compounds synthesized were characterized by elemental analysis, NMR (¹H, ¹³C, ³¹P), MS, FTIR, and Raman spectroscopies. Electrochemical behaviors of I–VI at disposable pencil graphite electrode (PGE) were investigated by using cyclic voltammetry (CV) and square-wave voltammetry (SWV). Adsorption and diffusion patterns of all the compounds on the PGE were also studied.

Two electroactive groups were identified in the compounds I–IV and only one in V and VI. The ferrocenyl groups of I-IV were oxidized at around 0.4 V. The same compounds display a second, more intense CV band at 0.8 V. The corresponding band for the compounds V–VI appears at around 0.6 V with a much weaker intensity. It is suggested that the ferrocenyl group introduced into the structures stabilizes the radical species formed as the product of the oxidation of the dithiophosphonato group.     

A Novel Synthetic Precursor of Styryl Sulfone Neuroprotective Agents Inhibits Neuroinflammatory Responses and Oxidative Stress Damage through the P38 Signaling Pathway in the Cell and Animal Model of Parkinson’s Disease

A novel class of styryl sulfones were designed and synthesized as CAPE derivatives by our work team, which showed a multi-target neuroprotective effect, including antioxidative and anti-neuroinflammatory properties. However, the underlying mechanisms remain unclear. In the present study, the anti-Parkinson’s disease (PD) activity of 10 novel styryl sulfone compounds was screened by the cell viability test and the NO inhibition test in vitro. It was found that 4d exhibited the highest activity against PD among them. In a MPTP-induced mouse model of PD, the biological activity of 4d was validated through suppressing dopamine neurotoxicity, microglial activation, and astrocytes activation. With compound 4d, we conducted the mechanistic studies about anti-inflammatory responses through inhibition of p38 phosphorylation to protect dopaminergic neurons, and antioxidant effects through promoting nuclear factor erythroid 2-related factor 2 (Nrf2). The results revealed that 4d could significantly inhibit 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine/1-methyl-4-phenylpyridinium (MPTP/MPP⁺)-induced p38 mitogen-activated protein kinase (MAPK) activation in both in vitro and in vivo PD models, thus inhibiting the NF-κB-mediated neuroinflammation-related apoptosis pathway. Simultaneously, it could promote Nrf2 nuclear transfer, and upregulate the expression of antioxidant phase II detoxification enzymes HO-1 and GCLC, and then reduce oxidative damage.     

Coordination compounds of some 3d metals with 3-methyl-1-phenyl-4-formylpyrazol-5-one

CuL₂ · 1.5H₂O and ML₂ · 2H₂O · 2EtOH (M = Co²⁺, Ni²⁺, Mn²⁺) coordination compounds were synthesized via the exchange reaction between the sodium salt of 3-methyl-1-phenyl-4-formylpyrazol-5-one (HL) and metal chlorides.The synthesized compounds were studied by thermogravimetry, magnetochemistry, and electron and IR spectroscopy. The complexes CuL₂ · 2Py and CoL₂ · 2Py · MeOH were obtained via recrystallization from a methanol-pyridine mixture, and their structures were studied by X-ray diffraction. Pyrazolone was found to be coordinated in the deprotonated enol form and to form six-membered chelate rings with a metal. The coordination polyhedron of a metal cation was found to be a square bipyramid (Cu²⁺) or an axially elongated octahedron (Co²⁺) with its vertices occupied by the oxygen atoms of 3-methyl-1-phenyl-4-formylpyrazol-5-one and the nitrogen atoms of pyridine.