<Emphasis Type="Italic">N</Emphasis>-acylimino-substituted 2-oxa-7-azaspiro[4.4]nona-3,6,8-trienes in the synthesis of 3-(1<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazol-3-yl)-3<Emphasis Type="Italic">H</Emphasis>-pyrrole-4-carbonitriles

Reaction with phenylhydrazine of 3Н-pyrroles spirobound to a furan ring, N-acylimino-substituted 2-oxa-7-azaspiro[4.4]nona-3,6,8-trienes, occurs with a diasteroselective formation of previously unknown derivatives of 1,2,4-triazole: 5-amino-3-(5-alkyl-1-phenyl-1H-1,2,4-triazol-3-yl)-2-morpholin-4-yl-3H-pyrrole-4-carbonitriles.     

Synthesis of heterocycles based on arylation products of unsaturated compounds: XVII. Arylation of 2-acetylfuran and synthesis of 3-R-6-(5-aryl-2-furyl)-7<Emphasis Type="Italic">H</Emphasis>-[1,2,4]triazolo[3,4-<Emphasis Type="Italic">b</Emphasis>][1,3,4]thiadiazines

Reaction of 2-acetylfuran with arenediazonium chlorides under Meerwein reaction conditions led to the formation of 5-aryl-2-acetylfurans. The bromination of these compounds gave 2-bromo-1-(5-aryl-2-furyl)-ethanones that reacted with 4-amino-4H-5-R-1,2,4-triazole-3-thiols to form 3-R-6-(5-aryl-2-furyl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines.     

Synthesis and reactions of 3-(3-ethoxycarbonyl-1-phenyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-4-yl)propenic acid

The reaction of ethyl 4-formyl-1-phenyl-1H-pyrazole-3-carboxylate with the malonic acid led to the formation (2E)-3-(3-ethoxycarbonyl-1-phenyl-1H-pyrazol-4-yl)propenic acid. In reactions of this acid chloride with 4-amino-5-aryl(hetaryl)-4H-1,2,4-triazole-3-thiols were obtained ethyl 4-[(E)-2-{3-aryl(hetaryl)[1,2,4]triazolo[3,4-b][1,3,4]thiadiazol-6-yl}ethenyl]-1-phenyl-1H-pyrazoe-3-carboxylates, with 5-aryltetrazoles, ethyl 4-[(E)-2-(5-aryl-1,3,4-oxadiazol-2-yl)-ethenyl]-1-phenyl-1H-pyrazole-3-carboxylates, with 1-(2-hydroxy-3,5-dimethylphenyl) followed by the Baker-Venkataraman rearrangement and the cyclization, ethyl 4-[(E)-2-(6,8-dimethyl-4-oxo-4Hchromen-2-yl)ethenyl]-1-phenyl-1H-pyrazole-3-carboxylate.     

Tautomerism of aza cycles: II. Synthesis and structure of 5-substituted 3-(2-hydroxyethylsulfanyl)-1<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazoles and their salts. Preference of the 1H,4<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazolium tautomers

New complexing agents, potentially tautomeric 3-(2-hydroxyethylsulfanyl)-1H-1,2,4-triazole, its 5-methyl-and 5-phenyl-substituted analogs, and some their salts, were synthesized, and their structure was discussed on the basis of the ¹H and ¹³C NMR, IR, and mass spectra, X-ray diffraction data, and published data. In keeping with the rule formulated previously for N-unsubstituted 1,2,4-triazoles having dissimilar substituents, the synthesized compounds were found to exist as 3-(2-hydroxyethylsulfanyl)-5-R-1H-1,2,4-triazole tautomers (3-R_A-5-R_D-1H-1,2,4-triazoly). They are protonated at the nitrogen atom in position 4 of the triazole ring. The ¹H and ¹³C NMR spectra of these compounds in trifluoroacetic acid suggest the presence of two forms due to equilibrium between the neutral and protonated species. Analysis of the crystallographic data for the triazolium salts and published data showed preference of the 1H,4H-1,2,4-triazolium tautomer.     

Synthesis of 3-(2-hydroxyphenyl)-1,5-dialkyl-1<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazoles and their Zn(II) complexes

It has been demonstrated by ¹³C NMR and quantum-chemical calculations that alkylation of 5-(2-hydroxyphenyl)-3-methyl(vinylphenyl)-1H-1,2,4-triazoles with dialkyl sulfates in aqueous DMSO in the presence of alkali occurs exclusively in the 2-position of the triazole ring to give 3-(2-hydroxyphenyl)-1,5-dialkyl(alkylvinylphenyl)-1H-1,2,4-triazoles. Emission spectra of these compounds show two weak bands (λ _max ^fl = 317–346 and 430–447 nm, φ = 0.002–0.007), whereas their zinc complexes emit in the violet range of the visible spectrum (λ _max ^fl = 373–377 nm, φ = 0.20–0.25).     

Oxorhenium(V) complexes with bidentate carbohydrazide Schiff bases: synthesis,characterization and DNA interaction studies

The respective coordination reactions of trans-[ReOCl₃(PPh₃)₂] with N-[(4-oxo-4H-chromen-3-yl)methylidene]thiophene-2-carbohydrazide (Hchrtc) and N-[1,3-benzothiazol-2-ylmethylidene]thiophene-2-carbohydrazide (Hbztc) afforded two novel oxorhenium(V) complexes, cis-[ReOCl₂(chrtc)(PPh₃)] (1) and cis-[ReOCl₂(bztc)(PPh₃)] (2). These metal compounds were elucidated spectroscopically and their solid-state structures determined by single-crystal X-ray diffraction. The redox properties of the metal complexes were probed using cyclic and square wave voltammetry. The DNA interaction capabilities of 1 and 2 were gauged via UV/Vis spectroscopy DNA titrations and gel electrophoresis studies. A correlation is identified between the DNA cleavage observations and the redox potentials of the metal complexes.     

Fragmentation of Protonated <Emphasis Type="Italic">N</Emphasis>-(3-Aminophenyl)Benzamide and Its Derivatives in Gas Phase

An ion of m/z 110.06036 (ion formula [C₆H₈NO]⁺; error: 0.32 mDa) was observed in the collision induced dissociation tandem mass spectrometry experiments of protonated N-(3-aminophenyl)benzamide, which is a rearrangement product ion purportedly through nitrogen-oxygen (N–O) exchange. The N–O exchange rearrangement was confirmed by the MS/MS spectrum of protonated N-(3-aminophenyl)-O ¹⁸ -benzamide, where the rearranged ion, [C₆H₈NO ¹⁸ ]⁺ of m/z 112 was available because of the presence of O ¹⁸ . Theoretical calculations using Density Functional Theory (DFT) at B3LYP/6-31 g(d) level suggest that an ion-neutral complex containing a water molecule and a nitrilium ion was formed via a transition state (TS-1), followed by the water molecule migrating to the anilide ring, eventually leading to the formation of the rearranged ion of m/z 110. The rearrangement can be generalized to other protonated amide compounds with electron-donating groups at the meta position, such as, –OH, –CH₃, –OCH_3, –NH(CH₃)₂, –NH-Ph, and –NHCOCH₃, all of which show the corresponding rearranged ions in MS/MS spectra. However, the protonated amide compounds containing electron-withdrawing groups, including –Cl, –Br, –CN, –NO₂, and –CF₃, at the meta position did not display this type of rearrangement during dissociation. Additionally, effects of various acyl groups on the rearrangement were investigated. It was found that the rearrangement can be enhanced by substitution on the ring of the benzoyl with electron-withdrawing groups.

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Low-temperature equilibriums in solutions of isocyanide-phosphine complexes of palladium(II) chloride

cis-[PdCl₂(CNR)(PPh₃)] [R = Cy, t-Bu, C(Me)₂CH₂C(Me)₃] have been synthesized via the interaction of [(PPh₃)ClPd(μ-Cl)₂PdCl(PPh₃)] with isocyanide in CH₂Cl₂ at room temperature with 90–98% yield and characterized by means of mass spectrometry as well as ¹H, ¹³C{¹H, ³¹P}, and ³¹P{¹H} NMR spectroscopy. The complexes structure in the solid phase has been elucidated by means of X-ray diffraction analysis. Dynamic processes in the solutions of the complexes in CDCl₃ and CD₂Cl₂ at temperature of–95 to 60°С have been studied by means of ¹H and ³¹P NMR spectroscopy. It has been found that the studied compounds existed exclusively in the cis-[PdCl₂(CNR)(PPh₃)] form in the solutions. In the case of cis-[PdCl₂(CNCy)(PPh₃)] in CH₂Cl₂, the conformational transitions of the equilibrium forms (the transition of the substituent in the cyclohexyl cycle between the equatorial and axial positions) are slowed down, the equatorial conformer prevailing in the solution (2: 1 at–95°С). Quantum-chemical simulation (DFT) has revealed that the standard Gibbs energy of the conformational transition from the axial form of cis-[PdCl₂(CNCy)(PPh₃)] into the equatorial one in the CH₂Cl₂ solution at 178 K equals–2.5 kJ/mol, being in agreement with the experimental data.     

Synthesis and antimicrobial activity of novel fused [1,2,4]triazino[5,6-<Emphasis Type="Italic">b</Emphasis>]indole derivatives

Synthesis of new fused systems of triazino[5,6-b]indole starting with preparation of 3-amino[1,2,4]-triazino[5,6-b]indole 1 by reaction of isatin with 2-aminoguanidinium carbonate in boiling acetic acid is presented [1]. Intermediate compound 1 reacted with aldehyde, ethyl chloroformate, triethyl orthoformate, and ninhydrine and gave new heterotetracyclic nitrogen systems, such as 3-(N ²-guanidinylimino)indole-2(1H)-one 2, 3-(N-ethoxycarbonylamino)-4H-[1,2,4]triazino[5,6-b]indole 3, 3-(N-ethoxymethyleneamino)-4H-[1,2,4]-triazino[5,6-b]indole 4, 3-(hydrazinothiocarbonylamino)-4H-[1,2,4]triazino[5,6-b]indole 5, respectively. N-(1,3-dioxoindene-2-ylidene)-4H-[1,2,4]triazino[5,6-b]indol-3-amine 6 was synthesized by reaction of compound 1 with aldehyde, ethyl chloroformate, triethyl orthoformate, and ninhydrine. New fused indole systems, pyrimido[2′,1′:3,4][1,2,4]triazino[5,6-b]indol-3(4H)-one 8, 9, 11, 12 and 1H-imidazo[2′,1′:3,4][1,2,4]triazino-[5,6-b]indol-2(3H)-one 10, were synthesized in the reaction of the intermediate 1 with bifunctional compounds. Structures of the products were elucidated from their elemental analysis and spectral data (IR, ¹H and ¹³C NMR and mass spectra). Antimicrobial activity of some synthesized compounds was tested.     

Syntheses and characterisation of chloro(h3-allyl) dicarbonylmolybdenum(II) complexes of chiral and achiral ditertiaryphosphines

A series of the complexes of the general formula [ClMo(CO)₂(η ³-C₃H₅)(P-P)], [where (P-P) = (m-CH₃C₆H₄)₂P(CH₂)₂PPh₂ (m-t-dppe); cis-Ph₂PCH=CHPPh₂ (cis-diphos); Ph₂PCH₂CH₂AsPh₂ (arsaphos); Ph₂P(CH₂)₄PPh₂ (dppb); (±)-1,2-C₆H₄(PMePh)₂ (rac-diphos); (2R,3R)Ph₂PC*H(Me)C*H(Me)PPh₂ (+)-chiraphos; (R,R)-Me₂C(O)₂{C*HCH₂PPh₂}₂ (-)-diop] were synthesised by the reaction of the precursor complex [ClMo(CO)₂(η ³-C₃H₅)(CH₃CN)₂] with the corresponding ditertiary phosphine in acetone. The complexes were isolated as yellow to orange air-stable solids and characterised by elemental analyses, FTIR and multinuclear NMR [¹H, ³¹P{¹H}] spectroscopic techniques. The carbonyl force constant values were calculated by Cotton and Kraihanzel approximate secular equations using ν _C≡O stretching frequencies observed in the FTIR and these were found to be 14.30–14.59 mdyne 0-A^?1 and 0.23–0.70 mdyne Å^?1 for K₁ and K_i respectively. Spectroscopic evidences have confirmed cis-octahedral structures for the synthesized complexes.     

Synthesis of 1,2,4- and 1,3,4-oxadiazoles from 1-aryl-5-methyl-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazole-4-carbonyl chlorides

5-Substituted 2-(1-aryl-5-methyl-1H-1,2,3-triazol-4-yl)-1,3,4-oxadiazoles were synthesized by reaction of 1-aryl-5-methyl-1H-1,2,3-triazole-4-carbonyl chlorides with the corresponding 5-substituted 1H-tetrazoles. 5-Methyl-1-phenyl-1H-1,2,3-triazole-4-carbonyl chloride reacted with N′-hydroxybenzimidamides to give 3-aryl-5-(5-methyl-1-phenyl-1H-1,2,3-triazol-4-yl)-1,2,4-oxadiazoles. Reactions of 4-(5-methyl-1H-1,2,3-triazol-1-yl)benzoic acid with N′-hydroxybenzimidamides resulted in the formation of 3-aryl-5-[4-(5-methyl-1H-1,2,3-triazol-1-yl)phenyl]-1,2,4-oxadiazoles.     

Catalytic multimolecular reactions of 1,3-dicarbonyl CH acids with CH<Subscript>2</Subscript>O and <Emphasis Type="Italic">S</Emphasis>- and <Emphasis Type="Italic">N</Emphasis>-nucleophiles

The literature data on the synthesis and properties of oxo-functionalized acyclic and cyclic sulfides obtained by the catalytic multicomponent reactions of 1,3-dicarbonyl compounds with formaldehyde and S-nucleophiles are summarized. An approach to the multimolecular four-component heterocyclization of 1,3-dicarbonyl compounds with CH₂O and S- and N-nucleophiles in the synthesis of sulfanyl-substituted azaheterocycles is discussed.     

Mass spectra of new heterocycles: XV. Fragmentation of 1-substituted 3-alkoxy-2-(propargylsulfanyl)- and 3-alkoxy-2-(allenylsulfanyl)-1<Emphasis Type="Italic">H</Emphasis>-pyrroles under electron impact

The electron impact mass spectra of 1-R-substituted 3-alkoxy-2-(propargylsulfanyl)- and 3-alkoxy-2-(allenylsulfanyl)-1H-pyrroles (R = Me, i-Pr, s-Bu, Ph) have been studied for the first time. These compounds give rise to stable molecular ions whose primary fragmentation follows three competing pathways: cleavage of the C–O bonds with expulsion of alkyl radical, cleavage of the C–S bonds with formation of [M–C₃H₃]⁺ ions, and cleavage of the C–N bonds with synchronous hydrogen transfer to give odd-electron [M–C_nH_2n]+ · ion. The main fragmentation pathway of 2-(propargylsulfanyl) derivatives is cleavage of the C–S bond with formation of [M–C₃H₃]⁺ ion.     

Synthesis,structure and electrochemical properties of some thiosemicarbazone complexes of iridium

Reaction of thiosemicarbazones of salicylaldehyde and 2-hydroxyacetophenone (H₂L¹ and H₂L²) with [Ir(PPh₃)₃Cl] affords complexes of type [Ir(PPh₃)₂(L)(H)] (L = L¹ or L²) in ethanol. A similar reaction carried out in toluene affords the [Ir(PPh₃)₂(L)(H)] complexes along with complexes of type [Ir(PPh₃)₂(L)Cl], where a chloride is coordinated to iridium instead of the hydride. The structure of the [Ir(PPh₃)₂(L²)(H)] and [Ir(PPh₃)₂(L²)Cl] complexes has been determined by X-ray crystallography. Crystal data for [Ir(PPh₃)₂(L²)(H)]: space group, P2₁/c; crystal system, monoclinic; a=12.110(2) Å, b=17.983(4) Å, c=18.437(4) Å, β=103.42(3)°, Z=4; R ₁=0.0591, wR ₂=0.1107. Crystal data for [Ir(PPh₃)₂(L²)Cl]: space group, P2₁/c; crystal system, monoclinic; a=17.9374(11) Å, b=19.2570(10) Å, c=24.9135(16) Å, β=108.145(5)°, Z=4; R ₁=0.0463, wR ₂=0.0901. In all the complexes the thiosemicarbazones are coordinated to the metal center as dianionic tridentate O, N, S-donors and the two triphenylphosphines are trans. The complexes are diamagnetic (low-spin d? ⁶, S=0) and show intense MLCT transitions in the visible region. Cyclic voltammetry on all the [Ir(PPh₃)₂(L)(H)] and [Ir(PPh₃)₂(L)Cl] complexes shows a quasi-reversible Ir(III)–Ir(IV) oxidation within 0.55–0.78 V vs. SCE followed by an irreversible oxidation of the thiosemicarbazone within 0.91–1.27 V vs. SCE. An irreversible reduction of the thiosemicarbazone is also observed within ?1.10 to ?1.23 V vs. SCE.     

Crystal structure of <Emphasis Type="Italic">tris</Emphasis>-(dipivaloylmethanato) (ethylendiamine)yttrium(III)

The structure of a mixed-ligand complex tris-(dipivaloylmethanato)(ethylendiamine)yttrium(III) [Y(en)(dpm)₃] is studied at 150(2) K by single crystal XRD. The crystallographic data for C₃₅H₆₅N₂O₆Y are as follows: space group P2₁/c, a = 10.3771(3) Å, b = 26.3566(8) Å, c = 14.8412(4) Å, β = 100.385(2)°, V = 3992.6(2) ų, Z = 4. The structure is molecular. The coordination environment of yttrium atoms is square antiprismatic; the Y–О distances are 2.2597(13)-2.3760(12) Å and Y–N distances are 2.5381(16) Å and 2.5499(17) Å.     

Reaction of Imidazoles and Triazoles with 1-(Benzotriazol-1-yl)-2-iodoethanone

Reactions of 2-methyl-1H-imidazole, 1H-benzimidazole, 4H-1,2,4-triazole, and 1H-benzotriazole with 1-(1H-benzotriazol-1-yl)-2-iodoethan-1-one in the absence of a base gave the corresponding N-mono- and N,N′-disubstituted derivatives. 4H-1,2,4-Triazole-3-thiol reacted with 1-(1H-benzotriazol-1-yl)-2-iodoethan-1- one to afford 1-([1,3]thiazolo[2,3-c][1,2,4]triazol-5-yl)-1H-benzotriazolium triiodide.     

Synthesis and Biological Activity of 3,4-Diaryl-5-[4-(acetylsulfamoyl)phenyl]-4,5-dihydropyrrolo[3,4-<Emphasis Type="Italic">c</Emphasis>]pyrazol-6(2<Emphasis Type="Italic">H</Emphasis>)-ones and Their Sodium Salts

3,4-Diaryl-5-[4-(acetylsulfamoyl)phenyl]-4,5-dihydropyrrolo[3,4-c]pyrazol-6(2H)-ones were synthesized be reaction of 5-aryl-4-aroyl-1-[4-(acetylsulfamoyl)phenyl]-3-hydroxy-1H-pyrrole-2(5H)-ones with hydrazine hydrate in glacial acetic acid, and their sodium salts were obtained by treatment with sodium methoxide in methanol–DMF (1: 1). Analgesic and anti-inflammatory activity and acute toxicity of the synthesized compounds were studied.     

Quantum-chemical study of donor-acceptor interactions in rhodium(I) carbonyl carboxylate complexes with phosphine ligands

The DFT B3LYP method was used to optimize the geometries, calculate the IR spectra, and analyze the electronic structures of carbonyl(carboxylato)(phosphine)rhodium(I) complexes, namely, trans-[Rh(Cl)(CO)(PPh₃)₂], trans-[Rh(OCOR)(CO)(PPh₃)₂] (R = H, CH₃, and CF₃), and trans-[Rh(OCOH)(CO)(PX₃)₂], and free PX₃ molecules (X = H, F, CH₃, i-Pr, Cy, and Ph). A linear correlation between v(CO) in the IR spectra of trans-[Rh(OCOH)(CO)(PX₃)₂] and the HOMO energy of the free PX₃ molecule was found for phosphines with nonaromatic substituents X. It was concluded that the electronic state of the CO group is mainly determined by the σ-donor properties of phosphines. The distinctive features of the electronic structure of triphenylphosphine are discussed.     

Synthesis and properties of cyanomethyl derivatives of imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyridine,imidazo[1,2-<Emphasis Type="Italic">a</Emphasis>]pyrimidine,and imidazo[2,1-<Emphasis Type="Italic">b</Emphasis>]thiazole

2-Cyanomethyl derivatives were obtained of imidazo[1,2-a]pyridine, imidazo[1,2-a]pyrimidine, and imidazo[2,1-b]thiazole, and their reactivity was investigated by an example of imidazo[1,2-a]pyridine: It was subjected to nitration, bromination, azo coupling and nitrosation. Acylation of the methylene group effected by amino acids esters with a subsequent addition of the amino group to the cyano group resulted in the formation of 5-amino-4-imidazo[1,2-a]-pyridin-2-yl-1-phenyl-1,2-dihydro-3H-pyrrol-3-one and 2-amino-1-ethyl-3-imidazol[1,2-a]pyridin-2-yl-4(1H)-quinolinone.     

Synthesis,structure, physicochemical properties,and solid-phase thermolysis of Co<Subscript>2</Subscript>Sm(Piv)<Subscript>7</Subscript>(2,4-Lut)<Subscript>2</Subscript>

Heterometallic pivalate Co₂Sm(Piv)₇(2,4-Lut)₂ (1) was prepared for the first time and structurally characterized at 293 and 160 K. Antiferromagnetic exchange interactions are dominant in complex 1. This compound experiences a first-order phase transition within 210–260 K. A set of thermodynamic functions was obtained for this complex (C _p , H _T ⁰ - H ₁₈₀ ⁰ , and S _T ⁰ ), and parameters were determined for solid-phase thermolysis where samarium cobaltate SmCoO₃ is the only product.