Complexes of cobalt(II) halides with 2-(1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)-4(3<Emphasis Type="Italic">H</Emphasis>)-pyrimidinone

The electronic structures of complexes of cobalt(II) halides with 2-(1H-pyrazol-1-yl)-4(3H)-pyrimidinone have been studied by X-ray photoelectron spectroscopy. The Co2p _3/2 lines of cobalt atoms, N1s lines of nitrogen atoms, and O1s lines of oxygen atoms in the X-ray photoelectron spectra have been analyzed. Based on these data for the free and coordinated ligands, the atoms of the ligand coordinated to the central metal atom are determined. The coordinated organic compound serves as an electron-donating ligand. The results obtained are consistent with IR and UV-Vis spectroscopic data.     

Synthesis and structure of (bis(3,5-dimethyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)methane)diiodocobalt(II)

A cobalt(II) iodide complex with bis(3,5-dimethyl-1H-pyrazol-1-yl)methane (L) CoLI₂ has been synthesized, and its single crystals have been obtained. The complex compound was characterized by electron spectroscopy and X-ray diffraction analysis. The compound crystallizes in the monoclinic system (a = 8.4044(4) Å, b = 13.3120(5) Å, c = 14.5824(7) Å; β = 94.7290(10)°; V = 1625.92(13) ų; Z = 4; ρ^calc = 2.112 g/cm³; space group P2₁/m). The structure of the complex is molecular mononuclear. L is a cyclic bidentate ligand; the coordination polyhedron of cobalt is a CoN₂I₂ tetrahedron formed by the nitrogen atoms of the pyrazole fragments L and iodine atoms. The complex has π-π stacking interactions between the pyrazole rings of CoLI₂ molecules, binding the molecules into infinite chains along the b axis.     

Aqueous hydrolysis of 3-[2-(3-methyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)-ethylamino]-and 3-[2-(5-methyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)ethylamino]-propanoates

Noncatalytic hydrolysis of methyl 3-[2-(3-methyl-1H-pyrazol-1-y)ethylamino]-and methyl 3-[2-(5-methyl-1H-pyrazol-1-yl)ethylamino]propanoates at 200°C was performed. According to X-ray diffraction data, the resulting acids exist exclusively as salts.     

Synthesis,structures and magnetic properties of three copper(II) complexes of 2-(1<Emphasis Type="Italic">H</Emphasis>-pyrazol-3-yl) pyridine

Three Cu(II) complexes: [Cu₂(μ-L)₂(HCOO)₂(H₂O)₂] (1), [Cu₂(μ-L)₂(NO₃)₂] (2), and [Cu₄(μ-L)₆(CH₃COO)₂]·2H₂O (3) constructed from 2-(1H-pyrazol-3-yl) pyridine (HL) were synthesized and structurally characterized by X-ray single-crystal diffraction. The X-ray analyses revealed that all three complexes feature a di-ligand-bridged Cu₂ unit, which is nearly planar. Each deprotonated ligand chelates one copper atom by means of N,N(pyridine-pyrazole) pocket and simultaneously bridges the other one by the N,N(pyrazole) groups. The remaining coordination sites of the Cu(II) centers are either occupied by different anionic coligands to balance the charge, or bridged by another L to develop a tetranuclear structure. Magnetic investigations reveal that the distortion of the Cu(II) coordination geometry (as described by the τ values) and the coplanarity of the Cu–(N=N)₂–Cu unit have cooperative effects on the antiferromagnetic strength of these systems.     

3-(4,5-Dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-ylmethyl)oxazolidines and 3-(4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-ylmethyl)perhydro-1,3-oxazines

3-(4,5-Dihydro-1H-pyrazol-1-ylmethyl)oxazolidines and 3-(4,5-dihydro-1H-pyrazol-1-ylmethyl)perhydro-1,3-oxazines were synthesized in 54–85% yield by reactions of α-amino alcohols and 3-aminopropan-1-ol, respectively, with formaldehyde and 4,5-dihydro-1H-pyrazoles.     

Three ways of reactions of 5-(3,5-dimethyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)-2-phenyl-1,3-oxazole-4-carbonitrile and its analogs with nitrogen-containing bases

Substituted 5-(3,5-dimethyl-1H-pyrazol-1-yl)-1,3-oxazole-4-carbonitrile differently react with nitrogen bases having different numbers of labile hydrogen atoms. Treatment of the title compounds with secondary amines or morpholine results in nucleophilic replacement of the pyrazolyl substituent at C⁵, the ozaxole ring remaining unchanged. Their reactions with primary amines are accompanied by cleavage of the oxazole ring with formation of the corresponding enamino nitriles. Hydrazine hydrate acts in a similar way, but enehydrazino nitriles thus formed undergo fast cyclization to give new 4,5-diaminopyrazole derivatives. The latter can be converted into substituted pyrazolo[1,5-a]pyrimidines whose structure has been proved by X-ray analysis.     

Regioselective synthesis of polyfluoroalkyl-substituted 7-(1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-1-yl)-6,7-dihydro-1<Emphasis Type="Italic">H</Emphasis>-indazol-4(5<Emphasis Type="Italic">H</Emphasis>)-ones

3-Polyfluoroalkyl-6,6-dimethyl-7-(1H-1,2,3-triazol-1-yl)-6,7-dihydro-1H-indazol-4(5H)-ones were synthesized with high regioselectivity by 1,3-dipolar cycloaddition of terminal alkynes (phenylacetylene, hex- 1-yne, hept-1-yne, and but-3-yn-1-ol) to 7-azido-6,6-dimethyl-3-polyfluoroalkyl-6,7-dihydro-1H-indazol-4(5H)-ones which were prepared by bromination of 6,6-dimethyl-3-polyfluoroalkyl-6,7-dihydro-1H-indazol- 4(5H)-ones with N-bromosuccinimide in anhydrous carbon tetrachloride, followed by treatment of the corresponding 7-bromo derivatives with sodium azide.     

Synthesis of ditopic ligands containing bis(1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)-methane fragments

New approaches have been proposed for the synthesis of compounds containing two bis(1H-pyrazol-1-yl)methane fragments. Nucleophilic replacement of the halogen atoms in appropriate tetrabromo derivatives by pyrazoles in the superbasic system KOH-DMSO gave ditopic chelating ligands: 1,1,2,2-tetrakis(1H-pyrazol-1-yl)ethane, 1,4-bis[bis(1H-pyrazol-1-yl)methyl]benzene, and 1,4-bis[bis(3,5-dimethyl-1H-pyrazol-1-yl)methyl]benzene. 1,4-Bis[bis(1H-pyrazol-1-yl)methyl]benzene was also synthesized by reaction of 1H-pyrazole with terephthalaldehyde in the presence of thionyl chloride. 1,1,2,2-Tetrakis(1H-pyrazol-1-yl)ethane was converted into the corresponding tetraiodo and tetranitro derivatives.     

Synthesis and Aggregation of Cationic Zinc and Magnesium Phthalocyanines Containing 4-(3,5-Dimethyl-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-yl)phenoxy Groups

Tetracationic metal phthalocyanines were synthesized by the quaternization of the C_s-regioisomers of tetrasubstituted zinc and magnesium phthalocyanines containing 3,5-dimethylpyrazole fragments. The individuality of the synthesized compounds was confirmed by HPLC?mass spectrometry. The aggregation of the cationic metal phthalocyanines in water and aqueous-organic media, as well as in the presence of Triton X- 100 was studied. The dependence of the dimerization constant on the polarity of mixed solvents was determined.     

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.     

Electrophilic cyclization of <Emphasis Type="Italic">N</Emphasis>-allyl(propargyl)-5-amino-1<Emphasis Type="Italic">H</Emphasis>-pyrazole-4-carboxamides. Synthesis of 4-[(dihydro)oxazol-2-yl]-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-5-amines

N-Allyl-5-amino-1H-pyrazole-4-carboxamides in reactions with polyphosphoric acid, with N-halosuccinimides in chloroform, and with (chlorosulfanyl)benzenes in nitromethane in the presence of lithium perchlorate underwent cyclization involving the N-allylamide fragment to give 4-[5-methyl(halomethyl)-4,5-dihydrooxazol-2-yl]-1H-pyrazol-5-amines and 2-(5-amino-1H-pyrazol-4-yl)-5-[(arylsulfanyl)methyl]-4,5-dihydro-1,3-oxazolium perchlorates, respectively. Analogous reactions of N-propargyl-5-amino-1H-pyrazole-4-carboxamides with polyphosphoric acid afforded 4-(5-methyloxazol-2-yl)-1H-pyrazol-5-amines, and with (chlorosulfanyl) benzenes, 2-(5-amino-1H-pyrazol-4-yl)-5-[(arylsulfanyl)methylidene]-4,5-dihydro-1,3-oxazolium perchlorates.     

Fusion of 2-(furan-2-yl)thiazole to 1-methyl-1<Emphasis Type="Italic">H</Emphasis>-benzimidazole

Methylation of 5(6)-nitro-1H-benzimidazole with methyl iodide in the presence of potassium hydroxide and N-methylpyrrolidin-2-one gave a mixture of isomeric 1-methyl-5-nitro- and 1-methyl-6-nitro-1H-benzimidazoles which were reduced with tin in concentrated aqueous HCl on heating. The resulting amines reacted with furan-2-carbonyl chloride in N-methylpyrrolidin-2-one to give furan-2-carboxamides which were treated with excess P₂S₅ in pyridine. Oxidation of isomeric furan-2-carbothioamides with K₃[Fe(CN)₆] in alkaline medium afforded a mixture of intramolecular cyclization products, 2-(furan-2-yl)-6-methyl-6H-imidazo[4,5-g][1,3]benzothiazole and 2-(furan-2-yl)-8-methyl-8H-imidazo[4,5-g][1,3]benzothiazole which were separated by column chromatography and identified.     

Microwave assisted synthesis of substituted (<Emphasis Type="Italic">Z</Emphasis>)-2-{[1-phenyl-3-(thiophen-2-yl)-1<Emphasis Type="Italic">H</Emphasis>-pyrazol- 4-yl]methylene}benzofuran-3(2<Emphasis Type="Italic">H</Emphasis>)-ones and their antimicrobial activity

Aurones, pyrazole and thiophene scaffolds are known for their potential antimicrobial activity. Herein, we have synthesized hybrid compounds containing three substituted (Z)-2-{[1-phenyl-3-(thiophen-2-yl)- 1H-pyrazol-4-yl]methylene}benzofuran-3(2H)-ones that had been produced from substituted (E)-1-(2-hydroxyphenyl)- 3-[1-phenyl-3-(thiophen-2-yl)-1H-pyrazol-4-yl]prop-2-en-1-ones in high yields. All synthesized compounds were tested in vitro for their antimicrobial activity. Several of those demonstrated promising activity against some fungal and bacterial strains.     

Synthesis and crystal structure of (1<Emphasis Type="Italic">H</Emphasis>-Benzo[<Emphasis Type="Italic">d</Emphasis>]imidazol-2-yl)(3,3-dimethyl-3,4-dihydroisoquinolin-1-yl)methanone (L). complex formation of copper(II) and cobalt(II) chlorides with L

(1H-Benzo[d]imidazol-2-yl)(3,3-dimethyl-3,4-dihydroisoquinolin-1-yl)methanone (L) and its complexes with copper and cobalt chlorides [CuLCl₂] (I) and [CoLCl₂] (II) are synthesized and studied by IR spectroscopy. The structure of molecule L is determined by X-ray diffraction analysis. Molecule L crystallizes as a cis-trans isomer. The dihydroisoquinoline (A) and benzimidazole (B) fragments lie in the mutually perpendicular planes. The N-C bond lengths of fragment A (double bond N(1)-C(1) 1.278(3) Å, ordinary bond N(1)-C(9) 1.490(3) Å) differ noticeably. The N-C bond lengths in fragment B range from 1.327(4) to 1.389(4) Å. The C=O bond is 1.218(3) Å According to the data of IR spectroscopy and X-ray diffraction analysis, complexes I and II are assumed to have different structures with different coordination modes to the metal atom of molecule L: through the imine atoms N(1) and N(2) of fragments A and B in I and through the N(1) atom of the dihydroisoquinoline fragment and the O atom of the carbonyl group in II.     

Synthesis and some transformations of 1-methyl-2-(thiophen-3-yl)-1<Emphasis Type="Italic">H</Emphasis>-benzimidazole

1-Methyl-2-(thiophen-3-yl)-1H-benzimidazole was synthesized by the Weidenhagen reaction, followed by N-methylation. Electrophilic substitution reactions of the title compound, in particular nitration, bromination, sulfonation, formylation, and acylation, were studied. The formylation and acylation in polyphosphoric acid afforded mixtures of 2- and 5-substituted isomers at the thiophene ring. The nitration of 1-methyl-2-(thiophen-3-yl)-1H-benzimidazole involved the thiophene ring or both thiophene and benzene fragments, depending on the conditions. Steric arrangement of the heterocycles in the 1-methyl-2-(thiophen-3-yl)-1H-benzimidazole molecule was analyzed by quantum chemical calculations.     

Reaction of ethyl 4-[(<Emphasis Type="Italic">E</Emphasis>)-1-chloro-3-oxoprop-1-en-1-yl]-3,5-dimethyl-1<Emphasis Type="Italic">H</Emphasis>-pyrrole-2-carboxylate with hydrazines

Ethyl 4-[(E)-1-chloro-3-oxoprop-1-en-1-yl]-3,5-dimethyl-1H-pyrrole-2-carboxylate reacted with substituted hydrazines in different solvents to give mixtures of regioisomeric 3- and 5-substituted pyrazoles. Conditions were found for selective formation of 1-aryl(alkyl)-5-(5-ethoxycarbonyl-2,4-dimethyl-1H-pyrrol-3-yl)-1H-pyrazoles.     

Crystal structure of 9-(5,5-dimethyl-2,4,5,6-tetrahydro-1<Emphasis Type="Italic">H</Emphasis>-phenalen-2-yl)-5,5,9-trimethyl-5,6,8,9-tetrahydrocyclopenta[<Emphasis Type="Italic">a</Emphasis>]phenalen-10(4<Emphasis Type="Italic">H</Emphasis>)-one

The structure of 9-(5,5-dimethyl-2,4,5,6-tetrahydro-1H-phenalen-2-yl)-5,5,9-trimethyl-5,6,8,9-tetrahydrocyclopenta[а]phenalen-10(4H)-one was determined by X-ray crystallography. The intermolecular interaction energies were calculated by the atom-atomic approach for the crystal structure. The character of the crystal structure and the structural subclass were established.     

Regioselectivity in the reactions of <Emphasis Type="Italic">N</Emphasis>-(polychloroethylidene)-sulfonamides with 1<Emphasis Type="Italic">H</Emphasis>-pyrrole and 1-methyl-1<Emphasis Type="Italic">H</Emphasis>-pyrrole

N-(2,2,2-Trichloroethylidene)arenesulfonamides react with 1H-pyrrole and 1-methyl-1H-pyrrole to give the corresponding N-[2,2,2-trichloro-1-(1H-pyrrol-2-yl)ethyl]arenesulfonamides. The reaction of N-(2,2,2-trichloroethylidene)trifluoromethanesulfonamide with pyrrole leads to a mixture of 2-mono-and 2,5-disubstituted pyrroles, whereas in the reaction with 1-methyl-1H-pyrrole only the 2-substituted compound is formed. N-(2,2-Dichloro-2-phenylethylidene)-4-methylbenzenesulfonamide reacts with 1H-pyrrole to form N-[2,2-dichloro-2-phenyl-1-(1H-pyrrol-2-yl)ethyl]-4-methylbenzenesulfonamide, and its reaction with 1-methyl-1H-pyrrole gives a mixture of 2-and 3-monosubstituted derivatives. The results of quantum-chemical calculations of the initial reactants and products indicate that the process is orbital-controlled. A good agreement is observed between the experimental data and theoretical conclusions concerning the dependence of the reaction regioselectivity on the nature of substituents in the electrophile molecule.