Zn(II) and Cu(II) complexes of 2-(2-hydroxy-5-methylphenyl)-1<Emphasis Type="Italic">H</Emphasis>-benzimidazole and crystal structure of 2-(2-hydroxy-5-methylphenyl)-1<Emphasis Type="Italic">H</Emphasis>-benzimidazolium chloride

2-(2-Hydroxy-5-methylphenyl)-1H-benzimidazole ligand (HL) and its complexes with Cu(NO₃)₂, Zn(NO₃)₂ have been synthesized and characterized. The structures of the compounds were confirmed on the basis of elemental analysis, molar conductivity, magnetic moment, FT-IR, ¹H- and ¹³C NMR. Cu(II) complex has 1: 2 metal: ligand ratio, while Zn(II) complex is 1: 1. Crystal structure of 2-(2-hydroxy-5-methylphenyl)-1H-benzimidazolium chloride (HL · HC1) was determined by single-crystal X-ray diffraction. It crystallizes in the orthorombic, space group P2₁2₁2₁and Z = 4.     

Synthesis and reactivity of 4-hydroxy-5-methyl-2-(2-oxo-2<Emphasis Type="Italic">H</Emphasis>-chromen-3-yl)-6<Emphasis Type="Italic">H</Emphasis>-1,3-oxazin-6-ones

4-Hydroxy-6H-1,3-oxazin-6-ones with a coumarin fragment in position 2 of the oxazine ring were synthesized. Their hydrolysis, alcoholysis, and hydrazinolysis afforded a number of new coumarin derivatives containing malonamic acid and 1,2,4-triazole residues. The low stability of the title compounds toward oxygencentered nucleophiles was interpreted by quantum chemical calculations.     

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.     

Study of structure and spectral characteristics of the binuclear zinc complex with (<Emphasis Type="Italic">E</Emphasis>)-2-({2-[3-(pyridin-2-yl)-1<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazol-5-yl]phenylimino}methyl)phenol

A study of the structure and spectral properties of the compound (E)-2-({2-[3-(pyridin-2-yl)-1H-1,2,4-triazol-5-yl]phenylimino}methyl)phenol and its binuclear complex with zinc was carried out by the quantum-chemical calculations at a level of density functional theory. Within the framework of the time-dependent density functional theory were calculated electron spectra of both compounds, which gave good agreement with experiment, and was revealed the nature of the absorption bands in the visible and near UV region taking into account the solvent effect. Complete interpretation of the absorption bands in the infrared spectra of the complex and protonated ligand was given, and the frequency shift and changes in the intensities of IR bands of the ligand at the complex formation were analyzed.     

Features of Reaction of 2-(5-Methyl-2-phenyl-2<Emphasis Type="Italic">H</Emphasis>-1,2,3-diazaphosphol-4-yl)-4<Emphasis Type="Italic">H</Emphasis>-benzo[<Emphasis Type="Italic">e</Emphasis>]-1,3,2-dioxaphosphorin-4-one with 1,2-Dicarbonyl Compounds

2-(5-Methyl-2-phenyl-2H-1,2,3-diazaphosphol-4-yl)-4H-benzo[e]-1,3,2-dioxaphosphorin-4-one reacts with perfluorodiacetyl, 3,6-di(tert-butyl)-1,2-benzoquinone and phenanthrenequinone only with the participation of a three-coordinated phosphorus atom to form spirophosphoranes containing acyclic 5-methyl-2- phenyl-2H-1,2,3-diazaphosphol-4-yl substituent, whereas the interaction with tetrachloro-1,2-benzoquinone proceeds via expanding the six-membered heterocycle to the nine-membered one to form 2-(2-phenyl-2H-1,2,3-diazaphosphol-4-yl)-2,9-dioxo-4,5,6,7-tetrachlorodibenzo[d,h]-1,3,8-trioxaphosphonine.     

Reaction 5-(Arylmethylidene)pyrimidine-2,4,6(1<Emphasis Type="Italic">H</Emphasis>,3<Emphasis Type="Italic">H</Emphasis>,5<Emphasis Type="Italic">H</Emphasis>)-triones with L-Proline and Aldehydes

Boiling in toluene of 5-(arylmethylidene)pyrimidine-2,4,6(1H,3H,5H)-triones with L-proline and aldehyde led to the formation of previously unknown substituted 1′-arylhexahydro-1H-spiro[pyrimidine-5,2′-pyrrolysine]-2,4,6(1H,3Н,5Н)-triones.     

Design,synthesis and biological evaluation of 3-(2-aminooxazol-5-yl)-2<Emphasis Type="Italic">H</Emphasis>-chromen-2-one derivatives

Background

In view of wide range of biological activities of oxazole, a new series of oxazole analogues was synthesized and its chemical structures were confirmed by spectral data (Proton/Carbon-NMR, IR, MS etc.). The synthesized oxazole derivatives were screened for their antimicrobial and antiproliferative activities.

Results and discussion

The antimicrobial activity was performed against selected fungal and bacterial strains using tube dilution method. The antiproliferative potential was evaluated against human colorectal carcinoma (HCT116) and oestrogen- positive human breast carcinoma (MCF7) cancer cell lines using Sulforhodamine B assay and, results were compared to standard drugs, 5-fluorouracil and tamoxifen, respectively.

Conclusion

The performed antimicrobial activity indicated that compounds 3, 5, 6, 8 and 14 showed promising activity against selected microbial species. Antiproliferative screening found compound 14 to be the most potent compound against HCT116 (IC₅₀?=?71.8 µM), whereas Compound 6 was the most potent against MCF7 (IC₅₀?=?74.1 µM). Further, the molecular docking study has been carried to find out the interaction between active oxazole compounds with CDK8 (HCT116) and ER-α (MCF7) proteins indicated that compound 14 and 6 showed good dock score with better potency within the ATP binding pocket and may be used as a lead for rational drug designing of the anticancer molecule.

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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.     

Condensation of 5-hydroxy-2-methyl-4<Emphasis Type="Italic">H</Emphasis>-pyran-4-one with arylglyoxals. Synthesis and properties of 2-aryl-1-(3-hydroxy-6-methyl-4-oxo-4<Emphasis Type="Italic">H</Emphasis>-pyran-2-yl)ethane-1,2-diones

A convenient method was developed for the synthesis of previously unknown 1,2-diketones, based on the condensation of 5-hydroxy-2-methyl-4H-pyran-4-one with arylglyoxals. The study demonstrated the possibility of using these compounds to synthesize nitrogen-containing hetero cyclic systems bearing the 3-hydroxypyran-4-one moiety.     

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 of 4-hydroxy-5-methyl-2-[2-(4-oxo-4<Emphasis Type="Italic">H</Emphasis>-chromen-3-yl)ethenyl]-6<Emphasis Type="Italic">H</Emphasis>-1,3-oxazin-6-ones and their reaction with hydrazine

4-Hydroxy-6H-1,3-oxazin-6-ones containing a 3-vinylchromone fragment in the 2-position were synthesized. The direction of their reactions with hydrazine hydrate was found to depend on the solvent nature. The reaction in protic solvents (methanol, acetic acid) resulted in recyclization of both oxazine ring to 1,2,4-triazole and pyranone ring to pyrazole. Aprotic acetonitrile favored attack of hydrazine exclusively on the oxazine ring, while the 3-vinylchromone fragment remained intact.     

Synthesis and antimicrobial activity of novel substituted 4-[3-(1<Emphasis Type="Italic">H</Emphasis>-benzimidazol-2-yl)-4-hydroxybenzyl]-2-(1<Emphasis Type="Italic">H</Emphasis>-benzimidazol-2-yl)phenol derivatives

A series of novel substituted bis-benzimidazole derivatives were synthesized by reaction of 5,5′-methylenebis(2-hydroxybenzaldehyde) with various substituted o-phenylenediamines in glacial acetic acid. The structure of the newly synthesized compounds was elucidated by ¹H and ¹³C NMR, FT-IR, and MS spectra, and their antimicrobial activity against gram positive and gram negative bacteria and antifungal activity were evaluated. The thienyl-substituted derivative showed significant activity against Bacillus licheniformis. Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumonia (bacteria), and Fusarium solani (fungi). The activities of the fluoro-substituted substituted derivative against some bacterial strains and of the thienyl-substituted derivative against fungi were found to be similar to those of standard drugs.     

Alkylation of 2-(hydroxyimino)-5<Emphasis Type="Italic">H</Emphasis>-[1,3]thiazolo[3,2-<Emphasis Type="Italic">a</Emphasis>]-pyrimidin-3(2<Emphasis Type="Italic">H</Emphasis>)-ones

Alkylation products were obtained from ethyl 2-(hydroxyimino)-7-methyl-3-oxo-5-aryl-2,3- dihydro-5H-[1,3]thiazolo[3,2-a]pyrimidin-6-carboxylates at the treatment with alkyl halides, dimethyl sulfate, and diazomethane. Diazomethane alkylated the initial substrate at the oxygen atom of the carbonyl group of the thiazolidine fragment, the other reagents, at the oxygen atom of the hydroxyimino group.     

Three-component heterocyclization of 5-(arylmethylidene)pyrimidine-2,4,6(1<Emphasis Type="Italic">H</Emphasis>,3<Emphasis Type="Italic">H</Emphasis>,5<Emphasis Type="Italic">H</Emphasis>)-triones with aldehydes and amino acids

Previously unknown substituted 4-aryl-2,7,9-triazaspiro[4.5]decane-6,8,10-triones were synthesized in 50–70% yield by heating 5-(arylmethylidene)barbituric acids with N-methyl- or N-phenylglycine and para-formaldehyde or 4-methoxybenzaldehyde in boiling toluene for 14 h.     

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.     

Synthesis and structure of potassium 2-(pyridin-2-yl)-1<Emphasis Type="Italic">H</Emphasis>-benzo[<Emphasis Type="Italic">d</Emphasis>]imidazolate and preparation of related bis(diimine) ligands

A potassium derivative of 2-(pyridin-2-yl)-1H-benzo[d]imidazole (BenzimidK) is synthesized and structurally characterized (СIF file CCDC no. 1478559). The complex is used for the preparation of new bis(diimine) ligands containing different diimine fragments linked by the bridging (CH₂)₄ group.     

Tautomerism of azacycles: III. Molecular and crystal structures of 3<Emphasis Type="Italic">H</Emphasis>-and 2-phenyl-1<Emphasis Type="Italic">H</Emphasis>,4<Emphasis Type="Italic">H</Emphasis>-4,5-dihydro-1,2,4-triazole-5-thiones

Compounds capable of tautomerism: sulfanyl-1,2,4-triazole, its C-phenyl derivative, and the crystal hydrate of the latter, were studied by single crystal X-ray diffraction. In the crystals they exist in the form of 3-R-1(H),4(H)-4,5-dihydro-1,2,4-triazole-5-thione with a considerable contribution of the bipolar structure. Published data on the tautomerism of sulfanyl-1,2,4-triazoles and their N-substituted analogs and on the correlation between the spectral characteristics and structures of sulfanyl-1,2,4-triazoles capable of tautomerism are discussed.     

Synthesis of new 4-amino-5-(1,4-benzodioxan-2-yl)-4<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazole-3-thiol derivatives

Acylation and cyclization reactions of 4-amino-5-(1,4-benzodioxan-2-yl)-4H-1,2,4-triazole-3-thiol were studied. Acylation of the title compound with substituted benzoyl chlorides gave the corresponding amides, whereas its reactions with substituted benzoic acids in the presence of POCl3 were accompanied by cyclization with formation of triazolothiadiazoles containing a 1,4-benzodioxane substituent. 4-Amino-5-(1,4-benzodioxan-2-yl)-4H-1,2,4-triazole-3-thiol reacted with substituted benzaldehydes to afford the corresponding Schiff bases, and its alkylation with chloroacetic acid in ethanol in the presence of sodium acetate gave S-ethoxycarbonylmethyl derivative.     

Nitration of 1,3-dihydro-2<Emphasis Type="Italic">H</Emphasis>-imidazo[4,5-<Emphasis Type="Italic">b</Emphasis>]pyridin-2-one derivatives

Nitration of 1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one and its N-methyl derivatives at 0–5°C and 60°C gives 5-nitro-and 5,6-dinitro-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-ones, respectively. The latter can also be obtained by nitration of 5-mononitro derivatives under similar conditions. The nitration of 6-chloro-and 6-bromo-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-ones and their N-methyl-substituted analogs leads to the formation of the corresponding 6-chloro(bromo)-5-nitro compounds. The same products are formed in the nitration of 5,6-dichloro-and 5,6-dibromo-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-ones. In this case, the process involves replacement of the halogen atom in position 5 of the pyridine fragment by nitro group. The nitration of 6-bromo-5-methyl-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one is accompanied by oxidation of the 5-methyl group to carboxy.     

Synthesis of 7-(furan-2-yl)-7,8,10,10a-tetrahydro-6<Emphasis Type="Italic">H</Emphasis>-benzo[<Emphasis Type="Italic">c</Emphasis>]-chromen-6,9(6a<Emphasis Type="Italic">H</Emphasis>)-diones

Methods of synthesis were developed for 7-(furan-2-yl)-substituted 7,8,10,10a-tetrahydrobenzo[c] chromen-6,9-diones by regioselective [4+2]-cycloaddition of coumarin-3-carboxylic acids to 2-(3-trimethylsiloxybuta- 1,3-dien-1-yl)furans. The [4+2]-cycloaddition was efficiently catalyzed with L-proline.