Barium bismuth oxides with α-, γ-, and ɛ-Bi<Subscript>2</Subscript>O<Subscript>3</Subscript> structures

Three new barium bismuth oxides have been synthesized containing 2.15–2.72 mol % BaO with the integer composition BaBi₃₉O_59.5, BaBi₄₆O₇₀, and BaBi₄₀O₆₁ and a monoclinic, cubic, and triclinic structure, respectively. These double oxides are, likely, derivatives of α-, γ-, and ?-Bi₂O₃ phases. The effects of the crucible material and surrounding atmosphere on the course of the synthesis of these new barium bismuth oxides are elucidated.     

Chiral syntheses of 6′-β-fluoroaristeromycin, 6′-β-fluoro-5′-noraristeromycin and aristeromycin

Carbocyclic nucleosides substituted at the C-6′ position are receiving increasing attention. Chiral synthetic accessibility to the biologically promising 6′-β-fluoroaristeromycin is lacking. Its preparation and that of the 5′-nor analogue are described. Along the way, a new method to aristeromycin arose as an outgrowth of a requisite structure proof.     

Synthesis of a potential reactivator of acetylcholinesterase—1-(4-hydroxyiminomethylpyridinium)-3-(carbamoylpyridinium)propane dibromide

Two methods for the synthesis of a new unsymmetric bispyridinium oxime-1-(4-hydroxyiminomethylpyridinium)-3-(carbamoylpyridinium)propane dibromide are described. In vitro efficacy of this new oxime to reactivate sarin-inhibited acetylcholinesterase has been evaluated.     

2-(<Emphasis Type="Italic">N</Emphasis>-Alkylamino)-1-(trifluoroacetimidoyl)vinyl ketone derivatives as potential reagents in heterocyclic synthesis

A reaction of 3-acetyl-4-amino-5,5,5-trifluoropent-3-en-2-one diphenylboron chelate and ammonia or primary amines affords 4-amino- or 4-alkylamino-3-trifluoroacetimidoylpent-3-en-2-ones, new reagents which can be used for the synthesis of pyrimidines with trifluoromethyl group.     

An efficient route to 5-(hetero)aryl-2,4′- and 2,2′-bipyridines through readily available 3-pyridyl-1,2,4-triazines

A new route to substituted bipyridines based on a new method for the synthesis of substituted 3-pyridyl-1,2,4-triazines and their aza-Diels-Alder reactions is shown to be an efficient strategy for the preparation of structurally diverse bipyridine ligands.     

Synthesis and anticancer activity evaluation of (<Emphasis Type="Italic">E</Emphasis>)-3-{[5-(aryl)-1,3,4-oxadiazol-2-yl]methyl}-5-(3,4,5-trimethoxybenzylidene)thiazolidine-2,4-diones

A series of new substituted (E)-3-{[5-(aryl)-1,3,4-oxadiazol-2-yl]methyl}-5-(3,4,5-trimethoxy-benzylidene) thiazolidine-2,4-diones have been synthesized. The products have been characterized by their IR, ¹H NMR, ¹³C NMR, and mass spectral properties and evaluated for anticancer activity against four human cancer cell lines: A549, A375, MCF-7, and HT-29.     

Synthesis and Pharmacological Evaluation of Chlorinated <Emphasis Type="Italic">N</Emphasis>-Alkyl-3- and -5-(2-hydroxyphenyl)pyrazoles as <Emphasis Type="Italic">CB</Emphasis><Subscript>1</Subscript> Cannabinoid Ligands

Summary. The syntheses of several new 3- and 5-(4-chloro-2-hydroxyphenyl)-5- and -3-(2,4-dichlorophenyl)-1-alkylpyrazoles are reported. These syntheses started from simple chlorophenols, 2,4-dichlorobenzaldehyde or ethyl 2,4-dichlorobenzoate in order to prepare pyrazoles bearing three and four chloro substituents in certain positions. The affinity of these compounds towards the CB ₁ type cannabinoids receptors was then evaluated in human brain tissues (frontal cortex). The results showed that some of the compounds exhibit affinity towards this kind of receptors in the micromolar range.     

Synthesis of 2-[3-alkoxy-4-(hydroxy,alkoxy, acyloxy)phenyl]-5-methyl-1<Emphasis Type="Italic">H</Emphasis>-benzimidazoles

From substituted benzaldehydes of the vanillin series and 4-methyl-1,2-phenylene diaminein the presence of sodium hydrogen sulfite in DMF medium at 80°C new functionally substituted 2-[3-alkoxy-4-(hydroxy, alkoxy, acyloxy)phenyl]-5-methyl-1H-benzimidazoles were obtained in preparative yields.     

Selected β2-, β3- and β2,3-Amino Acid Heterocyclic Derivatives and Their Biological Perspective

Heterocyclic moieties, especially five and six-membered rings containing nitrogen, oxygen or sulfur atoms, are broadly distributed in nature. Among them, synthetic and natural alike are pharmacologically active compounds and have always been at the forefront of attention due to their pharmacological properties. Heterocycles can be divided into different groups based on the presence of characteristic structural motifs. The presence of β-amino acid and heterocyclic core in one compound is very interesting; additionally, it very often plays a vital role in their biological activity. Usually, such compounds are not considered to be chemicals containing a β-amino acid motif; however, considering them as this class of compounds may open new routes of their preparation and application as new drug precursors or even drugs. The possibility of their application as nonproteinogenic amino acid residues in peptide or peptide derivatives synthesis to prepare a new class of compounds is also promising. This review highlights the actual state of knowledge about β-amino acid moiety-containing heterocycles presenting antiviral, anti-inflammatory, antibacterial compounds, anaplastic lymphoma kinase (ALK) inhibitors, as well as agonist and antagonists of the receptors.     

Synthesis and antiviral properties of new derivatives of 2-(alkylsulfanyl)-6-[1-(2,6-difluorophenyl)cyclopropyl]-5-methylpyrimidin-4(3<Emphasis Type="Italic">H</Emphasis>)-one

Based on 2-(2,6-difluorophenyl)acetonitrile a synthesis was performed of new bioisosteric prochiral analogs of anti-HIV-1 active derivatives of 2-alkoxy-6-benzylpyrimidin-4(3Н)-one that we had previously obtained. The study using infected and nonifected strains of cells MT-4 made it possible to find in all prepared compounds a high anti-HIV activity whereas the cytotoxicity of the substances depended strongly on the structure of the alkylsulfanyl fragment of the molecule.     

4-(4-β-D-吡喃阿洛糖苷-苯基)-2-芳基-5-氰基-6-甲氧基吡啶的合成及镇静活性研究

以豆腐果苷为原料,与4-取代苯乙酮发生Schmidt-Claisen反应,得到一系列查儿酮结构的E-4-β-D-吡喃阿洛糖苷-苯乙烯基-4-取代苯乙酮衍生物3a-3h,其中3c、3e、3f为新化合物。 3a-3h在甲醇钠存在下,与1,3－丙二氰发生1,4-Michael加成,经关环、重排、氧化,得到4-(4-β-D-吡喃阿洛糖苷-苯基)-2-芳基-5-氰基-6-甲氧基吡啶系列豆腐果苷衍生物10a-10h,联氨催化还原10e而得到10i。共获得十二个未见文献报道的新化合物,其结构经1H NMR、IR和HRMS确证,并进行了药理活性筛选,结果表明,部分化合物具有比母体化合物更好的镇静催眠活性。同时,本文对Schmidt-Claisen反应存在的主要副反应进行了分析;对查儿酮与1,3－丙二氰在甲醇钠存在下反应生成吡啶衍生物反应机理进行了推导,提出了氧化脱氢形成吡啶的新机理。     

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.     

Synthesis,characterization, and antimicrobial activity of novel (<Emphasis Type="Italic">E</Emphasis>)-1-(aryl)-3-{3, 5-dimethoxy-4-[(1-(aryl)-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-4-yl)methoxy]phenyl}prop-2-en-1-ones

The new chalcone derivatives containing the 1,2,3-triazole ring system, namely, (E)-1-(aryl)-3-{3,5-dimethoxy-4-[(1-(aryl)-1H-1,2,3-triazol-4-yl)methoxy]phenyl}prop-2-en-1-ones, were synthesized in 65–88% yield by the “click chemistry” reactions of substituted acetophenones, 4-hydroxy-3,5-dimethoxy-benzaldehyde, and different substituted azides. The structure of the compounds was determined by the FT-IR, ¹H NMR, ¹³C NMR, and mass spectroscopic analyses. Compounds 6a–6l were screened for in vitro antimicrobial activity by the agar disc diffusion method.     

Synthesis of new derivatives of 5-alkyl-6-(2,6-dihalobenzyl)-2-(methylsulfanyl)pyrimidin-4(3<Emphasis Type="Italic">H</Emphasis>)-one and the features of their oxidation

The synthesis and features of the regioselective S-monomethylation of new 5-alkyl-6-(arylmethyl)-2-thioxo-2,3-dihydropyrimidin-4(1H)-ones were investigated, and also the character of the oxidative degradation of these compounds when treated with the system H₂O₂-AcOH.     

Synthesis of novel 2,2- and 1,1-linked dimeric ‘head-to-head’ N-alkoxybenzimidazoles

Synthesis of two new types of ‘head-to-head’ N,N-alkoxy bisbenzimidazoles is described. The proposed intermediate N-oxy benzimidazole from base-induced heterocyclization of N-alkylnitroanilines can be trapped with a biselectrophile (to give an N,N-linked dimer), or double heterocyclization of dimeric nitroanilines can be intercepted by electrophile trapping of both N-oxybenzimidazole termini to give C2,C2-linked dimers. These represent two regioisomeric motifs constituting new classes of benzimidazole dimers.     

Synthesis and properties of substituted [3-(2-hydroxyphenyl)-1<Emphasis Type="Italic">H</Emphasis>-1,2,4-triazol-1-yl]acetonitriles

Alkylation of 3-substituted 5-(2-hydroxyphenyl)-1H-1,2,4-triazoles with chloroacetonitrile gave hitherto unknown N-cyanomethyl derivatives whose structure was determined by X-ray analysis and ¹H and ¹³C NMR spectroscopy. Condensation of substituted [3-(2-hydroxyphenyl)-1H-1,2,4-triazol-1-yl]acetonitriles at the activated methylene group with acetone led to the formation of new 3-methyl-2-triazolylbut-2-enenitrile derivatives.     

Formation of cage phosphonate via hydrolysis of 2-(5-methyl-2-phenyl-2<Emphasis Type="Italic">H</Emphasis>-1,2,3-diazaphosphol-4-yl)-1,5-dioxo-4-trifluoromethyl-4-ethoxycarbonylbenzo[<Emphasis Type="Italic">f</Emphasis>]-1,3,2-dioxaphosphepine

A new approach to obtaining of caged bicyclic phosphonate, 4-hydroxy-3-trifluoromethyl-3-ethoxycarbonyl-8-(1-phenylhydrazonoethyl)-5,6-benzo-2,7,1-dioxaphosphabicyclo[3.2.1^1.5]octane, based on hydrolysis of 2,5-dioxobenzo[f]1,3,2-dioxaphosphepine derivative bearing 5-methyl-2-phenyl-2H-1,2,3-diazaphosphol-4-yl substituent at the phosphorus was developed. The hydrolysis process includes elimination of P(II) atom and intramolecular cyclization involving endocyclic carbonyl group of the phosphepine. Structure of the caged phosphonate was established by NMR and XRD methods.     

Facile synthesis of 2-(substituted amino)-4<Emphasis Type="Italic">H</Emphasis>-thieno[3,2-<Emphasis Type="Italic">e</Emphasis>]-1,3-thiazin-4-ones

Interaction between 2,5-dichlorothiophene-3-carbonyl isothiocyanate, accessible via 2,5-dichlorothiophene-3-carbonyl chloride, and model heterocyclic amines produced the respective 2,5-dichloro-N-(substituted aminocarbonothioyl)thiophene-3-carboxamides. Upon heating, the deprotonated form of the latter underwent intramolecular cyclization to deliver the corresponding 2-(substituted amino)-4H-thieno[3,2-e]-1,3-thiazin-4-ones. The structures of these new bicyclic derivatives and their acyclic precursors are based on microanalytical and spectral (IR, MS, and NMR) data. Correspondence: Rajab Abu-El-Halawa, Chemistry Department, Faculty of Science, Al al-Bayt University, Mafraq, Jordan.     

4′-(2-(2-Ethoxyethoxy)ethoxy)biphenyl-4-carboxylic acid—a polar smectogen for amphipathic liquid crystals

We describe a new calamitic smectogen and some of its esters with a three-block molecular architecture (polar oxyethylene chain, rigid biphenyl and non-polar aliphatic chain) which were characterised by a combination of optical, thermical, X-ray and computational techniques. The title compound is a valuable smectogenic building block for amphipathic functional organic materials.     

(R)-6,6′-Bis(trifluoromethanesulfonyl)-2,2′-dihydroxy-1,1′-binaphthyl: a new ligand for asymmetric synthesis

The new (R)-6,6′-bis(trifluoromethanesulfonyl)-2,2′-dihydroxy-1,1′-binaphthyl (1) has been synthesized and proved to generate highly active zirconium-based catalysts for asymmetric Mannich-type reactions.