Synthesis and mesomorphic properties of the homologous series of 4′-bromophenyl 4′'-[(4-n-alkoxy-2,3,5,6 tetrafluorophenyl)ethynyl]benzoates

Abstract

A homologous series of 4′-bromophenyl 4′'-[(4-n-alkoxy-2,3,5,6-tetrafluoro-phenyl)ethynyl]benzoates has been synthesized. The transition temperatures were studied by polarizing optical microscopy. The compounds exhibit nematic and smectic A phases.     

Preparation and properties of copper tetra-4-[(4′-carboxy)phenylamino]phthalocyanine

Interaction of 4-nitrophthalonitrile with 4-aminobenzoic acid in dimethylsulfoxide in the presence of potassium carbonate has led to 4-[(4′-carboxy)phenylamino]phthalonitrile. From the latter, copper tetra-4-[(4′-carboxy)phenylamino]phthalocyanine has been prepared via the template synthesis. The spectral properties of the product have been studied. It has been demonstrated that in aqueous alkaline solutions the complex associates, whereas in dimethylformamide it predominantly exists in the monomeric form.     

Synthesis and mesomorphic properties of n-butyl-4- [4-((4-n-alkoxyl-tetrafluorophenyl)ethynyl)benzyloxy]benzoates

A homologous series of n-butyl-4-[4-((4-n-alkoxyl-tetrafluorophenyl)ethynyl)benzyloxy]benzoates have been synthesized.Their phase transition temperatures have also measured by polarizing textural observation and confirmed by DSC.     

Preparation and properties of poly-[4-4′-(p-biphenylene)amide]

Poly-[4-4′-(p-biphenylene)amide] was prepared by polycondensation of 4-amino-4′-carboxyl-biphenyl at 260–270°C in a nitrogen atmosphere. The thermal behaviour of the polyamide and the weight loss of the monomer, during the reaction of polycondensation, were investigated by Differential Thermal Analysis (DTA) and by Thermalgravimetric Analysis (TGA). Infrared spectrum and intrinsic viscosity of the polyamide were also studied.     

Diastereoselective and enantioselective synthesis of 4′-aza analogues of 2′,3′-dideoxynucleosides

A diastereo- and enantioselective synthesis of 4′-aza analogues of 2′,3′-dideoxynucleosides has been designed by the strategy of the 1,3-dipolar cycloaddition reaction of a Vasella-type nitrone. The reaction leads to (1′R)- and (1′S)-4′-aza analogues of 2′,3′-dideoxythimidine and fluorouridine, in enantiomerically pure forms.     

Synthesis and mesomorphic properties of fluorinated phenyl 4‐[(4‐n‐alkoxy‐2,3‐difluorophenyl)ethynyl]benzoates

Three series of fluorinated phenyl 4‐[(4‐n‐alkoxy‐2,3‐difluorophenyl)ethynyl]benzoate liquid crystals have been synthesized. Their phase transition temperatures were measured by texture observation in a polarizing microscope and confirmed by DSC. Their mesomorphic properties and fluoro‐substituent effects were studied in detail.     

The synthesis of azole derivatives from 3-[(4-methylphenyl)amino]propanehydrazide and its N′-phenylcarbamoyl derivatives, and their antibacterial activity

Abstract  

5-[2-[(4-Methylphenyl)amino]ethyl]-1,3,4-oxadiazol-2(3H)-thione, 5-[2-[(4-methylphenyl)amino]ethyl]-1,3,4-oxadiazol-2(3H)-one, N-(2,5-dimethyl-1H-pyrrol-1-yl)-3-[(4-methylphenyl)amino]propanamide, and a series of N-[(phenylcarbamoyl)amino]-3-[(4-methylphenyl)amino]propanamides and 3-[(4-methylphenyl)(phenylcarbamoyl)amino]-N-[(phenylcarbamoyl)amino]propanamides, and their thio analogues were synthesized from 3-[(4-methylphenyl)amino]propanehydrazide. 1,3,4-Oxadiazole-2(3H)-thione was converted to 4-amino-2,4-dihydro-5-[2-[(4-methylphenyl)amino]ethyl]-3H-1,2,4-triazole-3-thione, whereas cyclization of N′-phenylcarbamoyl derivatives provided thiazole, oxadiazoles, and thiadiazole, as well as triazole derivatives. Two of the synthesized compounds exhibited good antibacterial activity against Rhizobium radiobacter.     

A new method of the synthesis of bis-μ-[(methylenedicyclopentanone-2,2′-dioximato)-triphenylantimony]

Bis-μ-[(methylenedicyclopentanone-2,2′-dioximato)triphenylantimony] is prepared by the reaction of triphenylantimony with methylenedicylopentanone-2,2′-dioxime in the presence of hydrogen peroxide. According to the data of X-ray structural analysis, this compound has centrosymmetric structure with two Ph₃Sb fragments connected with each other via dioxime bridges. The antimony atoms have screwed trigonalbipyramidal coordination, the Sb-C bond lengths vary in the range of 2.097(6)–2.122(4) Å, the Sb-O distances equal to 2.073(3) and 2.064(3) Å. There are short Sb—N intramolecular contacts in the molecule [2.876(4), 2.905(4) Å].     

N-Alkyl-N′-[(alkyl/aryl)(alkoxy/aroxy)phosphoryl]ureas: synthesis and extraction properties toward f-elements

A reaction of chlorophosphonates R¹R²P(O)Cl with NaOCN and subsequent treatment with octylamine lead to phosphorylureas R¹R²P(O)NHC(O)NHC₈H₁₇-n (R¹ = EtO, PhO; R² = Me, Ph). Their extraction capability toward U^VI and a number of tervalent lanthanides (La^III, Nd^III, Ho^III, Yb^III) was studied. Efficiency and selectivity of these ligands in the extraction of f-elements from nitric acid solutions to chloroform were compared with extraction properties of a model phosphine oxide-type phosphorylurea MePhP(O)NHC(O)NHC₈H₁₇-n and carbamoylphosphine oxide Ph₂P(O)CH₂C(O)NBu₂.     

X-ray investigation of the nematic and reentrant nematic phases of N-[(4-n-octyloxybenzoyloxy)-salicilidene]-4′-cyanoaniline

We have performed an X-ray scattering study of the nematic-smectic A and reentrant nematic-smectic A phase transitions in N-[(4-n-octyloxybenzoyloxy)-salicilidene]-4′-cyanoaniline (OOBOSCA). A diffractometer with a linear position sensitive detector was used. The results show that the smectic phase in OOBOSCA is of the A_d type with an interlayer spacing incommensurate with the molecular length L; d ∽ 1·2L. In the reentrant nematic phase two types of fluctuation modes were found. One of them corresponds to the monolayer wavevector q ₁ ∽ 2π/L, and the other is due to the partial bilayer fluctuations with the wavevector q ₂ ∽ 0·8q ₁. The temperature dependences of the interlayer spacing, X-ray scattering intensity and longitudinal correlation length for both types of layering in the reentrant nematic phase are presented. The change of the fluctuation regime from S_Ad, to S_Cd type with decreasing temperature in the reentrant nematic phase of OOBOSCA was found. The results are discussed on the basis of models with competing order parameters. The influence of alkyl chain flexibility on the stability of a partial bilayer smectic phase is also considered.     

Synthesis and structure of bis-μ-[(methylenedicyclopentanone-2,2′-dioximato)triphenylantimony]

The reaction of pentaphenylantimony with methylenedicyclopentanone-2,2 dioxime affords bis--[(methylenedicyclopentanone-2,2-dioximato)triphenylntimony] having, according to the X-ray diffraction data, a centrosymmetric structure with two Ph₃Sb moieties linked by dioxime bridges. The antimony atom has a distorted trigonal bipyramidal coordination. The Sb-C bond lengths vary in an interval of 2.111(1)–2.137(3) , and the Sb-O distances are equal to 2.064(1) and 2.0663(9) . The molecule contains short intramolecular contacts SbN of 2.876(1) and 2.910(1) .Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 172–176.Original Russian Text Copyright © 2005 by Sharutin, Molokova, Sharutina, Alyabeva, Kukharev, Akimova, Pushilin.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

The total synthesis and biological evaluation of nafuredin-γ and its analogues

Nafuredin (1) is converted to nafuredin-γ (2) under mild basic conditions and both compounds exhibit the same inhibitory activity and selectivity against NADH-fumarate reductase (complex I). The total synthesis of 2 was achieved by a convergent approach using Stille coupling. The structural elements required for inhibitory activity against NADH-fumarate reductase (complex I) were then investigated by evaluation of nafuredin-γ (2) and its structural analogues.     

Structural characterization,thermal investigation,and liquid crystalline behavior of 4-[(4-chlorobenzyl)oxy]-3,4′-dichloroazobenzene

Using the Williamson method, a new dye 4-[(4-chlorobenzyl)oxy]-3,4′-dichloroazobenzene (CODA) with liquid crystalline properties was synthesized. The structure and the thermal behavior of CODA were investigated by means of nuclear magnetic resonance, X-ray diffraction, differential scanning calorimetry, and light polarized optical microscopy techniques. The thermophysical processes were monitored by heating–cooling cycles, but the formation of liquid crystal phases were exhibited only for small values of the cooling rates. For the first heating–cooling cycle, the melting and the solidification processes, thus the characteristic temperatures, are shifted to higher values when compared to the following cycles.     

The application of copolymer-coated graphene oxide-Fe3O4 in the highly efficient synthesis of 2′-aminospiro[indeno[1,2-b]quinoxaline-11,4′-[4'H] pyran]-3′-carbonitrile and 2′-aminospiro[indeno-2,4′-[4'H]pyran]-3′-carbonitrile

A magnetic nanocomposite based on graphene oxide was prepared. Fe₃O₄ nanoparticles were loaded on graphene oxide sheets and GO-Fe₃O₄ was covered by aniline-pyrrole copolymer to afford poly(Py-co-Ani)@GO-Fe₃O₄. This nanocomposite was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, vibrating sample magnetometry, X-ray diffraction, thermogravimetric analysis, and X-ray photoelectron spectroscopy techniques, and its catalytic activity was evaluated in the multicomponent synthesis of 2′-aminospiro[indeno[1,2-b]quinoxaline-11,4′-[4'H]pyran]-3′-carbonitrile and 2′-aminospiro[indeno-2,4′-[4'H]pyran]-3′-carbonitrile derivatives. This magnetically separable catalyst is heterogeneous noncorrosive, highly efficient, and reusable.     

Improved synthesis of C4α- and C4β-methyl analogues of 2-aminobicyclo[3.1.0]hexane-2,6-dicarboxylate

An efficient and divergent synthesis of C4α- and C4β-methyl-substituted analogues of 2-aminobicyclo[3.1.0]hexane 2,6-dicarboxylate, which are important tools in the study of metabotropic glutamate receptor function, has been achieved. By taking advantage of an unanticipated facial selectivity of the bicyclo[3.1.0]hexane ring system, either the C4α- or C4β-methyl substituent was introduced in a highly stereoselective and high-yielding manner.     

The synthesis, deprotection and properties of poly(γ-benzyl-l-glutamate)

Diethylamine, di-n-hexylamine, dicyclohexylamine and triethylamine have been used as initiators for the ring-opening polymerization of γ-benzyl-l-glutamate N-carboxyanhydride (BLG NCA) to synthesize poly(γ-benzyl-l-glutamate) (PBLG). The relationship between the molecular weight of PBLG and the molar ratio of monomer and initiator was studied. With dicyclohexylamine as initiator, the influence of monomer concentration, and reaction temperature and time on the polymerization of BLG NCA was examined. Three reagents were used for the deprotection of benzyl groups in PBLG, including hydrobromic acid/acetic acid (33 wt.%), NaOH aqueous solution and trimethylsilyl iodide (TMSI). Through examining the molecular weight of PLGA obtained using different deprotection methods, it was revealed that TMSI could minimize chain cleavage in the process of deprotection and retain the degree of polymerization. The biocompatibilities of PBLG obtained using different initiators were evaluated by a live/dead assay against L929 fibroblast cells. The in vitro cytotoxicities of PLGA obtained using different deprotecting agents were evaluated by a methyl thiazolyl tetrazolium assay. The results revealed that both PBLG and PLGA exhibited good biocompatibilities.