Liquid crystalline behaviour of mixtures of structurally dissimilar mesogens in binary systems

We have studied four binary systems comprising four ester components, viz. 4-nitrophenyl-4′-n-alkoxybenzoates (wheren-alkoxy isn-butoxy, C₄,n-hexyloxy, C₆,n-octyloxy, C₈ andn-decyloxy, C₁₀) and one azo component, 4-n-decyloxy phenylazo-4′-isoamyloxy benzene. A variety of mesomorphic properties are observed in these mixtures. The properties of these systems are discussed on the basis of phase diagrams.     

Preparation and characterization of side-chain liquid crystalline polymers containing chenodeoxycholic acid residue

A series of new side-chain liquid crystalline polymers containing chenodiol residue derived from 24-[4′-hydroxybiphenyl-4-yl-4-(allyloxy)benzoyloxy]-3α,7α-di{n-[4′-(4-ethoxybenzoyloxy)biphenyl-4-yloxy]-n-oxoalkanoyloxy}-5β-cholane was designed and prepared. The chemical structures of the monomer and polymer were confirmed by Fourier transform infrared and ¹H NMR spectra. The mesomorphic properties of monomer and polymer were investigated by differential scanning calorimetry, thermogravimetric analysis, polarizing optical microscopy, and X-ray diffraction. The side-chain liquid crystalline polymers revealed wide mesophase temperature range and high thermal stability, and they showed nematic liquid crystalline phase. The influence of flexible space group length on thermal properties and specific rotation was examined.     

Hypercoordinated gold(I) compounds

A hypercoordinated 2,2′-diaurated 4-tert-butylbiphenyl derivative, which contains an intramolecular Au...Au secondary bond, was first synthesized by the reaction of 2,2′-dilithio-4-tert-butylbiphenyl with ClAuPPh₃. The structure of the complex was established by X-ray structural analysis,¹H and³¹P NMR spectroscopy, and fast-atom bombardment mass spectrometry. For Part 3, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2244–2247, December, 1997.     

New glycosidic and other constituents from hulls of <Emphasis Type="Italic">Oryza sativa</Emphasis>

Three new compounds, 4-hydroxymethylene-7-(9,9,13-trimethylcyclohexyl)-heptanyl-3′,7′,7′-trimethylcyclohexa-2′,4′-dien-1′-oate (1), 1-(n-hexadec-7-enoxy)-6-(n-octadecanoxy)-β-D-glucopyranoside (2), and (Z)-12-hydroxy-9-octadecenoic acid-12-β-D-glucopyranoside (3), along with the known compound hexacosanoic acid (4), were isolated and identified from the rice hulls of Oryza sativa. Their structures were elucidated by 1D and 2D NMR spectroscopic techniques (¹H-¹H COSY, ¹H-¹³C HETCOR, DEPT) aided by EIMS, FABMS, HRFABMS, and IR spectra. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 344–347, July–August, 2007.     

Asymmetric syntheses with BINOL-based imidoyl azide

Thermal decomposition of 2,4,6-trimethylphenyl and (+)-2′-methoxy-1,1′-binaphthalen-2-yl (4-methylphenylsulfonyl)azidimidocarbonates in the presence of norbornene, methyl acrylate, and camphene was studied. (+)-2′-Methoxy-1,1′-binaphthalen-2-yl (4-methylphenylsulfonyl)azidimidocarbonate reacted with norbornene to give (+)-exo-2′-methoxy-1,1′-binaphthalen-2-yl N-(4-methylphenylsulfonyl)-3-azatricyclo-[3.2.1.0^2,4]octane-3-carboximidoate, while in the reaction with methyl acrylate a mixture of stereoisomeric methyl 1-[(2′-methoxy-1,1′-binaphthalen-2-yloxy)(4-methylphenylsulfonylimino)methyl]aziridine-2-carboxylates was obtained. The reaction of 2,4,6-trimethylphenyl (4-methylphenylsulfonyl)azidimidocarbonate with (−)-camphene involved insertion of intermediate nitrene into the exocyclic double bond with formation of 2,4,6-trimethylphenyl N-(3,3-dimethylbicyclo[2.2.1]heptan-2-ylidenemethyl)-N′-(4-methylphenylsulfonyl)-imidocarbamate as a 3: 1 mixture of E,E and E,Z diastereoisomers in good yield. Published in Russian in Zhurnal Organicheskoi Khimii, 2008, Vol. 44, No. 10, pp. 1495–1500. The text was submitted by the authors in English.     

1H and13C NMR study of tin-containing sulfoxide, sulfimide, and sulfoximide

Sulfoxide RS(O)R′ (1), sulfimide RS(=NSO₂Ar)R′ (2), and sulfoximide RS(O)(=NSO₂Ar)R′ (3) (R=Me₃Sn(CH₂)₃, R′=n-C₅H₁₁, Ar=4-C₆H₄Cl) were investigated by¹H and¹³C NMR spectroscopy. Unlike 3, compounds 1 and 2 have a cyclic structure due to the intramolecular donor-acceptor S→Sn interaction. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1966–1969, November, 1997.     

Preparation of a zwitterionic trichloroplatinum(II) complex with an alkylbipyridinum ligand and its reaction in dmso-<Emphasis Type="BoldItalic">d</Emphasis><Subscript>6</Subscript> solution

A zwitterionic trichloroplatinum(II) complex PtCl₃(4,4′-bpy-N-ⁿBu) (1) was prepared by an aqueous reaction of [4,4′-bpy-N-ⁿBu]Cl with K₂PtCl₄, and was characterized by ¹H-n.m.r. and IR spectroscopy as well as elemental analysis. Dissolving (1) into dmso-d ₆ at 25 °C yields a mixture of the complexes, cis-PtCl₂(4,4′-bpy-N-ⁿBu)(dmso-d ₆) (2-cis), trans-PtCl₂(4,4′-bpy-N-ⁿBu)(dmso-d ₆) (2-trans), [4,4′-bpy-N-ⁿBu]Cl and PtCl₂(dmso-d ₆)₂. Ratio of the products in the dmso-d ₆ solution changed depending on the temperature and the total concentration of the complexes. These compounds are in equilibrium via isomerization reaction between (2-cis) and (2-trans) and via displacement reaction of the alkylbipyridinium ligand of (2-cis) and (2-trans) with dmso-d ₆ to form [4,4′-bpy-N-ⁿBu]Cl and PtCl₂(dmso-d ₆)₂.     

A new method for analysis of disulfide-containing proteins by matrix-assisted laser desorption ionization (MALDI) mass spectrometry

A simple and high-throughput method for the identification of disulfide-containing peptides utilizing peptide-matrix adducts is described. Some commonly used matrices in MALDI mass spectrometry were found to specifically react with sulfhydryl groups within peptide, thus allowing the observation of the peptide-matrix adduct ion [M+n+n′ matrix+H]⁺ or [M+n+n′ matrix+Na]⁺ (n = the number of cysteine residues, n′=1, 2,…, n) in MALDI mass spectra after chemical reduction of disulfide-linked peptides. Among several matrices tested, α-cyano-4-hydroxycinnamic acid (CHCA, molecular mass 189 Da) and α-cyano-3-hydroxycinnamic acid (3-HCCA) were found to be more effective for MALDI analysis of disulfide-containing peptides/proteins. Two reduced cysteines involved in a disulfide bridge resulted in a mass shift of 189 Da per cysteine, so the number of disulfide bonds could then be determined, while for the other matrices (sinapinic acid, ferulic acid, and caffeic acid), a similar addition reaction could not occur unless the reaction was carried out under alkaline conditions. The underlying mechanism of the reaction of the matrix addition at sulfhydryl groups is proposed, and several factors that might affect the formation of the peptide-matrix adducts were investigated. In general, this method is fast, effective, and robust to identify disulfide bonds in proteins/peptides.     

Isoflavone glycosides from the bark of Amorpha fruticosa

Four known isoflavone glucosides have been isolated from the bark of Amorpha fruticosa, which is a traditional remedy plant, for the first time. They were elucidated as 3′-hydroxy-4′-methoxyisoflavone-7-O-β-D-glucopyranoside (1), 4′,6-dimethoxyisoflavone-7-O-β-D-glucopyranoside (2), 4′-methoxyisoflavone-7-O-β-D-glucopyranoside (3), and 3′,5-dihydroxy-4′-methoxyisoflavone-7-O-β-D-glucopyranoside (4), based on the UV, FT-IR, EIMS, FABMS, HREIMS, and NMR (¹H and ¹³C, DEPT, COSY, NOESY, HMQC, and HMBC) data. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 336–338, July–August, 2006.     

Synthesis and photochromic properties of a new biindenylidenedione compound bearing hydroxylphenyl groups in crystal state

A new biindenylidenedione compound, named [trans-anti-3,3′-Di-p-hydroxyl phenyl-3,3′-dihydroxy-[2,2′-bi-1H-indene]-1,1′-dione] (2) was synthesized and characterized by means of ¹H-NMR, IR, MS and X-ray crystallographic diffraction techniques. The photochromic behavior was investigated by means of UV–Vis spectroscopy, and the results showed that the inclusion complex of 2 with guest solvent N,N-dimethylformamide (DMF) did not exhibit photochromism in crystal state. The structure–property relation was discussed briefly in context to the intermolecular interactions and the solvent-dependent effect on photochromism.     

Analysis of silica hydride and surface hydrosilation reactions by solid-state NMR in the preparation of<Emphasis Type="Italic"> p</Emphasis>-chlorobenzamide bonded silica phase

²⁹Si and ¹³C CP-MAS NMR spectroscopy was used to follow the conversion of native silica to a p-chlorobenzamide bonded silica material. The benzamide bonded phase was prepared via a hydrosilation reaction of a hydride silica intermediate with p-chloro-N-allylbenzamide. Solid-state NMR was used to show the disappearance of reactive surface hydride species (M_H) and to identify newly formed bonded chemical species on the silica surface. DRIFT spectroscopy, elemental analysis, and specific surface-area determinations (BET) of the prepared phases are also reported.     

Diels-alder reaction with cyclic sulfones. 9.* Synthesis of 10-oxo-1h-tetrahydrofluo-reno[2,1-b]thiophene dioxides*2

The treatment of 5-aryl-4′,6′-dioxo-2,3,3a,4,5,6-hexahydrospiro-[benzothiophene-4,5′-1,3-dioxane] 1,1-dioxides with boron trifluoride etherate in dichloroethane leads to the formation of products of intramolecular acylation, namely, the corresponding 10-oxo-1H-5,5a,10a,10b-tetrahydrofluoreno-[2,1-b]thiophene dioxides. In all cases, 5-aryl-4-carboxyhexahydrobenzo[b]thiophene 1,1-dioxides were also isolated. The product ratio depends on the structure of the aromatic substituent at C(5) of the spiro- adducts. The structure of 4-carboxy-5-(2-methoxyphenyl)-7-methyl -2,3,3a,4,5,6-hexahydro-benzo[b]thiophene 1,1-dioxide was confirmed by X-ray diffraction structural analysis. ^*For Communication 9 see [1]. ^*2Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1503–1512, October, 2008.     

Triterpene glycosides ofHedera canariensis III. Determination of the structures of glycosides L-F1, L-F2, and L-I2 from the leaves of Algerian ivy

The leaves of Algerian ivyHedera canariensis Willd. (Araliaceae) have yielded two new triterpene glycosides — caulophyllogenin 3-O-α-L-rhamnopyranosyl-(1→2)-O-α-L-arabinopyranoside (L-F₂) and its 28-O-α-L-rhamnopyranosyl-(1→4)-O-β-D-gentiobiosyl ester (L-I₂) - and also the previously known hederagenin 3-O-α-L-rhamnopyranosyl-(1→2)-O-β-D-glucopyranoside (L-F₁). The structures of the glycosides were established on the basis of chemical transformations and¹H and¹³C NMR spectroscopy. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 777–781, November–December, 1998.     

A novel chromone-substituted trimeric dihydroflavonol from <Emphasis Type="Italic">Anogeissus pendula</Emphasis>

A new chromone-substituted dihydrotriflavonol, (2S,3S)[6-{(3S) 3″,5″-dihydroxy-6″-methoxydihydrochromone}5,3′,4′,5′-tetrahydroxy-7-methoxy-3-O-8-dihydroflavone]₂ 3-O-8[6-{(3S) 3″,5″-dihydroxy-6″methoxydihydrochromone}3,5,3′,4′,5′-pentahydroxy-7-methoxydihydroflavonol] was isolated from the leaves of Anogeissus pendula. The structure was determined by UV, ¹H NMR, ¹³C NMR, HMBC, and CD data.     

Alkylation of salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides with alkyl halides and dimethyl sulfate

Salts ofN-(β-hydroxyalkyl)-N′-hydroxydiazeneN-oxides, RCH(OH)CH₂N(O)=NO⁻ M⁺ (R=Me, Prⁱ, or Bu^t; and M=Li, Na, K, Ag, NH₄, or Me₄N), were prepared. Their alkylation with alkyl halides R′X (X=Cl, Br, or I) and dimethyl sulfate was studied. Generally, alkylation afforded mixtures ofN-(β-hydroxyalkyl)-N′-alkoxydiazeneN-oxides RCH(OH)CH₂N(O)=NOR′ andO-alkyl-N-(β-hydroxyalkyl)-N-nitrosohydroxylamines RCH(OH)CH₂N(NO)OR′. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1996–2001, October, 1998.     

Voltammetry of electroactive liquid redox systems: anion insertion and chemical reactions in microdroplets of para-tetrakis(6-methoxyhexyl) phenylenediamine, para- and meta-tetrahexylphenylenediamine

The effect of the structure of the organic precursor molecule on the electroinsertion of anions and on the formation of materials in the ionic liquid state is compared for three compounds, para-N, N, N′, N′-tetrahexylphenylenediamine (p-THPD), meta-N, N, N′, N′-tetrahexylphenylene diamine (m-THPD), and para-N, N, N′, N′-tetrakis(6-methoxyhexyl)phenylenediamine (p-TMHPD), by characterising their condensed phase voltammetric properties in aqueous media. The electrochemically driven anion insertion in p-THPD and p-TMHPD in the presence of ClO₄ ⁻, F⁻, Cl⁻, Br⁻, I⁻, and SO₄ ²⁻ is shown to be extremely sensitive to structure. The introduction of the methoxy end groups in p-TMHPD causes (1) a considerable shift to more negative electroinsertion potentials, (2) a less stable response which upon continuous cycling decreases, and (3) considerably lower anion selectivity. For the insertion of sulfate, only p-TMHPD yields an electrochemical response which is shown to be consistent with insertion of the dianion SO₄ ²⁻. The electrochemical oxidation of a deposit of m-THPD is accompanied by anion insertion and a chemical reaction step in an EC-type electrochemical process. The product of the chemical step is electrochemically active and results in a new reversible electroinsertion process. Starting materials and products of the microdroplet reactions are characterised by Maldi-TOF mass spectrometry and a reaction mechanism based on condensed phase polymerisation is proposed. Received: 15 November 1999 / Accepted: 2 December 1999     

3,6-Di-tert-butyl-o-benzosemiquinone complexes of copper(1) with bidentate bis(diphenylphosphine) ligands. Synthesis, structures, and properties

New mononuclear 3,6-di-tert-butyl-o-benzosemiquinone complexes of copper(1) with bis(diphenylphosphine) ligands were synthesized: (DBSQ)Cu(dppe) (1) (DBSQ=3,6-di-tert-butyl-o-benzosemiquinone and dppe=1,2-bis(diphenylphosphino)ethane), (DBSQ)Cu(dppp) (2) (dppp=1,3-bis(diphenylphosphino)propane), (DBSQ)Cu(dppn) (3) (dppn=2,2′-bis(diphenylphosphino)-1,1′-binaphthyl), and (DBSQ)Cu(dppfc) (4) (dppfc=1,1′-bis(diphenylphosphino)ferrocene). The compositions and structures of complexes1–4 were characterized by elemental analysis and electronic absorption, IR, and ESR spectroscopy. The molecular structures of complexes3 and4 were established by X-ray diffraction analysis. The reactions of elimination and replacement of neutral ligands in the coordination sphere of the complexes were studied by ESR spectroscopy. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2333–2340, November, 1998.     

Alkaloids ofArundo donas VII. A spectroscopic and X-ray structural investigation of arundinine—A new dimeric alkaloid from the epigeal part ofArundo donax

FromArundo donax L. we have isolated the new dimeric alkaloid arundinine, with the composition C₂₃H₂₈N₄O, the structure of which has been established on the basis of its physicochemical characteristics and¹H and¹³C NMR spectroscopy, including 1D and 2D experiments in both homo- and heteronuclear regimes. The proposed structure—3a-(3′-dimethylaminoethylindol-5′-yloxy)-1-methylpyrrolidino[1a,3a-b]indoline — has been confirmed by x-ray structural analysis (XSA). Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (371) 120 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 790–795, November–December, 1998.     

Synthesis of 5-bromo-4-dibromoamino-3-phenylisothiazole and its light-induced conversion into 3,7-diphenylbisisothiazolo[4,5-b:4′,5′-e]pyrazine

When irradiated with UV light, 5-bromo-4-dibromoamino-3-phenylisothiazole is converted into 3,7-diphenylbisisothiazolo[4,5-b:4′,5′-e]pyrazine andN,N′-bis(5-bromo-3-phenylisothiazol-4-yl)diazene. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 957–959, May, 2000.     

Synthesis and structural aspects of urea/dialkylamine inclusion compounds

The synthesis and structural aspects of urea host-guest inclusion compounds containing linear secondary alkylamines (dibutyl-,dipentyl-, dihexyl-, dioctyl-) at 25°C are reported. Elemental analysis,¹³C CP-MAS NMR and¹H-NMR Spectroscopy, and Powder X-ray Diffraction Analysis confirm the inclusion process. The basic host structure of the products is similar to that of urea-hydrocarbon systems.¹³C MAS-NMR experiments show chemical shift differences for the confined guest molecule with respect to the liquid phase. Stoichiometry and |c _g| values for the inclusion compounds with dipentyl-and dihexylamine suggest a commensurate structure.