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1.
N. Narendra 《Tetrahedron letters》2010,51(47):6169-6173
A simple protocol for the synthesis of a new class of trithiocarbonate-linked peptidomimetics and neoglycosylated amino acids is described. N-Protected amino alkyl thiols were treated with CS2 in the presence of triethylamine (TEA) to generate trithiocarbonate salt, which upon reaction with appropriate halides afforded dipeptidomimetics in good yields. Further, the procedure was also extended for the synthesis of N,N′-orthogonally protected trithiocarbonate-linked dipeptidomimetics. 相似文献
2.
Preparation and characterization of microemulsions consisting of a plant-derived alkyl polyglycoside (APG) surfactant and the essential oil of Melaleuca alternifolia (tea tree) was studied. This nonionic APG surfactant used was Triton CG-110 with a CMC at 1748 ppm at 25 °C. Tea tree oil (TTO) was extracted from tea tree leaves by Triton CG-110-assisted hydrodistillation method. The preparation of the microemulsion was aided by the construction of pseudo-ternary phase diagrams, which were investigated at the different weight ratios of surfactant mixtures (Smix = Triton CG-110/PPG) as 0.6:1, 1.8:1, 1:0 with hydrodistilled and commercial TTO by water titration method at room temperature. Particularly, structure of microemulsion was identified by electrical conductivity and viscosity. Moreover, shelf stability of some microemulsion made of 1% TTO with various concentration of Triton CG-110/PPG (1.8:1 w/w) were monitored for over a two-month period with dynamic light scattering. These results showed that microemulsion made of 1% TTO, 9% Triton CG-110/PPG (1.8:1 w/w) was insensitive with time and temperature of storage. 相似文献
3.
Hybrid Silsesquioxane/Benzoate Cu7-Complexes: Synthesis,Unique Cage Structure,and Catalytic Activity
Alexey N. Bilyachenko Victor N. Khrustalev Evgenii I. Gutsul Anna Y. Zueva Alexander A. Korlyukov Lidia S. Shulpina Nikolay S. Ikonnikov Pavel V. Dorovatovskii Dmitri Gelman Elena S. Shubina Georgiy B. Shulpin 《Molecules (Basel, Switzerland)》2022,27(23)
A series of phenylsilsesquioxane-benzoate heptacopper complexes 1–3 were synthesized and characterized by X-ray crystallography. Two parallel routes of toluene spontaneous oxidation (into benzyl alcohol and benzoate) assisted the formation of the cagelike structure 1. A unique multi-ligation of copper ions (from (i) silsesquioxane, (ii) benzoate, (iii) benzyl alcohol, (iv) pyridine, (v) dimethyl-formamide and (vi) water ligands) was found in 1. Directed self-assembly using benzoic acid as a reactant afforded complexes 2–3 with the same main structural features as for 1, namely heptanuclear core coordinated by (i) two distorted pentameric cyclic silsesquioxane and (ii) four benzoate ligands, but featuring other solvate surroundings. Complex 3 was evaluated as a catalyst for the oxidation of alkanes to alkyl hydroperoxides and alcohols to ketones with hydrogen peroxide and tert-butyl hydroperoxide, respectively, at 50 °C in acetonitrile. The maximum yield of cyclohexane oxidation products as high as 32% was attained. The oxidation reaction results in a mixture of cyclohexyl hydroperoxide, cyclohexanol, and cyclohexanone. Upon the addition of triphenylphosphine, the cyclohexyl hydroperoxide is completely converted to cyclohexanol. The specific regio- and chemoselectivity in the oxidation of n-heptane and methylcyclohexane, respectively, indicate the involvement of of hydroxyl radicals. Complex 3 exhibits a high activity in the oxidation of alcohols. 相似文献
4.
The phospholipid (PL), cardiolipin (CL), is found almost exclusively in the inner membrane of mitochondria and loss of CL is considered as an important indication of cell apoptosis. Previously, 10-N-nonyl acridine orange (NAO) has been used as a fluorescent probe for the visualization of CL in mitochondrial cell membranes and in solution. In this work for the determination of CL, we have synthesized two new fluorescent probes, n-tetradecyl acridine orange (C14-AO), and n-octadecyl acridine orange (C18-AO) by reacting acridine orange with the corresponding n-alkyl bromide. Using excitation and emission wavelengths at about 500 and 525 nm and varying the percentage of methanol in water as the solvent, no interaction between CL and the fluorescent probes at 75% is noted but a proportional quenching of the fluorescence signal by CL is observed at 50% or less for C14-AO and 60% or less for C18-AO. Binding efficiency of these fluorescent probes to CL is compared using dye concentrations of 5, 10, and 20 μM. C18-AO shows a better sensitivity than C14-AO and NAO, respectively, but is less selective. For C14-AO, the detection limit and limit of quantitation are 0.07 and 0.21 μM, respectively, which are better than those previously reported for NAO. One anionic PL, phosphatidic acid, shows some quenching interference to both the C14 and C18 dyes but only at concentrations above the working range for sample analysis. The CL in mitochondrial membrane samples is determined by standard addition using C14-AO. The level of CL in the outer mitochondrial membrane compared to the inner membrane is significantly increased due to the addition of cadmium chloride into the cells causing cell apoptosis. 相似文献
5.
Matthias Linnert 《Journal of organometallic chemistry》2006,691(11):2358-2367
Sulfones RCH(R′)SO2Ph were reacted with n-BuLi in thf/n-hexane (R/R′ = H/Me, Me/Et, H/CH2Ph) and toluene/n-hexane (R/R′ = Me/Ph) yielding under deprotonation Li[CR(R′)SO2Ph] which reacted with Me3SiCl and n-Bu3SnCl forming the requisite trimethylsilyl and tri(n-butyl)tin substituted derivatives . Performing the reactions of RCH(R′)SO2Ph with n-BuLi in n-hexane (instead of thf/n-hexane) and toluene/n-hexane, respectively, resulted in the precipitation of the organo lithium compounds Li[CR(R′)SO2Ph] (1-4) which were isolated as strongly moisture-sensitive yellow powders in essentially quantitative yields. Their identities were confirmed by 1H and 13C NMR spectroscopic measurements in thf-d8. Solutions of each 1, 3, and 4 in thf/n-hexane and thf/n-pentane afforded crystals of each [{Li{CH(Me)SO2Ph}(thf)}∞] (1a), [{Li{CH(CH2Ph)SO2Ph}(thf)}∞] (3a), and [{Li{CMe(Ph)SO2Ph}(thf)2}2] (4a), respectively, whose structures were determined by single-crystal X-ray crystallography. The compounds 1a and 3a crystallize in 1D polymeric ladder-like structures. The strands of 1a are built-up by eight-membered Li2C2S2O2 rings having direct Li-C bonding interactions (Li-C 2.215(5) Å). The donor set of Li is completed by three oxygen atoms, one from the thf ligand and two from SO2 groups of neighboring Li{CH(Me)SO2Ph}(thf) entities. The strands of 3a are built-up of alternating Li2S2O4 eight- and Li2O2 four-membered rings. Each lithium atom is coordinated to three oxygen atoms, two from O2S(Ph)CHCH2Ph groups and one from thf oxygen atom. There is no Li-C bonding. Compound 4a crystallizes in dimers consisting of eight-membered Li2S2O4 rings in which the two lithium atoms are bridged by two O2S(Ph)CHMePh groups. The coordination sphere of lithium is completed by two oxygen atoms of the thf ligands. 相似文献
6.
José Roberto Tozoni Teresa Dib Zambon Atvars Leni Akcelrud Tito José Bonagamba 《European Polymer Journal》2009,45(8):2467-2477
A polyfluorene derivative of the PPV, poly(9,9′-n-dihexyl-2,7-fluorenedilvinylene-alt-1,4-phenylenevinylene), with a strong tendency to aggregation was blended with several members of a series composed by poly(alkyl methacrylate)s with the following substituents in the ester position: methyl, ethyl, isopropyl, isobutyl, n-butyl, and cyclohexyl. The de-aggregation effect in blends was studied by steady-state photoluminescence spectroscopy using several blend compositions. The efficiency of each dispersing phase was discussed in terms of the polymer miscibility, controlled by interaction parameters between the polyfluorene and every poly(alkyl methacrylate)s, here described using Hildebrand solubility parameters. 相似文献
7.
Sulfated tungstate catalyzed environmentally benign, simple, one pot, and solvent-free method has been developed for the synthesis of 1,3,5-triarylbenzenes via cyclic self-condensation of three molecules of aryl ketones. High yields, short reaction time, easy work-up procedure and recycling of the catalyst endorse advantage. 相似文献
8.
The electrophilic addition of bromine to an exocyclic diene, 5,6-dimethylenebicyclo[2.2.1]hept-2-ene, in CCl4 at 0°C led to the formation of non-rearranged (73%) and rearranged products (27%). However, high temperature bromination of the exocyclic diene at 77°C suppressed the formation of the rearranged products. Similarly, bromination of 9,10-dimethylenetricyclo[6.2.1.02,7]undeca-2,4,6-triene at −10°C gave only the exo-1,2-addition product. Bromination at +5°C resulted in the formation of a mixture consisting of exo-1,2- and 1,4-addition products in a ratio of (1:4). High temperature bromination at 77°C resulted in the formation of the endo-1,2-addition product. Furthermore, it has been shown that the 1,4-addition product converts smoothly to the 1,2-addition product. The formation mechanism of the products is discussed and supported by calculations. 相似文献
9.
Kui Mei Songtao He Mei Jin Guangshun Luo Lirong Song Wei Wang 《Tetrahedron letters》2008,49(17):2681-2684
A (S)-pyrrolidine sulfonamide catalyzed asymmetric direct aldol reaction of aryl methyl ketones with aromatic aldehydes has been developed with moderate to good enantioselectivities. The study considerably broadens the substrate scope of chiral amines promoted aldol processes. 相似文献
10.
Christina M. Brammell Chun-Hsing Chen Wei Weng Oleg V. Ozerov 《Journal of organometallic chemistry》2011,696(25):4132-4137
The diarylamido-based PNP pincer ligand can be used successfully for support of organometallic Hf complexes (PNP = [(4-Me-2-iPr2P-C6H3)2N]). (PNP)HfCl3 (3) was prepared via reaction of (PNP)Li (2) with HfCl4(OEt2). Reactions of (PNP)HfCl3 with alkyl Grignards led to triple alkylation to produce (PNP)HfMe3 (4) with a small methyl or only double alkylation to give (PNP)Hf(CH2SiMe3)2Cl (5) with a larger alkyl. Structures of 3, 4, and 5 in the solid state were established by X-ray diffraction studies. Structures of the alkyl complexes 4 and 5 display remarkably irregular coordination environments about Hf, while in 3 it is approximately octahedral. Compound 4 was found to be thermally stable at 75 °C. On the other hand, thermolysis of 5 at similar conditions led to a mixture of products, the major one of which is believed to be a Hf alkylidene on the basis of in situ NMR spectroscopic observations (e.g., δ 248.2 ppm in the 13C{1H} NMR spectrum). 相似文献
11.
Nabil Bensabeh Ana Jimnez-Alesanco Ilme Liblikas Juan C. Ronda Virginia Cdiz Marina Gali Lauri Vares Olga Abin Gerard Lligadas 《Molecules (Basel, Switzerland)》2020,25(23)
Lactic acid is one of the key biobased chemical building blocks, given its readily availability from sugars through fermentation and facile conversion into a range of important chemical intermediates and polymers. Herein, well-defined rubbery polymers derived from butyl lactate solvent were successfully prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization of the corresponding monomeric acrylic derivative. Good control over molecular weight and molecular weight distribution was achieved in bulk using either monofunctional or bifunctional trithiocarbonate-type chain transfer agents. Subsequently, poly(butyl lactate acrylate), with a relative low Tg (−20 °C), good thermal stability (5% wt. loss at 340 °C) and low toxicity was evaluated as a sustainable middle block in all-acrylic ABA copolymers using isosorbide and vanillin-derived glassy polyacrylates as representative end blocks. Thermal, morphological and mechanical properties of copolymers containing hard segment contents of <20 wt% were evaluated to demonstrate the suitability of rubbery poly(alkyl lactate) building blocks for developing functional sustainable materials. Noteworthy, 180° peel adhesion measurements showed that the synthesized biosourced all-acrylic ABA copolymers possess competitive performance when compared with commercial pressure-sensitive tapes. 相似文献
12.
A new homogeneous fluoroimmunoassay method based on the use of dynamic long-wavelength fluorescence polarization is presented here for the first time. This methodology, which is applied to the determination of linear alkylbenzenesulfonates (LASs) in water samples, involves the use of a new long-wavelength tracer synthesized from the oxazine dye Nile Blue (NB) via a carbodiimide method. This tracer exhibits fluorescent properties at λex 626 and λem 674 nm. The variation of fluorescence polarization with time is followed using the T-format configuration of the spectrofluorimeter and the analytical parameter used is the initial rate, which is measured in only 0.7 s. The dynamic range of the calibration graph is 0.05-4.7 mg/L, with a detection limit of 0.03 mg/L. The precision, expressed as relative standard deviation was assayed at 0.05 and 1 mg/L, giving values in the range 7.6-9.1%. Other anionic, cationic and non-ionic surfactants were tolerated at much higher concentration levels than that of the analyte. The method has proven its practical usefulness for the analysis of water samples, in which only a solid phase extraction step is necessary. Recoveries ranged from 80.8 to 119.8%, with a mean value of 100.8%. 相似文献
13.
Three-dimensional liquid crystal (LC) phases, cubic LC phases, have been extensively studied as fascinating molecular assembled systems formed by amphiphilic compounds. However, similar structures have only been seen in rare instances in lipid crystal states in glycolipid crystal studies. In this study, we prepared short-chain n-alkyl β-D-glucosides (CnG) with an alkyl chain length n ranging from 4 to 6 and investigated their crystal structures. First, differential thermal analysis (DTA) and thermogravimetric analysis (TG) measurements showed the formation of hydrated crystals for C4G and C5G, respectively. Second, the crystal structures of CnG (n = 4, 5, 6) in both anhydrous and hydrated states were examined using a temperature-controlled powder X-ray diffraction (PXRD) measurement. Both hydrate and anhydrous crystals of C4G and C5G with critical packing parameters (CPPs) less than 0.33 formed cubic crystal phases. Bilayer lengths, calculated from the main diffraction peaks in each PXRD profile, depended on crystalline moisture for C5G, but no significant change was confirmed for C4G, indicating that the properties of each hydrophilic layer differ. However, C6G with a CPP of 0.42 formed a crystal structure with a modulated lamellar structure similar to C7G and C8G with similar CPP values. Thus, a glycolipid motif concept with a cubic crystal structure was demonstrated. 相似文献
14.
Perfluoro oxymethylene vinyl ethers have been formed by a multi-step synthesis. The key intermediates are low molecular weight perfluoropolyether (PFPE) fluoroformates CF3O(CF2O)nCOF (I) n=1-6 obtained from the photo-oxidation of perfluoro propene (HFP) in perfluorohexane. Under certain conditions the light-mediated fluorination of PFPE fluoroformates (I) gives PFPE hypofluorites CF3O(CF2O)nCF2OF (II), which can be added to sym dichlorodifluoroethene to form the dichloro adduct CF3O(CF2O)nCF2OCFClCF2Cl (III) which, after dechlorination, gives the desired vinyl ethers CF3O(CF2O)nCF2OCFCF2 (IV). Every reaction step has to be properly controlled as far as the reaction variables are concerned. A mechanistic scheme is presented that is consistent with the observed experimental data. 相似文献
15.
A novel one-pot protocol for the preparation of cycloalkano[1,2-a]indoles by way of an intramolecular alkyl migration reaction in cyclic indolylborates is described. NaOMe was found to act as a successful trialkylboryl-protecting group against to the lithiation at the C2 of the indole ring. Treatment of cyclic indolylborates with electrophiles produced cycloalkano-[1,2-a]indoles. 相似文献
16.
Tania R van den Ancker Lutz M Engelhardt Geraldine E Jacobsen Brian W Skelton 《Journal of organometallic chemistry》2004,689(11):1991-1999
The reaction of MCl2 (M=Zn, Cd and Hg) with Li(2-(C(SiMe3)2)(6-Me-C5H3N)), [Li(MeR)], affords mononuclear metal(II) alkyls. These, in the solid state, show intramolecular M-N interactions in their four-membered chelate rings, which progressively weaken down the series, the C-M-C angles becoming more open (〈M-N〉= 2.30(2), 2.52(2), 2.913(4) Å, C-M-C=160.7(2), 168.5(2), 180(-)°). Alkylmercury chloride complexes have been prepared by the reaction of HgCl2 with [Li(MeR)], Li(2-(C(SiMe3)2)(C5H4N)), [Li(HR)], or Li(2-(NSiMe3)(6-Me-C5H3N)), [Li(mpsa)], or from the redistribution reaction of the dialkyl (or amido) mercury complex with HgCl2. The alkylmercury chloride complexes are dimeric or polymeric in nature with near-linear 2-coordination; (Hg-Cl=2.329(5), 2.318(4), 2.272(8) Å, Cl-Hg-C(N)=175.0(4), 174.7(4), 175.6(5)°). Cd(2-(CH(SiMe3))(6-Me-C5H3N))2(tmen), prepared from the reaction of Li(2-(CH(SiMe3))(6-Me-C5H3N)) and CdCl2 in the presence of tmen, has also been structurally authenticated as the rac isomer with the ipso protons directed towards the tmen. 相似文献
17.
Alexander V. Orlinkov 《Tetrahedron letters》2010,51(2):259-263
Selective one-pot functionalization of linear alkyl acetates CnH2n + 1OCOMe (n = 6, 8), with CO and various nucleophilic substrates (iso-propanol, morpholine, piperidine, and anisole) in the presence of the superelectrophilic system CBr4·2AlBr3 is performed for the first time. 相似文献
18.
Oiazoacetateisaversatilereagentinorganicsynthesis'.Ithasbeenwidelyusedincyclopropanation.etheration.elc.Bothenantiomericselectivityanddiastereoselectivit}ofcyclopropanationaregreatlyaffectedbyalkylgroupofalkyldiazoacetate.Highselectivitieswereobtainedusingstericdemandingdiazoacetate.Aratallihasusedmenth}'jdiazoacetate(MnDA)=.andDoylehasemployed2.6-di-lerl-butyl-4meth\lphenyldiazoacetate3toachievehighselectivities.Masamunefoundthatdicyclohexylmethyldiazoacetate(DCHMDA)wassuperiortotheabove… 相似文献
19.
Mpelegeng Victoria Bvumbi Chris van der Westhuyzen Edwin M. Mmutlane Andile Ngwane 《Molecules (Basel, Switzerland)》2021,26(14)
A series of novel riminophenazine derivatives, having ionizable alkyl substituents at N-5 and a variety of substituents on the C-3 imino nitrogen, at C-8 and on the pendant aryl group, have been designed and synthesized. Preliminary investigations into the relationship between lipophilicity, redox potential, and antimycobacterial activity were conducted, using the in vitro activity against Mycobacterium tuberculosis H37Rv, mammalian cytotoxicity, and the redox potential of the compounds determined by cyclic voltammetry as measures. Results revealed an activity “cliff” associated with C-8 substitution (10l and 10m) that, along with defined redox activity, point to a new class of riminophenazines as potential anti-tuberculosis agents having reasonable activity (MIC99 ~1 µM). 相似文献
20.
Jens Christoffers Thomas Werner Angelika Baro Peter Fischer 《Journal of organometallic chemistry》2004,689(22):3550-3555
A 3-tert-butyl-1-(stannylpropyl)-functionalized cyclopentadienyl ligand precursor 6 is readily available in 64% overall yield from allylic alcohol 1 by a three-step reaction sequence including Pd-catalyzed hydrostannylation with Ph3SnH. Treatment with FeCl2 and ZrCl4 · 2THF afforded corresponding ferrocene and zirconocene derivatives. Transmetallation of Sn-Ph with Li-Bu was observed under these reaction conditions by using BuLi as a base. 相似文献