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1.
1,3-diphenyl-1H-pyrazole-4-carboxaldehyde (1) reacted with ethyl cyanoacetate and thiourea to give the pyrimidinethione derivative 2. The reaction of 2 with some alkylating agents gave the corresponding thioethers 3a–e and 7. Thione 2 was cyclized to 5 and 6 upon a reaction with chloroacetic acid and with benzaldehyde, respectively. Thioether 3c was cyclized to 4 upon boiling with sodium acetate in ethanol, and 7 was cyclized to 8 upon boiling in an acetic anhydride-pyridine mixture. The hydrazino derivative 9 was prepared either by boiling 2 and/or 3a with hydrazine. The reaction of 9 with nitrous acid, acetylacetone, triethyl orthoformate, acetic anhydride, and carbon disulfide gave 10–14. The alkylation of 14 with ethyl iodide, phenacyl bromide, and ethyl chloroacetate afforded the alkythiotriazolo pyrimidinone derivatives 15a–c. The dialkyl derivative 16 was produced upon the treatment of 2 with two equivalents of ethyl iodide. Boiling 16 with hydrazine afforded the hydrazino 17. The reaction of 17 with nitrous acid, carbon disulfide, ethyl cyanoacetate, ethyl acetoacetae, and phenacyl bromide gave 18–22, respectively. Some of the newly obtained compounds were tested for their antibacterial and antifungal activities.  相似文献   

2.
Abstract

3,4-Diamino-2,5-dicarbethoxythieno(2.3-b)thiophene 1 reacted with malononitrile or ethyl cyanoacetate to afford bis(thienopyrimidin-4-one) derivatives 2a.b The reaction of compound 1 with o-aminothiophenol, o-aminophenol or o-phenylenediamine gave benzothiazolyl-, benzoxazolyl-, benzoimidazolylthienothiophene 3a-c, Chloroacetylation of compound 1 and reacting the resulting compound 4 with malononitrile furnished thienopyrolopyrimidine 6. Fusion of compound 1 with formamide yielded bis(thienopyrimidine) 7 which reacted with POCI3/PCl5 to yield the corresponding chloro derivative 8 which was converted into the corresponding hydrazine derivative 9. Treatment of compound 1 with CS2, NaOH and 1,2 dibromoethane produced the corresponding 1.3 dithiolane 11 which also treated with chloroacetyl chloride or ethyl mercaptoacetate to get the corresponding β-lactame 12 or thiazolidinone 13. On reacting compound 1 with CS2, NaOH and (CH3)2S04 produced the corresponding bi(dithiocarbamate methyl ester) 14 which treated with hydrazine hydrate to yield the corresponding bis(thienopyrimidine) derivative 15. This compound reacted with Lawesson's reagent (LR) to give the desired compounds 16 and 17. While its reaction with (CH3)2 SO4 and NaOH furnished the corresponding methyl derivative 18. Fusion of compound 18 with aniline afforded compound 19. Compound 19 was allowed to react with ethyl acetoacetate, acetylacetone, α-oxoketene dithioacetal, ethoxymethylene malononitrile or LR to get the described compounds 2Oa.b-24 respectively.  相似文献   

3.
N-Cyanomethyl and N-propargyl β-amino alcohols are chlorinated with SOCl2 and treated with NaN3 in DMSO. A substitution/cycloaddition process affords in good yields, with high diastereoselectivity and a regioselectivity depending on the substitution pattern of the starting amino alcohol, fused tri- and tetrazoles-piperazines. These heterocycles were further lithiated with n-BuLi at the benzylic position and reacted diastereoselectively with a range of electrophiles.  相似文献   

4.
Fullerene hydrides containing 24–26 H atoms per fullerene molecule were obtained by hydrogenation of solid-phase mixtures of fullerenes with either intermetallic compounds LaNi5, LaNi4.65Mn0.35, CeCo3 or V and Pd metals with gaseous hydrogen at 1.0–2.5 MPa and 573–673 K. These fullerene hydrides decompose at 800 K with evolution of H2. Upon subsequent heating to 1000 K, vanadium reacts with fullerene to yield a cubic phase of vanadium carbide. The intermetallic compounds react with fullerene with the formation of a metallic phase of the 3d-metal and destruction of fullerene. Palladium does not react with fullerene. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 679–683, April, 1997.  相似文献   

5.
Esters of cellulose with trifluoroethoxy acetic acid (TFAA) were prepared in homogeneous phase using a mixed anhydride with p‐toluenesulfonic acid. Esters with low degree of substitution (DS), and with DS rising from 0 to 3, had hydrophobic character that prevented the usual association with moisture, which is otherwise typical of cellulose esters with low DS. Cellulose trifluoroethoxy acetate (CT) had Tg's declining by about 40 °C per DS‐unit (from 160 to 41 °C) as DS rose from 1 to 3. Mixed esters, cellulose derivatives with acetate and trifluoroethoxy acetate substituents (CAT), exhibited glass‐to‐rubber and melting transitions by DSC. A linear relationship between both Tg and Tm with respect to DS was recorded with the Tg and Tm separated by 30° to 40 °C. This is consistent with cellulose esters described elsewhere. Surprisingly, the Tg's of CT and CAT were found to be identical when the DS was equivalent to the DS of the fluoro substituents (DSF). © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 486–494, 2000  相似文献   

6.
We investigated the catalytic performance of both bridged unsubstituted [rac‐EtInd2ZrMe2, rac‐Me2SiInd2ZrMe2] and 2‐substituted [rac‐Et(2‐MeInd)2ZrMe2), rac‐Me2Si(2‐MeInd)2ZrMe2] dimethylbisindenylzirconocenes activated with triisobutyl aluminum (TIBA) as a single activator in (a) homopolymerizations of ethylene and propylene, (b) copolymerization of ethylene with propylene and hexene‐1, and (c) copolymerization of propylene with hexene‐1 (at AlTIBA/Zr = 100‐300 mol/mol). Unsubstituted catalysts were inactive in homopolymerizations of ethylene and propylene and copolymerization of propylene with hexene‐1 but exhibited high activity in copolymerizations of ethylene with propylene and hexene‐1. 2‐Substituted zirconocenes activated with TIBA were active in homopolymerizations of ethylene and propylene and exhibited high activity in copolymerization of ethylene with propylene and hexene‐1, and in copolymerization of propylene with hexene‐1. Comparative microstructural analysis of ethylene‐propylene copolymers prepared over rac‐Me2SiInd2ZrMe2 activated with TIBA or Me2NHPhB(C6F5)4 has shown that the copolymers formed upon activation with TIBA are statistical in nature with some tendency to alternation, whereas those with borate activated system show a tendency to formation of comonomer blocks. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2934–2941, 2010  相似文献   

7.
Copolyamides 1,9 , and 10 containing both cyclobutane rings and conjugated double bonds in the main chain were synthesized by polycondensation of 1,3-di(4-piperidyl)propane (DPP) with β-truxinate (β-BNPT), with di(p-nitrophenyl) p-phenylenebis(acrylate) (p-NPDA), with di(p-nitrophenyl) p-phenylenebis (α-cyanoacrylate) (p-NPDC), and with di(p-nitrophenyl) p-phenylenebis (α-cyanobutadienecarboxylate) (p-NPDCB) in aprotic polar solvents at room temperature, respectively. Reduced viscosity of copolyamide 1 was strongly affected by the reaction process, the molar ratio of two ester monomers, and reaction time. The copolyamide 1 with the highest viscosity was prepared by the reaction of DPP with 70–50 mol % of β-BNPT for 24 h followed by the polycondensation of the resulting precursor with 30–50 mol % of p-NPDA for 24–96 h. Although copolyamide 9 with high viscosity was not obtained by the polycondensation with β-BNPT and p-NPDC, copolyamide 10 with relatively high viscosity was obtained by the reaction with β-BNPT and p-NPDCB under the same conditions applied for the synthesis of copolyamide 1 . The solubility of copolyamides 1,9 , and 10 decreased gradually with increasing p-NPDA, p-NPDC, and p-NPDCB units in the copolymers. Furthermore, it was found that copolyamides 1,9 , and 10 crosslinked upon irradiation with 313 or 365 nm light, and these copolyamides also decomposed upon irradiation with 254 nm light. That is, the photochemical property of these copolyamides can be controlled by the selection of wavelength of the photoirradiation.  相似文献   

8.
《Analytical letters》2012,45(3):315-321
Abstract

A high-performance liquid chromatography assay was developed for the purpose of examining xanthine, hypoxanthine, uridine, thymidine, allopurinol, and oxypurinol in serum of patients with advanced carcinoma treated with methorexate and 5-fluorouracil. After the addition of an internal standard, serum samples were extracted of purines and pyrimidines with trichloroacetic acid and neutralized with tert-amine. Aliquots of the extracted serum were injected onto a C18 reverse-phase column and purines and pyrimidines were eluted with a gradient of MeOH/H2O and KH2PO4 solutions. Absorbance was detected with a variable-wavelength UV spectrophotometer at 254 nm and 280 nm. This assay can be readily applied to quantitate baseline and treatment-induced variations in serum purine and pyrimidine levels which may correlate with clinical response and/or toxicity in patients with cancer.  相似文献   

9.
Virajkumar Gandhi 《Tetrahedron》2010,66(10):1787-14551
Porphyrins with fused pyrene units have been prepared by ‘2+2’ and ‘3+1’ methodologies. Nitration of 1,2,3,6,7,8-tetrahydropyrene, followed by oxidation with DDQ, gave 4-nitropyrene and this condensed with ethyl isocyanoacetate in the presence of DBU or a phosphazene base to generate a pyrenopyrrole ethyl ester. Ester saponification and decarboxylation with KOH in ethylene glycol at 190 °C gave the parent pyreno[4,5-c]pyrrole and this was further condensed with 2 equiv of acetoxymethylpyrroles to afford the corresponding tripyrranes protected at the terminal positions with tert-butyl esters. In a one pot procedure, the ester protective groups were cleaved with TFA and following dilution with dichloromethane, ‘3+1’ condensation with a pyrrole dialdehyde, and dehydrogenation with DDQ, the targeted pyrenoporphyrins were generated in good overall yields. A dialdehyde was also prepared from the pyrenopyrrole intermediate and this reacted to give an opp-dipyrenoporphyrin. The pyrenopyrrole ethyl ester reacted with dimethoxymethane in the presence of an acid catalyst to give a dipyrenopyrrolylmethane, and this was used to prepare an adj-dipyrenoporphyrin using the MacDonald ‘2+2’ approach. The pyrenopyrrole dialdehyde was also used to prepare a porphyrin with fused pyrene and phenanthroline moieties. Although the UV-vis spectra of these new porphyrin systems are unexceptional, pyrenoporphyrins show many of the features necessary for the construction of porphyrin molecular wires.  相似文献   

10.
Chelating resins with thioglycolate anchor groups have been synthesized by reaction of sucrosemethacrylate gels with thioglycolic acid. The capacities of the gels were found to be extremely high for Ag+ (5,3 mmol/g) and Hg2+ (4,9 mmol/g). About 1 mmol Hg2+/g could be recovered from the gel reversibly by treatment with hydrochloric acid. The removal of Hg2+ from aqueous 3M alkalichloride solutions was possible with capacities of 1 mmol/g.Sucrosemethacrylate gels with primary aromatic amino group were reacted with CS2/NH3 to yield gels with dithiocarbamate groups. Gels with thiorea groups were prepared by reaction of the amino groups with NH4SCN/HCl. Diazotation of the amino groups, subsequent reaction with potassium xanthogenate and hydrolysis afforded gels with thiol groups. Thiol containing gels were synthesized also by reaction of the diazotised gels with Na2S2 and subsequent reduction with Na2S. Reaction of the diazotised gels with mercaptans yielded resins with thioether anchor groups. The capacities of the sulfur containing gels were found to be max. 4,1 mmol/g for Hg2+ and 5,9 mmol/g for Ag+. About 35% of the bonded Hg2+ could be eluted resersibly with 3N-HCl.
  相似文献   

11.
3-Bromoacetyl-1,5-diphenyl-1H-pyrazole-4-carbonitrile (1) reacts with sodium benzenesulfinate to give the corresponding ketosulfone 2. Treatment of 2 with hydrazonoyl chlorides 3a,b gives the 3,3′-bipyrazoles 5a,b. Ketosulfone 2 reacts also with arylidenemalononitriles to give the pyrazolylpyridones 10a,b. The reaction of compound 2 with phenylisothiocyanate and potassium hydroxide and treating intermediate with hydrazonoyl halides and with α-haloketones gives the 1,3,4-thiadiazoles 18a–c and thiophenes 21a–f, respectively.  相似文献   

12.
Polydimethylsiloxane (PDMS) block copolymers were synthesized by using PDMS macroinitiators with copper-mediated living radical polymerization. Diamino PDMS led to initiators that gave ABA block copolymers, but there was low initiator efficiency and molecular weights are somewhat uncontrolled. The use of mono- and difunctional carbinol–hydroxyl functional initiators led to AB and ABA block copolymers with narrow polydispersity indices (PDIs) and controlled number-average molecular weights (Mn's). Polymerization with methyl methacrylate (MMA) and 2-dimethylaminoethyl methacrylate (DMAEMA) was discovered with a range of molecular weights produced. Polymerizations proceeded with excellent first-order kinetics indicative of living polymerization. ABA block copolymers with MMA were prepared with between 28 and 84 wt % poly(methyl methacrylate) with Mn's between 7.6 and 35 K (PDI <1.30), which show thermal transitions characteristic of block copolymers. ABA block copolymers with DMAEMA led to amphiphilic block copolymers with Mn's between 9.5 and 45.7 K (PDIs of 1.25–1.70), which formed aggregates in solution with a critical micelle concentration of 0.1 g dm−3 as determined by pyrene fluorimetry experiments. Monocarbinol functional PDMS gave AB block copolymers with both MMA and DMAEMA. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1833–1842, 2001  相似文献   

13.
A pressure-controlled scanning calorimeter (PCSC) has been applied for measuring the isobaric volume thermal expansivities (αp) of crystalline polymers as a function of pressure up to 300 MPa at various temperatures. The measurements have been performed for several well-defined polyethylenes with various degrees of crystallinity at 302.6, 333.0, 362.6, and 393.0 K. The results are reported as values of coefficients in a correlation equation, which facilitates the use of reported data over large ranges of temperature and pressure. The general pressure-temperature behavior of αp for all polyethylenes under study is such that αp increases with temperature and decreases with pressure. The increase with temperature is smaller at high pressures and the isotherms of αp have a tendency to converge at high pressures; αp decreases linearly with the crystallinity of the polyethylene over the whole range of pressure and temperature under investigation. From the linear approximation of experimental data for polyethylenes with various crystallinities the estimated αp for both crystal and amorphous phases of polyethylenes have been determined as a function of pressure up to 300 MPa at 302.6, 333.0, and 362.5 K. The obtained results have been compared with available literature crystallographic data and with the values derived from the Pastine theoretical equation of state for both crystalline and amorphous phases. © 1996 John Wiley & Sons, Inc.  相似文献   

14.
New p-tert-butylthiacalix[4]arenes with several different substituents at the lower rim have been synthesised. A method for the selective introduction of one or two guanidinium fragments into the structure of p-tert-butylthiacalix[4]arenes has been developed. The 1,3-alternate thiacalix[4]arenes containing guanidinium groups interact with silver nitrate and oxalic acid in methanol with a logKassoc of about 3.5 and 1:1 stoichiometry, while the macrocycle in the cone conformation interacts with oxalic acid with logKassoc of 7.4 and 2:1 stoichiometry. The new p-tert-butylthiacalix[4]arenes form nanoscale aggregates with hydrodynamic radii of about 70 nm by self-association and by mediation with silver cations and oxalic acid.  相似文献   

15.

Pyridopyrimidine derivatives 2 reacted with hydrazonoylchloride derivatives and yielded triazolopyridopyrimidines 6a–f. Compound 4b reacted with aliphatic acids and afforded triazolo-pyridopyrimidines 7a,b, and the reaction with carbon disulfide afforded 10-mercapto-triazolopyridopyrimidine (10). Moreover, the reaction of 4b with β -ketoesters afforded 10-pyrazolyl-pyridopyrimidines derivatives 11, 13, 14, and 15. Compound 4b reacted with nitrous acid to give tetrazolopyridopyrimidine 16, which reduced to 10-amino-derivative 17. On the other hand, the reaction of 4b with aromatic aldehydes afforded arylidines derivatives 18a–c, which were later cyclized to triazolo-pyridopyrimidines deivatives 19a–c. Finally, 4b reacted with α-haloketones to give triazines derivativrs 20, with new ring systems.  相似文献   

16.
A practical investigation of frictional heating effects in conventional C18 columns was undertaken, to investigate whether problems found for sub-2 μm columns were also present for those of particle size 3 μm and 5 μm and different internal diameter. The influence of a water bath, a still air heater, and a forced air heater on performance was investigated. Heating effects were substantial, with a decrease in k of almost 15% for toluene over the flow rate range ∼0.4–2.3 mL/min with a 15 cm × 0.46 cm ID column packed with 3 μm particles. Heating effects on retention increased with increasing solute k, with increase in the column ID, with decrease in the column particle size, and with decrease in the set column oven temperature. While the water bath minimised axial temperature gradients and thus its effect on k, radial temperature gradients were potentially serious with this system, especially at high mobile phase velocity, even with columns containing 5 μm particles. In contrast to the effects of axial temperature gradients in 4.6 mm columns, very little difference in Van Deemter plots was noted between the three different thermostats with 2 mm ID columns, even when 3 μm particles were used. However, the efficiency of 2 mm columns for peaks of low or moderate k (k < 4) can be compromised by the extra dead volume introduced by the heating systems, even with conventional HPLC systems with otherwise minimised extra column volume.  相似文献   

17.
Two new classes of mono- and oligo(p-phenylene ethynylene)s grafted with polyhedral oligomeric silsesquioxanes (POSS) were synthesized via ‘click’ chemistry and palladium-catalyzed Sonogashira cross-coupling. These materials with cubic silsesquioxanes are very robust with excellent thermal stability in air (T5%loss>330 °C) and exhibited Tg>80 °C. All the compounds showed high photoluminescence with a range of blue emission and quantum yield up to 80% in the solution. Extended π conjugation molecules of oligo-pPEs POSS maintain relatively high PL quantum efficiencies in the solid state, compared to mono-pPEs POSS. A preliminary report is made of some of the materials as multilayer OLED components with active dopants PVK and PBD.  相似文献   

18.
Using the Picker flow microcalorimeter, excess heat capacities have been obtained at 25°C throughout the concentration range for 2,2-dimethylbutane,n-hexane, and cyclohexane each mixed with a series of hexadecane isomers of increasing degrees of orientational order, as determined by depolarized Rayleigh scattering. The isomers are 2,2,4,4,6,8,8-heptamethylnonane, 6-, 4-, and 2-methylpentadecane, andn-hexadecane. Thec p E values are negative, increasing rapidly in magnitude with increase of orientational order, and are not predicted by the Prigogine—Flory theory which neglects order. Values ofc p E are obtained at 10, 25, and 55°C for cyclohexane +6-, 4-, and 2-methylpentadecane which with other literature data lead to the temperature dependence of the thermodynamic excess functions for cyclohexane solutions of the five C16 isomers. The excess enthalpy and entropy vary with the C16 isomer and with temperature, but the corresponding variation of the excess free energy is small, indicating a high degree of enthalpy-entropy compensation. This is consistent with a rapid decrease with temperature of orientational order in the C16 isomers.  相似文献   

19.
Reactions of peroxyl radicals and peroxynitrite with o-vanillin (2-hydroxy 3-methoxy benzaldehyde), a positional isomer of the well-known dietary compound vanillin, were studied to understand the mechanisms of its free radical scavenging action. Trichloromethylperoxyl radicals (CCl3O 2 · ) were used as model peroxyl radicals and their reactions with o-vanillin were studied using nanosecond pulse radiolysis technique with absorption detection. The reaction produced a transient with a bimolecular rate constant of approx. 105 M−1s−1, having absorption in the 400–500 nm region with a maximum at 450 nm. This spectrum looked significantly different from that of phenoxyl radicals of o-vanillin produced by the one-electron oxidation by azide radicals. The spectra and decay kinetics suggest that peroxyl radical reacts with o-vanillin mainly by forming a radical adduct. Peroxynitrite reactions with o-vanillin at pH 6.8 were studied using a stopped-flow spectrophotometer. o-Vanillin reacts with peroxynitrite with a bimolecular rate constant of 3 × 103 M−1s−1. The reaction produced an intermediate having absorption in the wavelength region of 300–500 nm with a absorption maximum at 420 nm, that subsequently decayed in 20 s with a first-order decay constant of 0.09 s−1. The studies indicate that o-vanillin is a very efficient scavenger of peroxynitrite, but not a very good scavenger of peroxyl radical. The reactions take place through the aldehyde and the phenolic OH group and are significantly different from other phenolic compounds.  相似文献   

20.
Hydrolysis and polycondensation reactions of tetraethoxysilane (TEOS) with 3,3,3-trifluoropropyl-trimethoxysilane (TFMS) or 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFES) were used to synthesize xerogels functionalized with fluorine-containing groups. According to transmission electron microscopy, the skeletons of synthesized polysiloxane xerogels have globular structures and consist of agglomerates of particles with fluorinated groups on their surfaces. FTIR spectroscopy showed that primary xerogel particles possess spatial polysiloxane networks, with fluorinated groups along with silanol groups and water in the surface layer. According to thermal analyses, the water content was 3–8 wt.%, and it decreased with increasing length of the fluorinated chain. Thermal destruction of the surface layer starts above 300 °C. The sorbents that were obtained were predominantly mesoporous materials with well-developed porous structures (SBET = 400–960 m2 g−1, Vs = 0.66–0.93 cm3 g−1). The influence of the TEOS/functional silane ratio and the natures of the functional groups on the structural and adsorptive properties were shown. The samples synthesized are organophilic. The affinity for n-hexane increases with increasing length of the fluorine-containing chain (PFES) and the content of fluorinated groups in the surface layer. The hybrid organic–inorganic materials that were obtained can be used for adsorption of hydrocarbons, including oil, from water.  相似文献   

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