Synthesis and characterization of flavylium salts having three types color depending on recrystallization conditions

Three types of flavylium salts (FVs, yellow, green and red) have been synthesized and the colors depended on recrystallization conditions. The existence of these color states was confirmed by diffuse reflectance spectra. The spectra were almost the same as the absorption spectra in ethanol solution. The molecular state of FVs in crystals will be the same as that in solutions. The crystal colors of the FVs are controlled by the recrystallization conditions.     

Why do flavylium salts show so various colors in solution?: Effect of concentration and water on the flavylium’s color changes

When synthesized flavylium salts (FVs) were allowed to stand in an acetonitrile–water mixture, the color of the solutions changed from yellow to red via green. This color change in FV solution has been studied by observing the change in UV–VIS absorption spectra. In particular, change in the color from green to red depends on the concentration of FV and an amount of water. The solution color, however, changed from red to green on dehydration of the solution. It is concluded that water molecules are responsible for the change in solution color from green to red and the change is due to dimerization and/or aggregation of FVs.     

Preparation and characterization of three types of cefquinome-loaded microspheres

The polymers of poly (lactic-co-glycolic acid), gelatin, and ethyl cellulose were used to control the microscopic structure of microspheres prepared by spray drying. We investigated controlled release by varying material concentrations, sprayer inlet temperatures and air velocities, and optimized process parameters of yield, particle size, and distribution. Three types of polymeric microspheres with a mean particle size range of 13–25?µm were loaded with cefquinome and characterized. In vitro drug release studies determined that microspheres were the most suitable structures for controlling release due to their high entrapment capacities and release times greater than 24?h.     

Synthesis and characterization of two charge-transfer salts based on Keggin-type polyoxometalates and morpholinebiguanide

Two new inorganic-organic salts, formulated as (C₆H₁₃N₅OH)₂ [HPMo₁₂O₄₀] · 5H₂O and (C₆H₁₃N₅OH)₃[PW₁₂O₄₀], were synthesized and characterized by elemental analysis, IR, ESR, diffuse reflectance spectra, thermogravimetry, and X-ray photoelectron spectroscopy. Solid diffuse reflectance spectra showed charge-transfer interactions between the inorganic and organic moieties in the solid state. Salt I had strong photosensitivity for UV light or X-ray irradiation, and its photochromic reaction under UV light was found to exhibit first-order kinetics. The article is published in the original.     

二甲基烯丙基胺/溴代烷烃系列季铵盐的合成与表征

以溴代烷与二甲基烯丙基胺(DMAA)为原料合成了二甲基烯丙基类季铵盐;探讨了反应温度、原料配比、反应时间及溶剂对反应产率的影响,确定了最佳合成条件;并采用红外光谱仪、核磁共振谱仪(1 H NMR)及质谱仪表征了产物的结构.     

Performance comparison of three types of high-speed counter-current chromatographs for the separation of components of hydrophilic and hydrophobic color additives

The performance of three types of high-speed counter-current chromatography (HSCCC) instruments was assessed for their use in separating components in hydrophilic and hydrophobic dye mixtures. The HSCCC instruments compared were: (i) a J-type coil planet centrifuge (CPC) system with a conventional multilayer-coil column, (ii) a J-type CPC system with a spiral-tube assembly-coil column, and (iii) a cross-axis CPC system with a multilayer-coil column. The hydrophilic dye mixture consisted of a sample of FD&C Blue No. 2 that contained mainly two isomeric components, 5,5'- and 5,7'-disulfonated indigo, in the ratio of ～7:1. The hydrophobic dye mixture consisted of a sample of D&C Red No. 17 (mainly Sudan III) and Sudan II in the ratio of ～4:1. The two-phase solvent systems used for these separations were 1-butanol/1.3M HCl and hexane/acetonitrile. Each of the three instruments was used in two experiments for the hydrophilic dye mixture and two for the hydrophobic dye mixture, for a total of 12 experiments. In one set of experiments, the lower phase was used as the mobile phase, and in the second set of experiments, the upper phase was used as the mobile phase. The results suggest that: (a) use of a J-type instrument with either a multilayer-coil column or a spiral-tube assembly column, applying the lower phase as the mobile phase, is preferable for separating the hydrophilic components of FD&C Blue No. 2; and (b) use of a J-type instrument with multilayer-coil column, while applying either the upper phase or the lower phase as the mobile phase, is preferable for separating the hydrophobic dye mixture of D&C Red No. 17 and Sudan II.     

Synthesis and antiproliferative evaluation of bis-styrylbenzothiazol-3-ium salts

A series of bis-styrylbenzothiazol-3-ium salts containing different substituents 4–12 were synthesized from 2-methylbenzothiazole by condensation of quaternary salts 1–3 with p-substituted benzaldehydes. All compounds were characterized by IR, ¹H and ¹³C NMR, MS, and elemental analysis. Synthesized compounds 4–12 were screened for antitumor activities. Based on presented in vitro screening results we may conclude that compounds 4–6 and 9 showed the best cell growth inhibitory activity. Correspondence: Grace Karminski-Zamola, Department of Organic Chemistry, Faculty of Chemical Engineering and Technology, Marulićev trg 20, HR-10000 Zagreb, Croatia.     

Reaction of N-acylthioureas with electrophilic reagents : Synthesis of 1,3,5-oxadiazinium salts, 1,3,5-thiadiazinium salts, 1,2,4-dithiazolium salts and benzothiazoles

N-Acylthioureas 1 can be easily transformed into 2,4-diamino-6-aryl-1,3,5-oxadiazinium salts 12, 2,4-diamino-6-aryl-1,3,5-thiadiazinium salts 13,3-amino-5-aryl-1,2,4-dithiazolium salts 19 and 2-acylimino-benzothiazolines 22, respectively by reaction with different electrophiles. The structure of the compounds prepared is confirmed by analytical data as well as by chemical transformations.     

Synthesis and characterization of perfluorinated nitriles and the corresponding sodium 5-perfluoroalkyltetrazolate salts

The high-yield syntheses of trifluoroacetonitrile (1a), pentafluoropropionitrile (1b) and heptafluorobutyronitrile (1c) under mild reaction conditions using readily available starting materials (trifluoroacetamide, pentafluoropropionamide, heptafluorobutanamide) are described. Furthermore, the reactions of the perfluoroalkyl nitriles with sodium azide in acetonitrile forming sodium 5-trifluoromethyltetrazolate (2a), sodium 5-pentafluoroethyltetrazolate (2b) and sodium 5-heptafluoropropyltetrazolate (2c) were undertaken. The 5-perfluoroalkyltetrazolate salts were characterized using vibrational (Raman and infrared) and multinuclear (¹³C, ^14/15N, ¹⁹F) NMR spectroscopy, differential scanning calorimetry, mass spectrometry and elemental analysis. Additionally, the single crystal X-ray structure of the monohydrate of 2a was determined. Crystal data: 2a·H₂O: monoclinic, C2/m, a = 18.8588(6) Å, b = 7.1857(2) Å, c = 9.3731(3) Å, β = 102.938(3)°, V = 1237.94(7) Å³, Z = 8, D_calc = 1.911 g cm⁻³.     

Synthesis and characterization of polysilabutane having oligo(oxyethylene)phenyl groups on the silicon atom

A new class of polar polysilabutanes with mono- or tri-(oxyethylene)phenyl groups on the silicon atom have been synthesized by anionic polymerization of silacyclobutanes having ω-(t-butyldimethylsilyl-protected) mono- or tri-(oxyethylene)phenyl groups and subsequent deprotection of the silyl groups. The monomers were synthesized by treatment of 1,1-dichlorosilacyclobutane with ω-(t-butyldimethylsilyl-protected) mono- or tri-(oxyethylene)phenyl Grignard reagents. Anionic polymerization of silacyclobutane was performed with butyllithium initiator in THF. t-Butyldimethylsilyl-protecting groups at polymer pendant groups were hydrolyzed with tetrabutyl ammonium fluoride in water-containing THF. The obtained polysilabutanes were soluble in a polar organic solvent such as methanol, and their mass distributions were analysed by matrix-assisted laser-desorption-ionization mass spectrometry (MALDI TOF MS). © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 225–231, 1998     

Synthesis and characterization of three new thermally stable N-heterocyclic germylenes

Three new stable germylenes, rac-1,3-di-tert-butyl-4,5-dimethyl-1,3-diaza-2-germacyclopentane-2-ylide (1), 1,3-di-tert-butyl-4,4-dimethyl-1,3-diaza-2-germacyclopentane-2-ylide (2), and rac-1,3,4-tri-tert-butyl-1,3-diaza-2-germacyclopentane-2-ylide (3) have been synthesized by the reaction of their corresponding germyl dichlorides with elemental lithium. Full synthetic procedures and characterizations are described.     

Synthesis and characterization of copolymers based on benzothiadizole-thiophene-phenylenevinylene

<正>Two novel copolymers based on benzothiadizole-thiophene-phenylenevinylene have been synthesized through palladium catalyzed triple-bond polycondensation method.The copolymers exhibit good solubility in common organic solvents such as CHCl_3,CH_2Cl_2 and THF.The structures and properties of the two copolymers are characterized by FT-IR, ~1H-NMR,UV-Vis absorbance(Abs),gel permeation chromatography(GPC),thermal gravimetric analysis and cyclic voltammetry(CV).The copolymers of P_1 and P_2 show absorption spectra with maximum peak at 532 nm and 573 nm in solution,respectively.Compare to their monomers M_1 and M_2,the absorption peaks of P_1 and P_2 were red-shifted by 34 nm and 54 nm respectively.Thermal gravimetric analysis demonstrated that the polymers were stable and little weight loss was observed below 300℃.Cyclic voltammetry experiments showed that the band gaps of the copolymers were 1.81 eV and 1.62 eV,respectively,suggesting their potential for applications as organic solar cell materials.     

Synthesis and characterization of soluble conjugated polymers having pyrene moiety in the main chain

Three new alternating conjugated polymers consisting of pyrene and 3‐dodecylthiophene ( PPyMT ), 4,4′‐didodecyl‐2,2′‐bithiophene ( PPyBT ), or 9,9‐didodecylfluorene ( PPyFlu ) moieties have been prepared using Suzuki coupling reaction or Sugimoto approaches. The polymers were readily soluble in common organic solvents and exhibited good thermal stability in nitrogen and air atmospheres. The structures and optical properties of the polymers were characterized by NMR, FTIR, XRD, UV–vis, and fluorescence spectroscopy. PPyMT and PPYBT showed blue‐light emission in solution, whereas PPyFlu performed blue‐light emitting in film state. The polymers exhibited an intermolecular aggregation and structural ordering due to pyrene–pyrene π–π stacking interaction. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Synthesis, characterization and photocrosslinking properties of polyacrylamides having bromo substituted pendant cinnamoyl moieties

New 3- and 4-bromocinnamoyl aniline were synthesized condensing 4-aminoacetophenone and the respective bromobenzaldehydes in the presence of sodium hydroxide. The monomers, 4-(3′-bromocinnamoyl) phenyl acrylamide (4,3′-BCPA) and 4-(4′-bromocinnamoyl) phenyl acrylamide (4,4′-BCPA) were prepared by reacting the respective chalcones and acryloyl chloride in the presence of triethylamine at 0-5 °C. Homopolymers of 4,3′-BCPA and 4,4′-BCPA was carried out in methyl ethyl ketone using benzoyl peroxide (BPO) under nitrogen atmosphere at 70 °C. The prepared polymers were characterized by UV, IR, ¹H-NMR and ¹³C-NMR techniques. The molecular weights (M_w and M_n) of the polymers were determined by gel permeation chromatography. The thermogravimetric analysis (TGA) of the polymers in nitrogen atmosphere reveals that they possess very good thermal stability required of a negative type photoresist. The glass transition temperature of poly(4,3′-BCPA) and poly (4,4′-BCPA) were found to be 55 and 64 °C respectively. The solubility of the polymers was tested in various polar and non-polar solvents. Photocrosslinking nature of the polymer samples was carried out in the presence and absence of various triplet photosensitizers in solution phase using chloroform solvent under medium frequency UV light. For using the polymers as negative photoresist materials the rate of photocrosslinking of the polymers was measured under the influence of different solvents, concentrations and position of the substituent.     

Synthesis and characterization of new poly(azomethine ester)s having phenylthiourea units

New polyesters having azomethine and phenylthiourea groups in the polymer backbone were synthesized by interfacial polycondensation method. The dihydroxy monomer N-(4-hydroxy-3-methoxybenzal) N′-(4′-hydroxyphenyl)thiourea was condensed with six diacid chlorides: terephthaloyl, isophthaloyl, azeloyl, suberoyl, pimeloyl and adipolyl chlorides. The resulting polyesters were characterized by viscosity, IR, NMR and TGA analysis. The wholly aromatic poly(azomethine ester) derived from terephthaloyl chloride when blended with polyaniline/NH₄OH, polyaniline/HCl and pure polyaniline shows conductance in the range 3.2 × 10⁻³-0.91 × 10⁻¹ S cm⁻¹.     

Synthesis of some novel tetraimidazolium salts derived from diphenyl- and dimethylglycolurils

Several new tetrabromo compounds based on diphenyl- and dimethylglycolurils were synthesized. Sequential treatment of these compounds with imidazole, methyl iodide, and sodium tetrafluoroborate gave their corresponding tetra imidazolium salts. Some of these compounds because of their low melting points can be registered as a potential and new class of ionic liquids. Correspondence: Mehdi Bakavoli, Department of Chemistry, School of Sciences, Ferdowsi University, Mashhad 91375-1436, Iran.     

聚天冬氨酸钙的合成与表征

螯合的有机酸钙,属于现今钙营养强化剂中的新一代产品[1]。这类钙剂进入血液不是立即解离成钙离子,而是持续离出钙离子供机体利用,从而避免血清中钙离子浓度过高出现高血钙,保证钙元素充分吸收和利用[2,3]。聚天冬氨酸钙具有多肽的化学结构,被人体吸收利用的速度相对要慢、代谢     

Synthesis, characterization and crystal structures of the tetrachlorocuprate and tetrabromocadmate salts of the antimalarial mefloquine

Two new compounds, bis (DL-erythro-α-2-piperydylium-2,8-bis(trifluoromethyl)-4-quinolinemethanol) tetrachlorocuprate(II) tetrahydrate [LH⁺]₂[CuCl₄]^2??4H₂O 1 [L = mefloquine] and bis(DL-erythro-α-2-piperydylium-2,8-bis(trifluoromethyl)-4-quinolinemethanol) tetrabromocadmate (II) bis(methanol) [LH⁺]₂[CdBr₄]^2?·2CH₃OH 2, have been synthesized and characterized by elemental analysis, ¹H-NMR and IR spectroscopy. Single-crystal X-ray diffraction analysis of 1 showed the structure to be ionic with formula unit comprising two protonated monocationic mefloquine molecules of opposite chirality, a tetrachlorocuprate (II) anion and a complement of four water molecules, disordered over several sites. The crystals are orthorhombic, space group Pnma, a = 9.6975(1) Å, b = 29.5385(3) Å, c = 15.9423(1) Å, V = 4566.67(7) ų, Z = 4. The formula unit of compound 2 comprises two protonated monocationic mefloquine molecules, a tetrabromocadmate(II) anion and two molecules of methanol. The crystals are orthorhombic, space group Fdd2, a = 17.2185(5) Å, b = 55.456(2) Å, c = 9.5140(3) Å, V = 9084.6(5) ų, Z = 8. The mefloquine molecule is protonated at the piperidinyl N atom and extensive hydrogen bonding occurs in both crystal structures. The conformation of the mefloquine cation in 1 and 2 is very similar to that recently observed in other salts of the drug, confirming its relevance in the context of antimalarial action.