with benzoquinones have been studied by spectrophotometry and steady state and transient fluorescent methods. TTPa forms a 1:1 molecular complex with 1,4-benzoquinone, 2,3,5,6-tetramethyl 1,4-benzoquinone and 2,3,5,6-tetrachloro 1,4-benzoquinone in dimethyl sulfoxide at room temperature. The equilibrium constants for the interaction of TTPa with the different quinones were evaluated. 相似文献
A new polyacrylonitrile fiber‐supported Brønsted acid catalyst has been developed and verified to efficiently (high yield, 10 cycles) mediate Biginelli reactions in ethanol, Pechmann condensations in toluene, Friedel–Crafts alkylations of indoles in water and conversion of fructose in dimethyl sulfoxide (DMSO) and mixed‐aqueous system.
Summary Ten new alternating, either 11 or 12, copolymers of electrophilic trisubstituted ethylenes with electron-rich vinyl monomers, were synthesized by free radical copolymerization.Thanks are also due to Dr. Anne Padias and Mr. Ashish Pandya of these Laboratories for the new synthesis of dimethyl cyanofumarate. 相似文献
Ethyl ester hydrochloride of amino acid l-methionine 1 was converted to cationic monomers N,N-diallyl methionine ethyl ester hydrochloride 2 and hydrochloride salt of N,N-diallylmethionine 3. Cationic monomers 2 and 3 underwent alternate copolymerization with SO2 in dimethyl sulfoxide to give terpolymers 4 and 5, respectively, both having?≈?1:1 ratio of sulfide and sulfoxide motifs owing to O transfer from dimethyl sulfoxide to the S. The sulfide groups in 5 have been oxidized with H2O2 to give polymer sulfoxide 6. In the presence of a small concentration of 35.2 µM (~?11?±?1 ppm) of each of the polymers 4, 5 and 6, the inhibition efficiency against mild steel corrosion in 1.0 M HCl at 60 °C was determined to be 90.8, 98.7 and 93.0%, respectively. The inhibition efficiency obtained from gravimetric weight loss was corroborated by the findings of potentiodynamic polarization and electrochemical impedance spectroscopy methods. Adsorption of polymer compounds onto the mild steel surface followed a mixture of chemisorption and physisorption processes and obeyed Langmuir, Temkin and Freundlich adsorption isotherms. The X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy techniques further confirmed that the synthesized compounds formed a protective film onto the metal surface and prove it against further corrosion attack. 相似文献
The condensation of pyrrolyl-2-aldehyde or 1-methyl-pyrrolyl-2-aldehyde with dimethyl succinate, using sodium hydride as condensing agent, gave predominantly the halfesters 1a and 1c respectively. Their structure and (E)-configuration
1 i. e., pyrrol ring and COOCH3 group are in trans position. This nomenclature follows the IUPAC 1968 Tentative Rules, Section E, Fundamental Stereochemistry, J. org. Chemistry 35 , 2849 (1970).
were confirmed by their cyclisation to the corresponding indole derivatives 2a–h . 相似文献
An expedient cleavage of the C S bond of dimethyl sulfoxide (DMSO) has been developed for the preparation of substituted pyridines from ketones. In this transformation, the co‐product formic acid was formed from ammonium formate, which acted as an important catalyst for the reaction. Notably, this transformation exhibited a broad substrate scope towards a wide variety of different ketones to give the corresponding substituted pyridines in high yields. Mechanistic studies suggested that dimethyl sulfoxide delivered a methylene fragment, which was subsequently captured in situ to give a pyridine.
This study describes the synthesis, crystal structure, porosity, and thermal stability of a new three-dimensional nano-porous metal-organic framework, [Ce2(tp)3(DMF)2(DMSO)2]n, 1, (H2tp = terephthalic acid, DMF = dimethyl formamid, DMSO = dimethyl sulfoxide). Compound 1 was synthesized by the solvothermal reaction of Ce(NO3)3·6H2O and H2tp and was then characterized by single-crystal X-ray diffraction and infrared spectroscopy. Structural analysis of 1 showed that Ce(III) ion has coordination number nine in a distorted mono-capped square anti-prismatic geometry. Gas sorption studies revealed a relatively reversible type-I isotherm characteristic of a porous material with surface area, pore volume, and average pore size of 179.4 m2 g?1, 0.73 cm3 g?1, and 3.8 Å, respectively. 相似文献
The complexes (PPh4)2[MoVIO2(NCS)4] (1), MoVIO2(NCS)2(di-tBu-bipy) (2) and Mo2VIO5(NCS)2(di-tBu-bipy)2 (3) (di-tBu-bipy = 4,4′-di-tert-butyl-2,2′-bipyridine) were studied as catalyst precursors for the oxidation of cyclooctene (Cy8) and benzyl alcohol (BzOH), using either dimethyl sulfoxide (DMSO) or tert-butyl hydroperoxide (TBHP) as oxidant. By dissolving complex 2 in the room temperature ionic liquid 1-butyl-3-methylpyridinium tetrafluoroborate, the catalytic performance with TBHP was improved (higher selectivity to the aldehyde and higher Cy8 conversions). For Cy8 oxidation, the unreacted substrate and products were easily extracted with n-hexane, and the ionic phase containing the catalyst could be reused without loss of catalytic performance. 相似文献
A bifunctional comonomer β-methylhydrogen itaconate was synthesized to prepare high molecular weight poly [acrylonitrile-co-(β-methylhydrogen itaconate)] [P (AN-co-MHI)] by mixed solvents polymerization, which was used as carbon fiber precursor instead of acrylonitrile terpolymers. The effect of dimethyl sulfoxide (DMSO)/deionized water ratios on the polymerization, structure and stabilization of P (AN-co-MHI) was studied by elemental analysis, UV-Visible Spectroscopy, fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The highest viscosity-average molecular weight (76.72 × 104 g/mol) of P(AN-co-MHI) was obtained in the mixed solvents of DMSO/deionized water = 10/90 (wt/wt) due to the zero chain transfer constant of deionized water for radical ~ ~ ~AN·, which is 10 times larger than that of P(AN-co-MHI) copolymers prepared in DMSO solution polymerization under the same conditions and is beneficial to improving the tensile strength of resulting carbon fiber. The composition of P(AN-co-MHI) was controlled by the ratio of DMSO/deionized water in the mixed solvents, it is attributed to the changes of AN/MHI ratio taking part in the polymerization reactions, which is caused by the different solubility of AN in the mixed solvents. From elemental analysis and FTIR studies, it can be found out that the content of MHI in P(AN-co-MHI) copolymer becomes larger with the increase of DMSO content in the mixed solvents. The FTIR, XRD and DSC results show that the stabilization of P(AN-co-MHI) copolymer was significantly improved by MHI compared with PAN homopolymer and poly (acrlonitrile-methyl acrylate-acrylic acid) terpolymer, such as larger extent of stabilization, lower initiation temperature and smaller Ea of cyclization, which is beneficial to preparing high performance carbon fiber. 相似文献
The electrochemiluminescence (ECL) behavior of luminol in oxygen-saturated dimethyl sulfoxide (DMSO) solution at a polycrystalline gold electrode was studied under conventional cyclic voltammetric (CV) conditions. Corresponding to the reduction processes of oxygen, one ECL peak (ECL-1 at −1.40 V versus SCE) with two shoulders (S1-1 at −0.55 V and S1-2 at −0.90 V) was observed on the curve of ECL intensity versus potential. Corresponding to the subsequent oxidation processes of oxygen-containing species generated by the reduction of oxygen, one ECL peak (ECL-2 at −0.34 V) with a shoulder (S2 at −0.67 V) was found. Among them, ECL-2 was strongest; it was 10 times stronger than ECL in pH 13.0 aqueous alkaline solution under the same conditions. These ECL peaks and shoulders were found to depend on the presence of N2 and O2, potential scan range, water concentration, supporting electrolyte, and the concentration of luminol. The emitter of both ECL peaks was identified as 3-aminophthalate (AP2−) by analyzing the ECL spectra. The origin for these ECL peaks is proposed to be related to the reactions of luminol with various oxygen-containing species such as O2−, H2O2, OH− and O2 electrogenerated by the redox reactions of dissolved oxygen at different potentials. The results indicate that the ECL of luminol was correlated to the redox behavior of oxygen in DMSO. The present work reveals that the solvent plays an important role in the ECL behavior of luminol. 相似文献
Phosphorylation of poly(N-vinyl pyrrolidone-co-vinyl amine) and poly(N-vinyl pyrrolidone-co-glycidylcrotonate
1 Systematic name: (2,3-Epoxypropyl)crotonate.
) is realized by Atherton-Todd and Fields-Kabachnik reactions and by the means of direct interaction with phosphorus trichloride and phosphorus trichloride oxide. The composition and structure of the isolated final products was proved by NMR (1H and 31P), IR spectroscopy and elemental analysis. 相似文献
The one‐pot synthesis of substituted 2‐arylquinazoline derivatives and tetracylic isoindolo[1,2‐a]quinazoline via cyanation followed by rearrangement of ortho‐substituted 2‐halo‐N‐arylbenzamides is described. Using dimethyl sulfoxide (DMSO) as the solvent, the cleavage of the tetracyclic isoindole fused quinazoline leads to the formation of 2‐arylquinazoline derivatives. When 1,4‐dioxane is used as the solvent, tetracyclic isoindole fused quinazolines are produced in good yield. A wide range of products, including 2‐phenylquinazolin‐4‐amine, 4‐methyl‐2‐phenylquinazoline and long‐chain 2‐phenyl‐4‐styrylquinazoline derivatives were produced in moderate to good yields using DMSO as the solvent. However, various tetracyclic isoindole fused quinazoline derivatives were obtained in good yields when 1,4‐dioxane was used as the solvent.
Potassium hydroxide (KOH) in dimethyl sulfoxide (DMSO) forms a superbasic medium that allows one to access cross‐coupling products from reactions between aryl halides with various sulfur‐, oxygen‐ and nitrogen‐based nucleophiles under transition metal‐free conditions. 相似文献
Anodic oxidation of dimethyl sulfoxide (DMSO) based electrolyte solutions, containing LiClO4, LiBF4 and KPF6, on platinum (Pt), glassy carbon (GC) andn-TiO2 (anatase), electrodes was studied usingin situ Fourier transform infrared spectroscopy (FTIR). All solutions contained small amounts of H2O. Regardless of the supporting electrolyte all systems were unstable at potentials above 1.0 V vs SCE. The major oxidation product is dimethyl sulfone, formation of which is initiated by the trace water breakdown. In contrast to acetonitrile based solutions there is no evidence of electrolyte involvement in the breakdown process. Photoanodic decomposition of dimethyl sulfoxide based solutions proceeds in the same way as the anodic oxidation in the dark. In the presence of nucleophilic agent (iodides) the prevailing redox process is iodide oxidation. Small amounts of, probably, methylsulfinyliodide are also formed. The irreversible consumption of charge mediator significantly restricts the possible practical use of DMSO in photoelectrochemical devices. 相似文献
The direct α‐Csp2 H functionalization and thiomethylation of α‐oxoketene dithioacetals (DTAs) has been accomplished with dimethyl sulfoxide (DMSO) in the presence of iodine and a copper(I) salt for the first time. A prerequisite is the in situ iodination of the α‐Csp2 atom of dithioacetals that could offer other reaction channels. The operationally simple one‐pot protocol includes region‐defined consecutive iodination and sulfenylation of the challenging α‐Csp2 H bond of dithioacetals employing cheap and readily available reagents. DMSO here plays a dual role as thiomethyl source and solvent.
Two organic solvent systems containing equimolar ratio of water but different association strenght, 8/2 by wt mixture of dimethyl sulfoxide (DMSO) and water and 86.7/13.3 by wt mixture of N-methyl morpholine N-oxide and water (NMMO monohydrate), were chosen and the rheological properties of polyvinyl alcohol (PVA) solutions in the solvents were investigated and compared. The associated state of water in the solvent systems had a significant effect on the rheological properties of the solutions. In dilute concentration regime, NMMO monohydrate gave higher intrinsic viscosity than DMSO/water although two solvents gave similar values of the Mark-Houwink exponent. More noticeable difference was observed on the viscosity curve in high concentration regime. DMSO/water exhibited near a Bingham behavior and gave much lower power-law index than NMMO monohydrate. On the logarithmic plot of storage modulus (G′) against loss modulus (G″), both solutions exhibited slight decrease in slope with increasing concentration. Of two solvent systems DMSO/water gave lower values of slope than NMMO monohydrate. In addition, NMMO monohydrate gave greater than one at low frequency whereas DMSO/water gave much less than one over the entire frequency range examined. Further, the frequency to cause gelation was decreased with increasing concentration in the case of NMMO monohydrate. This indicates that PVA/DMSO/water system is more heterogeneous because weakly bonded water molecules produce hydrogel structure. 相似文献