The Reaction Activity of Aromatic Carbonyl Compounds with Diphenylphosphine Oxide Studied by 31P NMR

Abstract

A series of α-hydroxyphosphine oxides were prepared by the reactions of diphenylphosphine oxide and aromatic carbonyl compounds and characterized by ¹H NMR, ¹³C NMR, ³¹P NMR, FT-IR, ESI-MS, and HR-MS spectra. The reaction rates and experimental conditions of aromatic aldehydes and aromatic ketones were obviously different due to the activity of their carbonyls. The different substituents of the aromatic aldehydes affected the reaction rate too, and the quantitative reactivity of their substituent conformed to the Hammett equation. The results were confirmed by ³¹P NMR spectroscopy.     

The Investigation of Interaction Competition Between ATP and DIPP-Ala,Boc-Ala,or Ala by ESI-MS/MS and Theoretical Calculation

The interactions between ATP and N-(O,O-diisopropyl) phosphoryl-L-alanine (DIPP-Ala), N-(tert-butoxycarbonyl)-L-alanine (Boc-Ala), or L-alanine (Ala) were investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS). The non-covalent complexes between ATP and Boc-Ala or DIPP-Ala were observed, while the complex between ATP and Ala was not found in the mass spectra. The affinity of DIPP-Ala for ATP was confirmed to be stronger than that of Boc-Ala by competition experiment. Through molecular modeling calculations, it was found that the non-covalent complexes were stabilized by intermolecular hydrogen bonds, and the affinity sequence for ATP was DIPP-Ala > Boc-Ala > Ala by comparing their binding energy, ?35.407 kcal/mol, ?15.634 kcal/mol, ?6.555 kcal/mol, respectively. The results implied that a phosphoryl group was a very important functional group to provide an interaction site between amino acids and ATP, and that N-phosphoryl amino acids can be used as a good model of protein in the studies of molecular recognition of ATP.     

The Synthesis and 31P NMR Spectral Studies of Cyclophosphazenes

A modified method for preparing large-scale quantities of pure hexachlorocyclophosphazene (N₃P₃Cl₆) and octachlorocyclotetraphosphazene (N₄P₄Cl₈), phosphorus pentachloride with ammonium chloride, in the presence of zinc chloride, has been developed. The time of the reaction and the quantities of the catalyst are also studied. It is found that the optimum reaction time is 1.5 h and by-products are remarkably reduced by addition of 10% zinc chloride. As indicated by the ³¹ P NMR spectra, the synthesis and separation of cyclophosphazenes can be accomplished in moderate yield of tetramer (39%) and good yield of trimer (83%).     

Catalytic activity of chiral chelating N-heterocyclic carbene palladium complexes towards asymmetric allylic alkylation

Abstract

The catalytic activity of a series of chiral heteroaryl coordinated chelating N-heterocyclic carbene (NHC) palladium complexes towards asymmetric allylic alkylation (AAA) were presented here. The effects of different N-substituents, NHC backbones and chelate rings on the catalytic activity and the enantioselectivity of the alkylation of (E)-1,3-diarylallyl acetates with dialkyl malonate were investigated. The results showed that, under the optimized conditions, complexes 3a, 3b, and 3i carrying the pyridinyl-coordinated five-membered chelate ring showed high catalytic activity and chiral induction efficiency. The corresponding alkylated products were obtained in high yields with moderate ee. Furthermore, it was found that the substituents of (E)-1,3-diarylallyl acetates and the type of the nucleophile affect the results as well.     

Metal-free synthesis of (E)-vinyl sulfones via denitrative coupling reactions of β-nitrostyrenes with sodium sulfinates

Abstract

A practical metal-free procedure for the synthesis of (E)-vinyl sulfones has been developed through the coupling of β-nitrostyrenes with sodium sulfinates under microwave irradiation. This methodology provides a convenient and efficient approach to various (E)-vinyl sulfones from readily available starting materials with excellent regioselectivity. The present oxidative reaction involves an efficient denitrative radical cross-coupling of β-nitrostyrenes with sodium sulfinates via using AcOH as an additive.     

Synthesis and Characterization of Nitrogen Heterocyclic Derivatives Containing Sulfur–Ether and Schiff Base

Abstract

A series of new nitrogen heterocyclic compounds containing sulfur–ether (8a–8f) and Schiff-base (9a–9q) functionalities were synthesized by the reaction of the pharmaceutical lead compound containing both benzimidazole and 1,2,4-triazole rings. The compounds were characterized by ¹H NMR, ¹³C NMR, FT-IR, HR-MS, and ESI-MS.     

Synthesis and Characterization of Side Group-Modified Tetradentate Cyclotriphosphazene Derivatives

Abstract

A series of novel side group-modified cyclotriphosphazene derivatives were synthesized by the reaction of hexachlorocyclotriphosphazene [N₃P₃Cl₆] with 2,2′-diphenol and the potassium salt of 4-hydroxybenzaldehyde, and subsequent reduction of aldehyde groups to alcohol groups by the use of sodium borohydride. The bromination reaction was carried out with PBr₃ to give N₃P₃(O₂C₁₂H₈) (p-BrCH₂-C₆H₄-O-)₄. This compound was employed in reactions with macrocyclic polyamides, imidazole, or morpholine to produce title compounds. The target compounds were characterized by ¹H NMR, ³¹P NMR, ¹³C NMR, and electrospray ionization mass spectrometry.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Comments on stabilizing layered manganese oxide electrodes for Li batteries

An electrochemical study of structurally-integrated xLi₂MnO₃•(1 −x)LiMn_0.5Ni_0.5O₂ ‘composite’ materials has been undertaken to investigate the stability of electrochemically-activated electrodes at the Li₂MnO₃-rich end of the Li₂MnO₃–LiMn_0.5Ni_0.5O₂ tie-line, i.e., for 0.7 ≤ x ≤ 0.95. Excellent performance was observed for x = 0.7 in lithium half-cells; comparable to activated electrodes that have significantly lower values of x and are traditionally the preferred materials of choice. Electrodes with higher manganese content (x ≥ 0.8) showed significantly reduced performance. Implications for stabilizing low-cost, manganese-rich, layered lithium-metal-oxide electrode materials are discussed.     

Study on thermodynamic properties of glyphosate by oxygen-bomb calorimeter and DSC

The combustion enthalpy of glyphosate was determined by XRY-1C oxygen-bomb calorimeter at a constant volume. The standard mole combustion enthalpy and the standard mole formation enthalpy have been calculated to be ?1702.19 and ?1478.36 kJ mol^?1, respectively. For testing the reliability of instrument, glycine and naphthalene were used as reference materials by comparing the measured values with the literature values, the absolute error and relative error are 2.58 kJ mol^?1 and 0.26 % for glycine, respectively, and these of naphthalene are 4.08 kJ mol^?1 and 0.08 %, respectively. Moreover, the constant-pressure heat capacities c _p of glyphosate were measured by differential scanning calorimetry in the temperature range 303.15–365.15 K, and the relationship between c _p and temperature was established. These related studies can provide a thermodynamic basis for their further application.     

反应修饰剂ZnSO4和预处理对苯选择加氢制环己烯Ru-Zn催化剂性能的影响

共沉淀法制备了Ru-Zn催化剂,考察了反应修饰剂ZnSO₄和预处理对苯选择加氢制环己烯Ru-Zn催化剂性能的影响。结果表明,反应修饰剂ZnSO₄可以与Ru-Zn催化剂中助剂ZnO反应生成（Zn（OH）₂）₃（ZnSO₄）（H₂O）盐。随反应修饰剂ZnSO₄浓度增加,（Zn（OH）₂）₃（ZnSO₄）（H₂O）盐量的逐渐增加,Ru-Zn催化剂活性逐渐降低,环己烯选择性逐渐升高。因为（Zn（OH）₂）₃（ZnSO₄）（H₂O）盐中的Zn²⁺可以使Ru变为有利环己烯生成的缺电子的Ru^δ+物种,而且还可以占据不适宜环己烯生成的强Ru活性位。但当反应修饰剂ZnSO₄浓度高于0.41 mol·L^-1后,继续增加ZnSO₄浓度,由于Zn²⁺水解浆液酸性太强,可以溶解部分（Zn（OH）₂）₃（ZnSO₄）（H₂O）盐,Ru-Zn催化剂活性升高,环己烯选择性降低。但环己烯选择性却略微降低,这是由于ZnSO₄溶液中大量的Zn²⁺可以与生成的环己烯形成配合物,稳定生成的环己烯,抑制生成的环己烯再吸附到催化剂表面并加氢生成环己烷。在ZnSO₄最佳浓度0.61 mol·L^-1下对Ru-Zn催化剂预处理15 h,Ru-Zn催化剂中助剂ZnO可以与ZnSO₄完全反应生成（Zn（OH）₂）₃（ZnSO₄）（H₂O）盐,在该催化剂上25 min苯转化68.2%时环己烯选择性和收率分别为80.2%和54.7%。而且该催化剂具有良好的稳定性和重复使用性能。