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.     

Phenol-formaldehyde resin route to the synthesis of several iron group transition metal phosphides

Abstract

A series of iron, cobalt and nickel metal phosphides of chemical formula Fe_xP, Co₂P and Ni₂P with high specific surface areas of 331.1, 294.2 and 228.0 m² g^?1, respectively, was firstly synthesized by phenol-formaldehyde resin route. It was found that the as-prepared Co₂P and Ni₂P samples synthesized using phenol-formaldehyde resin as a carbon source showed much higher BET surface areas than those prepared using other carbon sources reported before, including cinnamic strong alkali anion exchange resin, p-phenylenediamine and hexamethylenetetramine. This phenol-formaldehyde resin route was proved to be as universal as traditional H₂ reduction method.     

Synthesis,polymerization, and thermal properties of benzoxazine based on bisphenol‐S and allylamine

A bifunctional benzoxazine monomer, 6,6′‐bis(3‐allyl‐3,4‐dihydro‐2H‐benzo[e][1,3]oxazinyl) sulfone (BS‐ala), was synthesized from bisphenol‐S, allylamine and formaldehyde via a solution method. The chemical structure of BS‐ala was confirmed by ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and elemental analysis. The polymerization behavior of BS‐ala was investigated by FTIR, solid‐state ¹³C NMR, and differential scanning calorimetry (DSC). The oxazine ring opening polymerization is prior to the addition polymerization of allyl group, and the exothermic peaks corresponding to the two reactions appear partially overlapped in the DSC curve. The storage modulus of the resultant polybenzoxazine at 25°C is about 3.9 GPa, and the glass transition temperature is 254°C. The 5% and 10% weight loss temperatures of the polybenzoxazine are about 335°C and 361°C in both air and nitrogen, respectively. The char yield is about 58% at 800°C in nitrogen, whereas almost no residue is remained at 700°C in air. Copyright © 2012 John Wiley & Sons, Ltd.     

Dissociations of Complexes Between Monovalent Metal Ions and Aromatic Amino Acid or Histidine

The fragmentations of [AA + M]⁺ complexes, where AA = Phe, Tyr, Trp, or His, and M is a monovalent metal (Li, Na, or Ag), have been exhaustively studied through collision-induced dissociation (CID) and through deuterium labeling. Dissociations of the Li- and Ag-containing complexes gave a large number of fragment ions; by contrast, the sodium/amino acid complexes have lower binding energies, and dissociation resulted in much simpler spectra, with loss of the entire ligand dominating. Unambiguous assignments of these fragment ions were made and formation mechanisms are proposed. Of particular interest are fragmentations in which the charge was retained on the organic fragment and the metal was lost, either as a metal hydride (AgH) or hydroxide (LiOH) or as the silver atom (Ag^?).

Synthesis of Stimuli-responsive Nanoparticles by Solution Polymerization

In this study, stimuli-responsive nanoparticles were prepared by solution polymerization. Two synthesis routes are proposed to synthesize the particles, the monomer route and the polymer/monomer route. For the monomer route, pH and thermal sensitive nanoparticles were synthesized from acrylic acid and N-isopropylacrylamide. For the polymer/monomer route, the pH sensitive nanoparticles were synthesized from chitosan and acrylic acid. The effect of reaction time, initiator concentration and agitation rate on the particle size and the size distribution were investigated. The stimuli-responsive nanoparticles could be directly blended with other polymers to prepare stimuli-responsive functional membranes.     

Synthesis and Properties of Poly(Aryl Ether Ketone) Copolymers with Trifluoromethyl‐Substituted Benzene in the Side Chain

The new monomer (4‐(4′‐trifluoromethyl)phenoxyphenyl)hydroquinone (TFPOPH) was synthesized in a three‐step synthesis. A series of poly(aryl ether ketone) copolymers were prepared by the reaction of (4‐(4′‐Trifluoromethyl)phenoxyphenyl)hydroquinone and hydroquinone (HQ) with 4,4′‐difluorobenzophenone (DFB) in the presence of potassium carbonate in tretramethylene sulfone (TMS). Thermal analyses of the fluorinated copolymers showed that the glass transition temperature and 5.0% weight loss temperature are similar with that of PEEK, and the crystallinity decreased with increasing of TFPOPH. For the copolymer synthesized with the molar fraction of TFPOPH in the diphenol monomers (TFPOPH, HQ) being over 0.2, no cold crystallization temperature and melting temperature were detected, indicating that these copolymers are almost amorphous. The crystal structure of the copolymers with the molar fraction of TFPOPH being not higher than 0.2 is rhombic. The solubility in polar aprotic solvents of poly(aryl ether ketone)s copolymers increases and dielectric constant decreases step by step.     

Chitooligosaccharide Copolymers: Synthesis and Aqueous Self-assembly

Novel water-soluble amphiphilic graft copolymers (COS-g-PCL-b-MPEG) were synthesized by the coupling reaction between chitooligosaccharide (COS) and MPEG-b-PCL-COOH, which was synthesized via ring-opening polymerization of ε-caprolactone (CL) using MPEG as an initiator and subsequent carboxylation by succinic anhydride. The chemical composition of the graft copolymers was confirmed by ¹H-NMR spectra and FT-IR spectrometry. The thermal properties and crystallinity of the copolymers were observed by DSC and XRD measurements, which showed the existence of separate backbone and graft chain phases in the copolymer. The micellar behavior via self-assembly of the graft copolymers in aqueous solution was studied using pyrene fluorescence dye technique. AFM measurements showed that the micelles had a spherical morphology at the critical micelle concentration (CMC) and ranged in size from 20–45 nm. The amphiphilic ternary biodegradable graft copolymer endows the hydrophilic outer shell of micelles with structural and functional diversification, which might be desirable for drug delivery applications.     

Preparation and Surface Properties of Fluorine‐Containing Diblock Copolymers PLMA‐Block‐PFAEA

A series of fluorine‐containing diblock copolymers based on lauryl methacrylate and 1H,1H,2H,2H‐perfluoroalkyl acrylate have been prepared by atom transfer radical polymerization (ATRP). The preparation process of PLMA‐Br macroinitiators was controlled within a reasonable time corresponding to the ln [M₀]/[M_t]～time plot of the reaction. FTIR, ¹H‐NMR, GPC and fluorine‐element analysis (FEA) were used to characterize the synthesized block copolymers. The solid surface activity of these polymers was demonstrated by contact angle measurement. The polymer films prepared by block copolymers with more than three fluorinated units showed low dispersion force contributions to the surface energy indicating the presence of the fluorinated block at the surface. The surface activity in solutions was measured by drop‐weight method. Ii is interesting to find, when the fluorine weight percentage is controlled constant, that PLMA‐b‐PFAEA with larger molecular size is more prominent in exploiting the fluorinated structure to reduce the surface tension of solutions. The block copolymer's ability in reducing surface tension of solutions also depends on the type of solvent.     

Simultaneous determination of thirteen main components and identification of eight major metabolites in Xuebijing Injection by UPLC/Q-TOF

An ultra performance liquid chromatographic method was used for the simultaneous identification and quantification of thirteen main components in Xuebijing Injection, including uridine, gallic acid, guanosine, danshensu, protocatechualdehyde, oxypaeoniflorin, hydroxysafflor yellow A, paeoniflorin, ferulic acid, safflor yellow A, senkyunolide I, senkyunolide H and salvianolic acid B. The chromatographic separation was performed on an Acquity UPLC BEH C₁₈ column (1.7-μm, 2.1 × 100 mm, i.d.) with a gradient elution of acetonitrile and 0.2% acetic acid at a flow rate of 0.4 mL/min. The method was validated for linearity (r ² > 0.9990), intra- and inter-day precision (RSD < 1.94%), accuracy (91.8–99.7%), recovery (96.8–103.8%), limits of detection (0.16–8.0 ng), and limits of quantification (0.54–26.8 ng). At least eight metabolites in prototype were found in rat plasma and urine after intravenous injection of 4 mL/kg doses of Xuebijing Injection. The proposed method could be utilized to qualify and control Xuebijing Injection to ensure its safety and efficacy in application.