Derivatives of 3-thienylphosphonic acid and 1,2-oxaphosphol-3-ene

Alkylsulfenyl chlorides react with 5-methyl-1,3,4-hexatrienyl-3-phosphonic esters giving derivatives of 3-thienylphosphonic acid and 1,2-oxaphosphol-3-ene.     

An RP-LC-UV-TWIMS-HRMS and Chemometric Approach to Differentiate between Momordica balsamina Chemotypes from Three Different Geographical Locations in Limpopo Province of South Africa

Momordica balsamina leaf extracts originating from three different geographical locations were analyzed using reversed-phase liquid chromatography (RP-LC) coupled to travelling wave ion mobility (TWIMS) and high-resolution mass spectrometry (HRMS) in conjunction with chemometric analysis to differentiate between potential chemotypes. Furthermore, the cytotoxicity of the three individual chemotypes was evaluated using HT-29 colon cancer cells. A total of 11 molecular species including three flavonol glycosides, five cucurbitane-type triterpenoid aglycones and three glycosidic cucurbitane-type triterpenoids were identified. The cucurbitane-type triterpenoid aglycones were detected in the positive ionization mode following dehydration [M + H − H₂O]⁺ of the parent compound, whereas the cucurbitane-type triterpenoid glycosides were primarily identified following adduct formation with ammonia [M + NH₄]⁺. The principle component analysis (PCA) loadings plot and a variable influence on projection (VIP) analysis revealed that the isomeric pair balsaminol E and/or karavilagen E was the key molecular species contributing to the distinction between geographical samples. Ultimately, based on statistical analysis, it is hypothesized that balsaminol E and/or karavilagen E are likely responsible for the cytotoxic effects in HT-29 cells.     

The Double Salts Cd(C6H5COO)2 · CdCl2 and Cd(C6H5COO)2 · CdBr2

The systems Cd(C₆H₅COO)₂ CdCl₂ H₂O and Cd(C₆H₅COO) ₂ CdBr₂ H₂O have been studied at 25 °C. Formation of the double salts Cd(C₆H₅COO)₂ · CdCl₂ and Cd(C₆H₅COO)₂ · CdBr₂(1:1:0) has been established and their chemical individuality has been confirmed by chemical, X-ray, and DT-analyses. Proceeding from data on the structure of Cd(C₆H₅COO)₂ · 2 H₂O and the composition of the 1:1:0 double salts as well as using Pauling's rules for the most probable spacial disposition of the ions, the crystal structure type of the double salts obtained are predicted.     

Double Salts Formation in the Systems MX–MeX 2–H2O (M=K,NH4, Rb,Cs; Me=Mg,Mn, Fe,Co, Ni,Cu; X=Cl,Br)

Monatshefte für Chemie - Chemical Monthly - ?The data available on the solubility phase diagrams and on the crystallization of chloride and bromide double salts in the systems...     

Effect of tetraalkylammonium salts on the tacticity of poly(methyl methacrylate), 1. Initiation by ethyl α-lithioisobutyrate

The anionic polymerization of methyl methacrylate (MMA) was carried out in the presence of ethyl α-lithioisobutyrate (α-LiEtIB)/quaternary ammonium salts (QAS) in toluene and tetrahydrofuran/toluene (vol. ratio 75/25) at −60°C. It was found that the tacticity of PMMA strongly depends on size and shape of QAS. A highly isotactic polymerization in toluene was observed, when using the system α-LiEtIB/trimethylhexadecylammonium bromide. The initiator system α-LiEtIB/tetrahexylammonium chloride produces polymers with a high (>50%) syndiotactic content and relatively low polydispersity. The influence of QAS on the mode of polymerization is due to specific salt effect resulting from the cation exchange reaction, from the participation of the bulky substituent in the primary solvation shell, and ionic aggregation between the growing anion, Q⁺ and LiX.     

Mixed block copolymer aggregates with tunable temperature behavior

A block copolymer of propylene oxide (PO) and ethoxyethyl glycidyl ether (EEGE), (PO)(2)(EEGE)(6)(PO)(2), that has been found to possess lower critical solution temperature properties in water in the temperature range below 20 degrees C was mixed at 1:0.1, 1:1, and 1:10 weight ratios with commercially available Pluronic (L64 or P85) block copolymers. The cooperative association of the copolymers in aqueous solution was studied by dynamic light scattering over a wide temperature range (5-60 degrees C). At lower temperatures, the systems containing either L64 or P85 behave similarly irrespective of the composition: three species corresponding to (PO)(2)(EEGE)(6)(PO)(2) unimers, Pluronic-dominated mixed micelles, and large (50-60 nm in radius) composite (PO)(2)(EEGE)(6)(PO)(2)/Pluronic aggregates were identified. At a certain temperature, which is composition-dependent, the systems phase-separate [(PO)(2)(EEGE)(6)(PO)(2)/L64 1:0.1], enter an interval of instability [(PO)(2)(EEGE)(6)(PO)(2)/L64 1:1 and 1:10], or rearrange by dissociation of the large composite particles [(PO)(2)(EEGE)(6)(PO)(2)/P85]. The presence of a Pluronic micellar peak in the relaxation time distribution at lower temperatures, the dimensions of the composite particles, and the different behavior of the systems at elevated temperatures are discussed. A possible application of the thermosensitive mixtures in delivery/release of active substances is suggested.     

Effect of tetraalkylammonium salts on the tacticity of poly(methyl methacrylate), 2.. Initiation by potassium tert-butoxide

The anionic polymerization of methyl methacrylate was carried out in the presence of potassium tert-butoxide (t-BuOK)/quaternary ammonium salts (QAS) in toluene and tetrahydrofuran at −60°C. It was found that in toluene some QAS additives substantially increase the syndiotacticity of poly(methyl methacrylate). Two types of QAS were distinguished, quite different in their action. The addition of QAS with one or two longchain alkyl groups (>C₁₂), does not change significantly the mode of the monomer addition, whereas the polymerization in the presence of tetraalkylammonium salts with four equal substituents and dimethyldidodecylammonium bromide yields predominantly a syndiotactic polymer with high conversion and comparatively low polydispersity (M̄_w/M̄_w = 1.3−1.5). In some cases QAS additives are more effective modifiers than cryptand [2.2.2].