Direct conversion of allylic alcohols into N-acyl-α-amino acids by catalytic amidocarbonylation by means of homogeneous binary systems

N-Acyl-α-amino acids are synthesized by the amidocarbonylation of allylic alcohols catalyzed by homogeneous binary systems which consist of cobalt carbonyl and rhodium (or iron or palladium) complexes.     

Reaction of sulphoximides with diazomalonate in the presence of Cu-salt : A new synthesis and stereochemistry of optically active oxosulphonium ylides

Sulphoximides (Ia–Ie) were found to react with dimethyl diazomalonate (DDM) in the presence of a catalytic amount of Cu-salts affording the corresponding oxosulphonium ylides in moderate yields. The reaction did not proceed at all under irradiation of UV light. (?)-Methylphenyloxosulphonium bis(methoxycarbonyl)-methylide ((?)-IIb) was obtained from (+)-(S)-methylphenylsulphoximide ((+)-(S)-Ib) together with (?)-(S)-methyl phenyl sulphoxide ((?)-(S)-IIIb) by this reaction. Hydrolysis of (?)-IIb gave (+)-methylphenyloxosulphonium methoxycarbonylmethylide ((+)-IIf) which was converted to (?)-(S)-IIIb upon treatment with dibenzoylethylene. Stereochemical cycle starting from (+)-(S)-Ib to (?)-(S)-IIIb was established and the absolute configurations of both ylides, (?)-IIb and (+)-IIf were assigned as (R)-configuration. The stereochemical courses, namely from (+)-(S)-Ib or (?)-(S)-IIIb to (?)-(R)-IIb or (+)-(R)-IIf to (?)-(S)-IIIb were determined as retention processes. The optical purities of the oxosulphonium ylides obtained from both reactions, (+)-(S)-Ib→(?)-(R)-IIb and (?)-(S)-IIIb→(?)-(R)-IIb, were almost equal. These results indicate that the mechanism of the reaction of sulphoximides with carbenes (or carbenoids) involves the initial formation of the sulphoxides which react subsequently with carbenes to afford the final products.     

A novel method for preparation of 2-(methyl- or phehnylthio)alkanoic esters

Ethyl 2-acetylalkanoate gave ethyl 2-(methyl- or phenylthio)alkanoate in high yield on treatment wiht CH₃SSO₂CH₃, PhSSO₂Ph, or PhSSPh in the presence of small excess of EtONa in EtOH. Application of the present method to synthesis of pellitorine and the queen substance is also described.     

Raman spectra of stilbene negative ions in tetrahydrofuran solution

Raman spectra of stilbene mono- and di-negative ions in tetrahydrofuran solution were obtained by Ar⁺ laser exciting lines. A considerable frequency shift was observed for several vibrations in the successive steps: stilbene → (stilbene)^? → (stilbene)^2?. The observed shift is discussed in a simple VB scheme, particularly in comparison with the results on anthracene negative ions. The resonance Raman effect was striking for both ions with intensity maxima at the exciting wavelengths close to the absorption maxima.     

Preparation of aromatic copolyesteramides by the direct polycondensation with a vilsmeier adduct derived from tosyl chloride and N,N-dimethylformamide

The reaction promoted by Vilsmeier adduct derived from tosyl chloride (TsCl) with N,N-dimethylformamide (DMF) was successfully applied to the preparation of copolyesteramides of high molecular weights directly from aromatic dicarboxylic acids, diamines, and bisphenols. The polycondensation was significantly affected by the reaction of activated dicarboxylic acids with bisphenols and diamines. Addition of a mixture of bisphenols and diamines likely caused gelation of the reaction mixtures, resulting in insoluble polymers, especially with high mol % diamines. Stepweise addition of them, however, gave the homogeneous reaction mixtures and copolymers of better solubility. These phenomena were studied in terms of sequence length distribution of polyester units, which was estimated by thermal analyses of the random copolymers prepared under various conditions for the initial reaction with bisphenols.     

Synthesis of enantiopure 1,2-diamine attached to cross-linked polystyrene and its application to an insoluble catalyst for asymmetric hydrogenation

A novel enantiopure 1,2-diamine (5) having two phenolic hydroxy groups was attached into chloromethylated polystyrene through benzyl ether linkage, which was used as a chiral ligand of the catalyst in asymmetric hydrogenation of acetophenone.     

Highly sensitive automatic analysis of polycyclic aromatic hydrocarbons in indoor and outdoor air

A method for the quantitation of polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor air by high-performance liquid chromatography (HPLC) with a spectrofluorometric detection and programmed excitation and emission wavelength pairs is proposed. The mobile phase is a linear gradient of methanol-water. The relative standard deviations (n = 5) are in the range 0.38-1.7% at concentration levels of 0.69-11.40 ng ml(-1). The determination limits (S N = 10 ) are 0.5-15.9 pg. The proposed method was successfully applied to quantitate 12 PAHs in gas phase and particulates in indoor and outdoor air. The recoveries of PAHs from gas phase and particulates were 95.7-117.5 and 94.8-112.4%, respectively. This highly sensitive automatic HPLC analysis for PAHs both in gas phase and particulates can be applied to indoor and outdoor survey.     

Heat capacity and dual spin-transitions in the crossover system [Fe(2-pic)3]Cl2·EtOH

The heat capacity of [Fe(2-pic)₃]Cl₂·C₂H₅OH Crystal (2-pic: 2-picolylamine) has been measured with an adiabatic calorimeter between 13 and 315 K. Two phase transitions centered at 114.04 and 122.21 K were observed. This finding accords with recent prediction of possible existence of two-step spin-conversion (H. Köppen et al., Chem. Phys. Lett., 91 (1982) 348). The total transition enthalpy and entropy amounted to ΔH = 6.14 kJ mol^?1 and ΔS = 50.59 J K^?1 mol^?1. The transition entropy consists of the magnetic contribution (13.38 J K^?1 mol^?1), the orientational order-disorder phenomenon of the solvate ethanol molecule (8.97) and the change in the phonon system, in particular the change in stretching and deformation vibrations of the metal-ligand (28.24).     

Metallic Na formation in/on NaCl crystals with irradiation by electron or vacuum ultraviolet photons

Metallic Na was formed in/on NaCl single crystals by irradiating them with a variety of radiation sources, namely, 21 MeV electron pulses, an electron beam of 30 keV and photon fluxes in the VUV region. The physical states were analysed using several methods, optical absorption, lifetime measurement of positron annihilation, Auger electron spectroscopy and UV photoelectron spectroscopy. Metallic Na was obtained in different physical states; clusters were formed in bulk, thin layers (islands) and thick layers on the surface.