Synthetic studies on β-lactam antibiotics. 15. conversion of 7-epicephems into 1-oxacephems

7-Epi-1-oxacephem was obtained by stereospecific, intramolecular etherification of alcohol prepared from 7-epicephems via aldehyde or formate. Synthesis of the 3-acetoxymethyl analogwas unsuccessful. Biologically active 1-oxacephems were derived from by known processes.     

Synthesis in the diazasteroid group VI. A synthesis of 2,3-dimethoxy-15-methyl-8,15-diazaestra-1,3,5(10)triene

Homoveratrylamine (II) was condensed with 3-(2-carbomethoxyethyl)-1,3-dimethyl-2-pyrrol-idone (Ib) to furnish the corresponding amide (III), which was subjected to the Bischler-Napieralski reaction to afford the corresponding dihydroisoquinoline derivative (IV). Compound V was obtained by the reductive ring closure of Vila which was obtained by the hydrogena-tion of IV. The stereochemistry of V is proposed to have the anti-trans-trans quinolizidine conformation.     

Ab initio mo study on base stacking: Adenine-adenine interaction in single-stranded polyadenylic acid (Poly A)

The interaction energy for base stacking in single-stranded poly A is calculated by an ab initio MO method. The calculated value agrees well with the observed stacking enthalpy. Dispersion and charge transfer interactions are the main factors stabilizing the polynucleotide; the contribution of the former is dominant.     

The morphology of polyethylene prepared by γ-ray-induced polymerization in various solvents

Polyethylenes were prepared by γ-ray-induced polymerization in ethyl and n-butyl alcohols, tert-butyl alcohol containing 5 vol-% of water, 2,2,5-trimethylhexane, 2,2,4-trimethylpentane, and cyclohexane in the temperature range 25–90°C. The morphology of the polymers as-polymerized and studied by electron microscopy depends on three factors through the degree of undercooling: the affinity of the solvent, polymerization temperature, and the polymer molecular weight. Large lamellar crystals are formed even in the alcohols when at least two of them are chosen properly.     

Liquid-liquid equilibria for four ternary systems containing methanol and cyclohexane

Nagata, I., 1984. Liquid-liquid equilibria for four ternary systems containing methanol and cyclohexane. Fluid Phase Equilibria, 18: 83–92.Liquid-liquid equilibria have been obtained experimentally for the systems methanol-benzene-cyclohexane, methanol-toluene-cyclohexane, methanol-acetone-cyclohexane and methanol-2-propanol-cyclohexane at 298.15 K. The experimental results are compared with predicted values obtained from the UNIQUAC and extended UNIQUAC equations.