35Cl NQR frequencies were measured for N-chlorosuccinimide (NCS), N-chlorophthalimide (NCP), N,N′-dichlorobarbital (NDCB), sodium N,N′-dichloroisocyanurate dihydrate (Na-NDCI·2H2O) and N,N′,N″-trichloroisocyanuric acid (NTCI). The ionicities estimated by a 35Cl NQR study increased in the following order; NCS<NCP<NDCB<Na-NDCI·2H2O<NTCI. A linear relationship between the ionicities of chlorine atoms and the polarographic reduction potentials of N–Cl bonds was found. The ionicity was related to the reactivity.
The activity coefficients of aqueous solutions of dimethyl-β-cyclodextrin were measured by vapor pressure osmometry at 25, 35, and 45±0.1°C. The activity coefficient decreased with increase of concentration at each temperature. Both the excess enthalpy and the excess entropy were positive. The negative excess free energy originates from the large excess entropy term, indicating that dimethyl-β-cyclodextrin is a hydrophobic solute.
Regarding the Soret effect of prototropic ions of H+ and OH− in dilute aqueous solutions, it has been mentioned that heat-of-transport values for ions are in good agreement with those of the activation energies for ionic diffusion in the Arrhenius expression. The physicochemical significance of these facts is discussed in relation to the inclusion of thermal diffusion terms in Kramers’ formula for ordinary diffusion flux.
The structural change of Rh6(CO)16 supported on γ-Al2O3 surface during a decarbonylation–recarbonylation cycle was studied by means of EXAFS (extended X-ray absorption fine structure) spectroscopy. Rh6(CO)16 cluster framework was found to be decomposed into Rh(CO)2(OAl(Remark: Graphics omitted.))2 after the reaction with a mixture of O2 and H2O, and reversely regenerated by the subsequent treatment with a mixture of CO and H2O.
The X-ray crystal structure of a potentially five-coordinate palladium(II) complex containing 1,10-phenanthroline, [PdCl(PPh3)2(phen)][BF4]·(CH3)2CO has been determined. The structure was solved by the heavy-atom method and refined to R=0.051.
High-resolution 13C NMR spectra of the title complexes showed two type signals based on the “packing effect” and the long-chain alkyl group of the dioximato ligand was found to be fixed near the axial pyridine ligand in the solid state.
High-resolution 13C NMR spectra were measured for the CH3–C(=NOH)–C(=NOH)–R (R=CH3, C2H5, n-C3H7, and n-C4H9) series in the solid state. A commercially available powder, dimethylglyoxime (R=CH3), produced two C2 signals, indicating two isomers: i.e., s-trans-(E,E) and s-cis-(E,E). The ratio of trans: cis was estimated to be 3:1.
Zeylena, isolated from the roots of Uvaria zeylanica L. (Annonaceae), has been synthesized as a racemic modification by an intramolecular cyclo-addition reaction of DL-trans-2,3-dihydroxy-1-(benzoyloxymethyl)cyclohexa-4,6-diene 3-(E)-cinnamate or its acetate.
Copper(I) iodide-catalyzed cross-coupling reactions of (Z)-(1-trimethylsilyl-1-alkenyl)dicyclohexylboranes with allyl bromide or 1-bromo-1-hexyne gave stereoselectively (Z)-1,4-dienes or conjugated (Z)-enynes having a trimethylsilyl group on the internal carbon atom of the double bond.
The structures of amijitrienol and 14-deoxyisoamijiol, two new diterpenoids isolated from the brown seaweed Dictyota linearis, have been established as 1 and 2 on the basis of spectral and chemical evidence.
A process which can afford a large quantity of the title compound was explored by modifying the Horton’s original route. The developed process features highly stereoselective reduction of the oxime with sodium dihydrobis(2-methoxyethanolato)aluminate(1-) and efficient dehydrobromination with 1,8-diazabicyclo[5.4.0]undec-7-ene.
When treated with sodium hydrogentelluride in ethanol at room temperature, α-azido ketones are easily converted to pyrazines via the self-condensation of initially formed α-amino ketones followed by aerobic oxidation during work-up. On a similar treatment, activated α-azido bromide such as 1,2-diphenyl-1-azido-2-bromoethane suffers E2-type β-elimination to give the corresponding olefin as the sole product, while ordinary α-azido bromides afford complicated mixtures containing amino and olefinic compounds among other products.
Chiroptical properties of bis(2,4-dinitrophenyl) derivatives of acyclic diamino compounds were discussed. The derivatives of diamines in which the two NH2-bearing carbons are asymmetric having the same chirality exhibited Cotton effects of much larger intensity than the corresponding diamine derivatives having only one asymmetric carbon atom. Relation between sign and magnitude of Cotton effect at the longest wavelength of bis(2,4-dinitrophenyl) derivatives and structure and stereochemistry of parent diamino compounds was summarized in a tabulated form.
The crystal and molecular structure of the title complex has been determined by the use of the single-crystal X-ray diffraction method. The crystal of LaC40H58O8P3S8, F.W.=1155.20, is triclinic; space group P\bar1, a=13.300(5), b=19.816(8), c=11.257(4) Å, α=92.79(4), β=114.92(3), γ=75.40(4)°, U=2598(2) Å3, Z=2, Dm=1.48(3), Dx=1.48 g cm−3, and μ(Mo Kα)=1.29mm−1. Each lanthanum(III) atom is octa-coordinated and is in a dodecahedral geometry. The oxygen atoms of dibenzyl sulfoxide molecules are ligated at both ends of the base of a trapezia, and the chelating O,O′-diethyl dithiophosphates span two m edges and one a edge.
A single-term expression of the Nernst–Planck type equation conformable with nonequilibrium thermodynamics has been presented. The equation may be applicable to treat the electric properties of the multi-ionic system, although the individual ion flux is unobservable.
New bis(crown ether)s 3 consisting of a benzocrown unit and a monoazacrown unit connected by an oxyethylene linkage were synthesized. Their complexation behavior proved to be analogous to that of lariat monoazacrown ethers rather than that of bis(benzocrown ether)s.
Imidoyl chlorides were good substrates which can react with a variety of organotin compounds to give ketimines in the presence of a catalytic amount of palladium complex. Under similar conditions, C-tributylstannyl imines did not give the products except with 2-(tributylstannyl)benzothiazole, -benzoxazole, and 1-methyl 2-(tributylstannyl)imidazole. And N-tributylstannyl imines could not be utilized.
Cholesterol was oxidized (12% conversion) with platinum and oxygen to give several 7-oxygenated products, cholest-5-en-3-one, and cholest-4-en-3-one accompanied with its further oxygenation products at C-6. The pathways and mechanisms of the catalytic oxidation are discussed.