Unexpected formation of benzaldehydes by the reactions of dithioacetals derived from cinnamaldehydes with 2,3-dichloro-5,6-dicyano-p-benzoquinone in aqueous solvents

1,3-Dithianes 1 , 1,3-dithiolanes 2 , and diphenyl dithioacetals 3 derived from cinnamaldehydes reacted with 2,3-dichloro-5,6-dicyano-p-benzoquinone in aqueous solvents to give benzaldehydes 4 . Hydride transfer from 1–3 to 2,3-dichloro-5,6-dicyano-p-benzoquinone followed by hydrolysis and oxidative carbon-carbon bond cleavage would produce benzaldehydes 4 .     

The crystal structure and absolute configuration of the antitumor platinum complex trans(OH)-Pt(OH)2(malonato)(1R,2R-cyclohexanediamine).

The absolute configuration of the anti-tumor complex trans(OH)-Pt(OH)2(malonato)(1R,2R-cyclohexanediamine) was determined by X-ray anomalous scattering technique. The final unit cell was monoclinic, space group P2(1) with a = 9.142 A, b = 7.788 A, c = 11.946 A, beta = 96.48 degrees, Z = 2. The crystal structure was determined by direct method and difference Fourier synthesis, and refined to R = 0.025 and Rw = 0.033 based on 2768 independent reflections. The platinum atom has roughly octahedral coordination. The cyclohexane ring has the expected chair configuration, with two amino groups in equatorial positions while the malonato ligand, in contrast, shows a boat conformation for six membered Pt O-C-C-C-O ring.     

On the selection of the optimal plasticizer for calix[n]arene-based ion-selective electrodes: Possible correlation between the ion selectivity and the ‘softness’ of the plasticizer

A criterion for the selection of a suitable plasticizer for calix[n]arene-based ion-selective electrodes is discussed. The cation selectivity of plasticized membranes without the ligand was first measured as a reference. The membranes can be roughly classified into two groups. The first group shows cation selectivity in the order Cs⁺+>K⁺>Na⁺>Li⁺. The membranes in the second group are made of phosphorus plasticizers, which show a selectivity in the reverse order. The plasticizers in the first group featured a linear relationship between the dipole moment of the plasticizer (calculated by a PM3 method) and the ratio of cesium selectivity to lithium selectivity. The linear relationship supports the view that the polar membrane which includes a soft plasticizer with a large dipole moment shows selectivity for Cs⁺, whereas the nonpolar membrane including the soft plasticizer with the small dipole moment shows much lower selectivity for Cs⁺. Next, 2-fluorphenyl-2-nitrophenyl ether (FPNPE) which showed the highest Cs⁺ selectivity and tris(2-ethylhexyl)phosphate (TEHP) which showed the highest Li⁺ selectivity were mixed in an appropriate ratio to make membranes with a different affinity for hard ions. The metal selectivities of several crown-based and calixarene-based ionophores were examined in these membranes. Although a few exceptions exist, the polar soft membrane is favorable when the interfering metal ion is hard, whereas the hard membrane is favorable when the interfering metal ion is soft.     

Studies on steroids. CCLIII. Capillary gas chromatographic behaviour of diethylhydrogensilyl-diethylsilylene derivatives of stereoisomeric bile acids.

The capillary gas chromatographic behaviour of diethylhydrogensilyl (DEHS) ethers and/or diethylsilylene (DES) derivatives of fifty bile acids including 4- and 6-hydroxylated compounds is described. The methylene unit (MU) values of methyl and pentafluorobenzyl esters of bile acids were determined as their trimethylsilyl (TMS), dimethylethylsilyl (DMES) ethers and DEHS-DES derivatives. The differences in methylene unit values between the corresponding TMS ethers and DMES ethers or DEHS-DES derivatives were used for estimating the number and stereochemistry of hydroxyl groups on the steroid nucleus. On treatment with the silylating agent N,O-bis (diethylhydrogensilyl)trifluoroacetamide, bile acids possessing isolated hydroxyl in addition to diaxial trans-glycol groups were easily converted into the DEHS ehters, whereas those having a vicinal glycol group except for the diaxial group were converted into cyclic DES derivatives. The mass spectrometric properties obtained with negative-ion chemical ionization detection are discussed.     

Studies on intramolecular nh-bridging in aromatic compounds. Part 3 [1–3]

A study was made of the use of calcium oxide as a catalyst at a temperature of 400–700° for the dehy-drocyclization of four primary arylamines: 2-aminobiphenyl, 1-aminotriphenylene (5c) , 2-phenoxyaniline, and N-(2-aminophenyl)pyrrole. Maximal yields of cyclized products isolated were 53% (carbazole), 52% (4H-naphtho[1,4-def]carbazole), 18% (phenoxazine), and 0%, respectively. Comparison is made with reported cyclizations of the corresponding nitro and azido starting materials. In one case, treatment of I-nitrotriphenylene with triethyl phosphite produced mainly diethyl N-(1-triphenylenyl)phosphoramidate (51%). Mono- and hemihydrochlorides of 5c are described. A mechanism for the catalyzed dehydrocy-clization is proposed.     

High-sensitive elemental analysis using multi-parameter coincidence spectrometer: GEMINI-II

In this study, using neutron activation analysis with multi-parameter coincidence method which was developed at Japan Atomic Energy Agency (JAEA), a non-destructive, ultra-high sensitive multi-elemental determination has been realized. The multi-parameter coincidence method is carried out with an array of 19 germanium detectors, GEMINI-II. Using this system, very weak γ-rays emitted from trace amounts of elements can be detected. The iridium concentration has been determined by means of neutron activation analysis with multi-parameter coincidence method for Cuban sediment samples across the K/T boundary strata.     

Ab initio molecular orbital study of the reactivity of active alkyl groups. V. Nitrosation mechanism of acetone with syn-form of methyl nitrite

The mechanisms of nitrosation of acetone through sodium enolate [CH3CO1CH2]-Na+ (1) or naked enolate [CH3CO1CH2]- (2) with methyl nitrite CH3O3NO2 (3), and the reactivity of the syn-form of 3 (syn-3) during the C-N bond formation process were investigated using ab initio molecular orbital (MO) methods. Our results have demonstrated the predominant formation of E-1-hydroxyimino-2-oxo-propane CH3COCH=NOH (4E) when the complex [CH3CO1CH2NO2(O3CH3)]-Na+ was produced kinetically via a metal-chelated pericyclic transition state (TS(CHELATED)), in which the O3 atom of syn-3 was coordinated to the Na+ atom of 1.     

The crystallographic structure of the natural air-hydrate in Greenland dye-3 deep ice core

We have carried out X-ray diffraction studies on single crystals of natural air-hydrate in deep ice cores recovered at Dye-3 Greenland. Integrated intensities for 470 diffracting planes were measured by an automated four-circle diffractometer. The space group determined is cubicFd3m and the lattice constant is 17.21(3) Å. These results indicate that the crystallographic structure is the Stackelberg's structure II, in contrast to the previously anticipated structure. This finding agrees with the recent results on the synthetic air-hydrate by Davidsonet al. It was also found by difference Fourier synthesis for guest molecules that electron density in a 16-hedral cage has multiple maxima displaced from the center of the cage while that in the 12-hedron was approximately spherical.Dedicated to Dr D. W. Davidson in honor of his great contributions to the sciences of inclusion phenomena.     

Grassmann manifold of aJH-algebra

We study the set of rankp idempotents in a topologically simple Hilbert Jordan algebra (JH-algebra for short). To produce the differential geometric structure on, we establish Jordan algebraic results concerning the structure of some two-generator subalgebras. We identify geodesics, the Riemannian distance and the sectional curvature of by using the Jordan algebraic structure.