Formation of non-racemic E- and Z-olefins based on discrimination of enantiotopic carbonyl groups in α-diketones by a chiral phosphonate reagent

A chiral HWE reagent reacted with an alternative carbonyl group of meso-α-diketones of bicyclo[2.2.1] system to give non-racemic (Z)- and (E)-olefins, respectively.     

Oxovanadium(V)-catalyzed enantioselective Meerwein-Ponndorf-Verley cyanation of aldehydes using acetone cyanohydrin

Oxovanadium(V)(salen) complex 4 was found to catalyze Meerwein-Ponndorf-Verley cyanation of aliphatic aldehydes with good to high enantioselectivity. This cyanation showed a positive nonlinear effect.     

Synthesis of a Stimuli‐Responsive P‐Chiral Polymer with Chiral Phosphorus Atoms and Azobenzene Moieties in the Main Chain

A reaction of the P‐chiral compound (S,S)‐1,2‐bis(boranato(tert‐butyl)methylphosphino)ethane with an azobenzene derivative gave stimuli‐responsive polymers with P‐chiral phosphines in the main chain. This is the first example of a stimuli‐responsive P‐chiral polymer. The polymer isomerized from the trans to the cis form upon UV irradiation and reverted to the trans form reversibly. The polymer was able to coordinate to platinum, and the resulting polymer complex exhibited the Cotton effect owing to the chirality of the phosphorus atoms. The structure of the P‐chiral polymer obtained could be changed reversibly by light and thermal stimuli, and the polymer chain was induced to rotate helically when complexed with transition metals through the chiral phosphorus atoms.     

Control of methanol oxidation by ionic behavior in supercritical water

In supercritical water the rate of methanol oxidation was controlled by ionic behavior as follows: the oxidation rate of methanol decreased with increasing proton and hydroxide ion concentration, possibly due to stabilization of the reactant, while that of CO was suppressed by added protons and enhanced by added hydroxide ions.     

Synthetic studies of vitamin D analogues. XI. Synthesis and differentiation-inducing activity of 1 alpha,25-dihydroxy-22-oxavitamin D3 analogues.

Six analogues of 1 alpha,25-dihydroxy-22-oxavitamin D3 (OCT) (2), 26,27-dimethyl OCT (5), 26,27-diethyl OCT (6), 24-norOCT (7), 24-homoOCT (8), 24-dihomoOCT (9), and 24-trihomoOCT (10) were synthesized from the 20(S)-alcohol (11) as the common starting material. In the activity inducing differentiation of human myeloid leukemia cells (HL-60) into macrophages, 26,27-dimethyl OCT (5) and 24-homoOCT (8) showed the highest activities. The binding properties of these analogues to the chick embryonic intestinal 1 alpha,25-dihydroxyvitamin D3 (1) receptor are also described.     

Quantification of 5-fluoro-2'-deoxyuridine in plasma by gas chromatography and negative-ion chemical ionization mass spectrometry.

A sensitive and specific method using gas chromatography and negative-ion chemical ionization mass spectrometry is described for the determination of 5-fluoro-2'-deoxyuridine (FdUrd) in plasma. The method is based on the formation of the pentafluoropropionyl derivative of FdUrd and of its stable isotope as internal standard after sample clean-up by solid-phase extraction and purification by high-performance liquid chromatography. Quantification in plasma was possible down to 300 pg/ml. The method was applied to the analysis of plasma levels of FdUrd in mice and dogs.     

Formation of pyrazine derivatives from D-glucosamine and their deoxyribonucleic acid (DNA) strand breakage activity

Two pyrazine derivatives [fructosazine (3) and deoxyfructosazine (6)] were simultaneously formed in a solution of D-glucosamine hydrochloride under various conditions. They showed deoxyribonucleic acid (DNA) strand breakage activity in plasmid pBR322 comparable to that of D-glucosamine. The DNA strand breakage by fructosazine (3) was stimulated by Cu2+.     

XPS study of one-dimensional compounds: TiS3

X-Ray photoelectron spectra of TiS₃ with a one-dimensional structure were measured. TiS₃ may be regarded as Ti⁴⁺(S₂)^2?S^2? with pairs of S atoms (S₂) and isolated S atoms. The spectra of the sulfur core-levels are assigned by comparison with those of TiS₂, where all S atoms are largely separated. The binding energy of the S₂ pairs is found to be 1.4 eV higher than that of the isolated S atoms, which is consistent with the larger negative charge of the isolated atoms. The structures of the valence band of TiS₃ are discussed in terms of a molecular orbital scheme for the S₂ pairs.