N-tert-Butylbenzenesulfenamide-catalyzed oxidation of alcohols to the corresponding carbonyl compounds with N-chlorosuccinimide

N-tert-Butylbenzenesulfenamide (1)-catalyzed oxidation of various primary and secondary alcohols to the corresponding aldehydes and ketones was efficiently carried out by using N-chlorosuccinimide (NCS) in the coexistence of potassium carbonate and molecular sieves 4 Å at easy-to-control temperatures ranging from 0°C to room temperature. The present catalytic oxidation was performed without giving any damage to the functional groups in alcohols, and was particularly effective in the oxidation of alcohols that formed labile aldehydes because of its mild reaction conditions. Further, selective oxidation of primary hydroxy groups took place in 1-catalyzed oxidation of several diols. Mechanistic investigation suggested that the chlorination of the sulfenamide 1 by NCS led to the formation of a key species, N-tert-butylbenzenesulfinimidoyl chloride (2), which in turn oxidized alcohols in the presence of potassium carbonate to afford carbonyl products by accompanying regeneration of the catalyst 1.     

Time-Dependent Coupled-Channel Calculations of Muon-Transfer Cross Sections in Muonic Deuterium and Triton Collisions

A time-dependent coupled channel (TDCC) method has been developed to study rearrangement reactions in few-body Coulomb systems. We apply the TDCC method to muon transfer in muonic deuterium and triton collisions. The muon-transfer cross section (S-wave) is calculated for triton energies of 100 eV–3 keV. The present result is in good agreement with the previous calculation with the coupled rearrangement channel method [Hyp. Interact. 82 (1993), 45]. We also illustrate time evolution of wave functions to understand qualitatively the muon-transfer reaction.     

Gamow-teller strengths of the inverse beta transition 176Yb-->176Lu for spectroscopy of proton-proton and other sub-MeV solar neutrinos

Discrete Gamow-Teller (GT) transitions 176Yb-->176Lu at low excitation energies have been measured via the ( 3He,t) reaction at 450 MeV and at 0 degrees. For 176Yb, two low-lying states are observed, setting low thresholds Q(nu) = 301 and 445 keV for neutrino ( nu) capture. Capture rates estimated from the measured GT strengths, the simple two-state excitation structure, and the low Q(nu) in Yb-Lu indicate that Yb-based nu detectors are well suited for a direct measurement of the sub-MeV solar electron-neutrino ( nu(e)) spectrum including pp neutrinos.     

Development of a self-oscillating ultrasonic micro-motor and its application to a watch

We have developed an ultrasonic micro-motor for use as a micro-actuator in place of an electromagnetic motor. This ultrasonic micro-motor, which can be driven by a single signal and in which the change of the direction of the rotor movement can be made easily by selecting the electrode to apply the driving signal, can easily construct a self-oscillating circuit and simplify the driving circuit. We have also simplified the motor structure, which is easy to miniaturize and mass-produce. We applied a version of this motor with a diameter of 8 mm to a vibration alarm, and one with a diameter of 4.5 mm to a driving source of a calendar mechanism in a watch. This ultrasonic micro-motor is expected to be of use as a new driving source in a broad range of fields.     

Recent progress in biocatalysis for asymmetric oxidation and reduction

Latest advances for asymmetric synthesis through reduction and oxidation including deracemization by biocatalysts are reviewed. Newly developed methodologies as well as practical applications are covered.     

The first single-crystal X-ray structural refinement of the superconducting phase Li0.2(1) ZrNCl derived by intercalation

The single crystals of the superconducting Li_0.2(1)ZrNCl have been derived from the single crystals of β-ZrNCl by intercalation of lithium using an n-butyllithium solution in hexane. The crystal structure has been refined on the basis of the single-crystal X-ray data: the space group R-3m, a=3.591(1) Å, c=27.839(6) Å, Z=6, R1=0.0749 for 196 reflections and 12 variables. β-ZrNCl is isotypic with SmSI, while the structure of Li_0.2(1)ZrNCl can be described as the Li intercalated YOF type, a stacking variant of the SmSI type. The tightly bound slabs with a Cl-Zr-N-N-Zr-Cl sequence of close-packed layers are stacked rhombohedrally along the c-axis, with the van der Waals gaps between the chlorine layers hosting Li ions. This is the first single-crystal study on the Li intercalated phase. The structural changes from the pristine single crystals were precisely determined.