Near‐IR Absorbing Nickel(II) Porphyrinoids Prepared by Regioselective Insertion of Silylenes into Antiaromatic Nickel(II) Norcorrole

The treatment of an antiaromatic norcorrole Ni^II complex with a kinetically stabilized silylene provided ring‐expansion products in excellent yields through the highly regio‐ and stereoselective insertion into the β‐β pyrrolic C? C bonds. The resultant Ni^II porphyrinoid monoinsertion product exhibited relatively strong near‐IR absorption bands due to the small HOMO–LUMO gap in spite of the disrupted cyclic π‐conjugation by the silicon atom.     

Cyclic Acetal-Photosensitized Polymerization. VI. Photopolymerization of 2-Vinyl-1,3-dioxolane

The photopolymerization of 2-vinyl-l,3-dioxolane (VDO) was carried out in benzene at 40° C without use of the usual radical initiator. VDO was decomposed by means of photoirradiation to a cyclic acetal radical which transformed instantly into the ester radical by β-scission of dioxolane ring: the vinyl polymerization could be initiated by the ester radical. Because of the degradative chain transfer by allylidene group, the rate of polymerization and the molecular weight of polymer were very small.     

Physical and microbial collection efficiencies of an electrostatic precipitator for abating airborne particulates in postharvest agricultural processing

We constructed a single-stage, laboratory-scale electrostatic precipitator (ESP) and evaluated its physical and microbial collection efficacies. Ground rice husk was examined as a representative model of airborne particles carrying microorganisms (bacteria, molds and yeasts). Physical and microbial collection efficacies were evaluated at different voltages applied to the negative discharge electrode without ozone generation. The best collection efficiencies were observed at an applied voltage of ?6.0 kV, resulting in collection efficiencies of over 90% for the physical sample and 99.95% for bacteria. No molds or yeasts in the ground rice husk passed through the ESP operating at ?6.0 kV applied voltage.     

High‐Yielding Synthesis of the Anti‐Influenza Neuramidase Inhibitor (−)‐Oseltamivir by Three “One‐Pot” Operations

Taking shortcuts : A remarkably short and high‐yielding asymmetric total synthesis of (?)‐oseltamivir takes advantage of organocatalysis and single‐pot domino operations. The target, known as the drug Tamiflu, is prepared efficiently in a short time, and also its derivatives can be synthesized effectively.

     

Nanocopying of individual DNA strands and formation of the corresponding surface pattern of titania nanotube

Titania nanotube was prepared by nanocopying of the individual DNA double strand as template. DNA was first spread on a solid substrate, and its molecular surface was coated with an ultrathin titania layer by 3 cycles of the surface sol-gel process. Fluorescence microscopic images before and after titania coating of the DNA/YOYO-1 complex were essentially identical, showing that the titania coating did not change the chemical properties of the complex. Titania coating effectively prohibited chemical degradation of titania-coated DNA with DNase I and physically separated the DNA strand from the surrounding environment with an ultrathin titania barrier. The morphology of the DNA strand was preserved, as confirmed by microscopic and spectroscopic observations. The presence of the hollow (tubular) structure was confirmed by a silver staining experiment coupled with scanning transmission electron microscopy-energy-dispersive X-ray spectroscopy (STEM-EDX) analysis. The present finding shows the effectiveness of nanocopying of the individual DNA strand.     

Rare-earth silylamide-catalyzed selective dimerization of terminal alkynes and subsequent hydrophosphination in one pot

[reaction: see text] Rare-earth silylamides, Ln[N(SiMe3)2]3 (Ln = Y, La, Sm), catalyzed regio- and stereoselective dimerization of terminal alkynes in the presence of amine additives to give conjugated enynes in high yields. The additives played a crucial role to depress the oligomerization and to control the regio- and stereochemistry of the dimerization. Thus, the selectivity for (Z)-head-to-head enynes was increased in the order of tertiary < secondary < primary amine additives. On the other hand, the reversed order was observed for the formation of head-to-tail dimers. When alpha,omega-diynes were subjected to the dimerization, very novel cyclic bisenyne compounds were given through double-dimerization in satisfactory yields. In addition, an application of the system allowed subsequent hydrophosphination of the enynes generated in situ with diphenylphosphine, giving rise to 1-phosphinyl-1,3-dienes as the sole products in excellent yields after oxidative workup.     

Total synthesis of (-)-ascochlorin via a cyclobutenone-based benzannulation strategy

The application of a convergent benzannulation strategy in an efficient synthesis of (-)-ascochlorin is described.