Reactions of diphenylcyclopropenone with ketenes in the presence of nickel tetracarbonyl

Reactions of diphenylcyclopropenone with ketenes in the presence of catalytic amounts of nickel tetracarbonyl have been studied. In these reactions, 1 : 1 cycloadducts, cyclopentene-1,2-dione derivatives, were obtained in yields above 80%. The cycloaddition reactions were significantly affected by solvents, and DMF was the most suitable solvent. Iron pentacarbonyl did not act as a catalyst. Reaction mechanisms are discussed.     

Mikrotaktizit?t und mittlere Sequenzl?ngen von stereospezifischen Polymeren, die durch Kontrolle durch symmetrische und asymmetrische Stellen erhalten wurden

Ohne Zusammenfassung     

Realization of a Gravity-Capillary Wave Surface Using Sub-Nyquist Spectral Samples

A method for numerical realization of a full gravity-capillary wave surface that is specified by a wave-spectral model and a dispersive relationship of the surface wave is developed on the basis of the angular spectral representation of a random water surface. A significant aspect of the method is that it requires a smaller number of spectral samples than that required by the Whitteker-Shannon sampling theorem for the complete generation of a full gravity-capillary wave surface, without resulting in any appreciable errors in auto-correlation functions for the surface displacement or surface slopes. The method enables the unified treatment of gravity and capillary waves in numerical studies of higher order characteristics of the thermal radiation emitted from, and the light scattered by, the wave surface.     

Real-time Optical Wavelet-Transform with Positive and Negative Signals

An opto-electronic hybrid system that is based on the joint transform correlator (JTC) is suggested for the implementation of real-time wavelet transform. Holographic encoding of both the object signal and wavelet function enables the JTC-based real-time correlator to execute the optical wavelet transformation involving positive and negative values. We suggest an interferometric method to retain the information about the polarity of the final wavelet transform. The principle of this method is verified by experiments.Presented at 1996 International Topical Meeting on Optical Computing (OC ‘96), April 21-25, Sendai, Japan.     

Synthesis of (±)-methylenolactocin and (±)-trans cognac lactone

The title compounds were efficeintly synthesized from 3-fuancarboxylic acid via the Birch recuction-elimination.     

Enzymatic synthesis of flavin adenine dinucleotide

A new and simple enzymatic method for the synthesis of flavin adenine dinucleotide (FAD) from flavin mononucleotide by the transadenylylation reaction using microbial cells is described. Among various microorganisms tested,Artherobacter globiformis IFO 12138 and two soil bacteria were selected as useful enzyme sources. Under suitable reaction conditions, the amount of FAD synthesized was 2.25 μmol/mL with cells ofA. globiformis. The transadenylylation reaction could be coupled with the ATP supplying system through a glycolysis process with yeast.     

An asymmetric synthesis of α-tocopherol side chain

A stereospecific synthesis of (3R,7R)?3,7,11-trimethyldodecanal (2) with highly optical purity was achieved by utilizing the coupling reaction of the amino sulfone (9) with(R)?3,7-dimethyloctyl magnesium bromide (7), and the asymmetric isomerization of the resulting(E)-allylic amine (10).     

A package compound of a metal atom with a hydrocarbon [4][4][4][4][3](1,2,3,4,5)ferrocenophane

Perbridged ferrocenes ($\text{9}$ and $\text{11}$: the title compound) have been synthesized and characterized by spectroscopies and X-ray diffraction, and an interesting rotational disorder has been found by the X-ray crystal analyses of both $\text{9}$ and $\text{11}$.     

Giant meso-meso-linked porphyrin arrays of micrometer molecular length and their fabrication

On the basis of the Ag(I)-promoted coupling reaction of zinc(II)-5,15-bis(3,5-dioctyloxyphenyl)porphyrin Z1, chain elongation has been attempted by using a stepwise doubling approach, which provides Z2, Z4, Z8, Z16, Z32, Z64, Z128, Z256, Z384, and Z512. The porphyrin arrays up to Z128 are sufficiently soluble in CHCl3 and THF despite their very long molecular lengths and rodlike structures, while the arrays over Z128 show a significant drop in solubility and stability. The discrete porphyrin arrays thus isolated were characterized by means of (1)H NMR spectroscopy, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry, UV/Vis spectroscopy, gel-permeation chromatography (GPC), cyclic voltammetry (CV), single-crystal X-ray crystallography, scanning tunneling microscopy (STM), and atomic force microscopy (AFM). Contrary to expected linear conformations of the arrays Z n (where n is the number of porphyrins), the single molecular images of Z128, Z256, and Z512 revealed largely bent structures; this finding indicates the substantial conformational flexibility of Z n. We also exploited an effective synthetic route by means of which Z n can be fabricated with a thiol-protected aryl group to provide Z n S(2) through Z n Br(2), by bromination with N-bromosuccinimide and subsequent Pd-catalyzed Suzuki-Miyaura arylation. Finally, the reaction of Z256 provided Z512, Z768, and Z1024. Collectively, this work provides an important milestone in the preparation of sub-microscale discrete organic molecules and the fabrication of molecular-based materials, hence significantly contributing to device applications.