Cyclopropane formation from 4,5-unsaturated thiophenylethers: Conversion of limonene into car-2-ene

Strong bases can abstract a proton α to double bond. A phenylthio group ψ to that double bond can be eliminated at the same time leading to a cyclopropane ring. The procedure is illustrated by a conversion of limonene into car-2-ene.     

Development of chiral stabilised azomethine ylids: A chiral memory relay system.

Chiral, stabilised azomethine ylids incorporated in cyclic templates derived from (R)- or (S)-2-phenylglycinol and (S)-valine undergo enantioselective 1,3-dipolar cycloaddition reactions with a variety of dipolarophiles. Removal of the template in the case of adducts derived originally from (S)-valine furnishes enantiomerically pure -substituted proline derivatives.     

Search for disoriented chiral condensate in 158<Emphasis Type="Italic">A</Emphasis> GeV Pb+Pb collisions in WA98 experiment

The current status of the search for localized domains of disoriented chiral condensates (DCC) in Pb+Pb collisions at 158A GeV/c are presented. A new method based on the discrete wavelet transformation (DWT) technique along with an analysis of correlation between charged and neutral particles has been used for the search of localized DCC domains. We show that both the methods indicate the presence of non-statistical fluctuations in data.     

A laser extraction/combustion technique for in situ delta(13)C analysis of organic and inorganic materials

A CO(2) laser extraction system is described for in situ delta(13)C analysis of organic and inorganic materials. Carbonaceous compounds volatilized by the laser are quantitatively converted to CO(2) gas by a combustion furnace mounted after the sample chamber. Gases produced by the laser and combustion processes are swept by helium carrier gas and separated by a packed gas chromatography column prior to their introduction to an isotope ratio monitoring mass spectrometer. A sample of lentil bean was analyzed at a spatial resolution of 200 μm and yielded delta(13)C values with precision of +/- 0.3 per thousand. The accuracy of delta(13)C measurements was better than +/- 0.5 per thousand from NBS 22 (mineral oil), USGS 24 (graphite), and IAEA CO-1 (calcium carbonate). Copyright 1999 John Wiley & Sons, Ltd.     

Investigation of statistical,block and graft copolymerizations using nmr-sensitive initiators and macroinitiators

¹³C- and ³¹P-NMR studies on polymers and copolymers derived from ¹³C-enriched AIBN, ¹³C-enriched dibenzyl ketone and diphenyl-2,4,6-trimethylbenzoylphosphine oxide (Lucrin TPO) are reported. They provide information about the influence of solvent on the initiation step in copolymerization reactions, the selectivity of diphenylphosphinyl radicals and the chemical behavior of radicals derived from dibenzyl ketone. In addition, NMR, molecular weight and molecular weight distribution measurements on polymers obtained from polymerizations of methyl methacrylate conducted in the presence of stilbene indicate that stilbene or radicals derived from it may be able to moderate MMA polymerizations.