Modifications of the ozonolysis and Schiff staining of plasma lipoproteins reduce 11 pre-spectrometric steps to 3. Picrate denaturation of the lipoproteins and absorption spectrometry directly on the wet opaque membrane increase the sensitivity; the volume of sub-specimen needed per length of application site is reduced from 0.7 to 0.1 Atl/mm. Reasonably good proportionality between the total l...

A concise enantioselective synthesis of the advanced intermediate 5 for the synthesis of pumiliotoxins (Gallagher's intermediate) is described. The synthesis started from the regio- and trans-diastereoselective (dr = 98:2) reductive 3-butenylation of (R)-3-(tert-butyldimethylsilyloxy)glutarimide 14. After O-desilylation and Dess-Martin oxidation, the resulting keto-lactam 10 was subjected to a ...

Epoxidation of single-walled carbon nanotubes (SWNTs) may be carried out by the reaction of SWNTs with either trifluorodimethyldioxirane or 3-chloroperoxybenzoic acid; the resulting O-SWNTs are spectroscopically similar to those formed by ozonolysis. Quantification of the epoxide substituents is possible through the catalytic de-epoxidation reaction using MeReO3/PPh3 and the 31P NMR spectroscop...

The relative importance of competing pathways for the formation of high-molecular-weight peroxides in the ozonolysis of organic aerosol particles M. Mochida, Y. Katrib, J. T. Jayne, D. R. Worsnop, and S. T. Martin Division of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, USA Institute of Low Temperature Science, Hokkaido University, Sapporo, 060-0819, Japan Aerodyne...

The authors discuss three different mechanisms that could explain the observations. These include as yet unknown HOx recycling reactions, similar to that used to explain large daytime concentrations of HOx from the same campaigns; a source of HOx from nighttime ozonolysis reactions of highly reactive biogenic VOCs; and transport of radical reservoirs from a layer aloft to the surface. None of t...

1,3,5-Trioxane-2,4,6-trione (cyclic trimer of CO2) is the product of a four-step synthesis: chlorination of isobutyraldehyde; cyclotrimerization of 2-chloro-2-methylpropanal; dehydochlorination of 2,4,6-tris(2-chloropropan)-2-yl-1,3,5-trioxane; ozonolysis at -80 °C of 2,4,6-tri(propan-2-ylidene)-1,3,5-trioxane. This trioxane-trione is detected in solution at temperatures between -80 to -40 °C, ...

The planar structure of aculeximycin (1) produced by Streptosporangium albidum has been determined by spectral methods and chemical degradations such as 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU)-methanol reaction, ozonolysis, and periodative oxidation. The antibiotic consists of a 30-membered polyhydroxy lactone ring, an alpha, beta-unsaturated ester group, an intramolecular hemiketal, an oligos...