Flash vacuum pyrolysis, and

Acetonitrile oxide was generated from 3,4-dimethylfuroxan oxide by flash vacuum pyrolysis and trapped at -40 °C where its and NMR spectra were examined. Warming to room temperature in the presence of propane produced 3,5-dimethyl-2-isoxazoline (Scheme 108) (79TL2443). The oxide could also be generated by photolysis of furoxan (68CC977). 

Online coupling of flash-vacuum pyrolysis and mass spectrometry was applied to 3,4-dicyano-l,2,5-oxadiazole-2-oxide (dicyanofuroxan). The 1,2,5-oxadiazole is almost quantitatively pyrolyzed at 500-600 °C. Using collisional activation, the main pyrolysis products were identified as NCCNO and (CN)2 <1997BSB545>. 

Gas-phase analytical methods, flash vacuum pyrolysis and, 21 139-140 Gas-phase decomposition, of Group III organometallics, 22 156 Gas-phase grown carbon fibers, 26 736-737 Gas-phase height of a transfer unit (HG), 1 51-52... 

Hetastarch, 4 112 Heter-ionic interactions, 8 77 Heteroatom-containing functional groups, flash vacuum pyrolysis and,... 

Hydroxypyrazoles and the corresponding pyra-zolinone tautomers were investigated by Perez, El-guero, and co-workers by flash vacuum pyrolysis and... 

Phosphorus is present in zinc dialkyldithiophosphate and deactivate platinum catalysts in engine exhaust systems. Using zinc, antimony and oxothiomolybdate dialkyl-dithiocarbamate (MoDTC) complexes alone or in combination with other lubricating oil additives appears to solve this problem. Antimony complexes are used also as extreme pressure agents while molybdenum ones as friction modifier additives (Hill et al., 1994). Analyses of Zn(dtc)2 decomposition using the thermogravimetric method, flash vacuum pyrolysis, and four-ball machine... 

The flash vacuum pyrolysis and the mass spectrometric fragmentation of a series of five methyl substituted phenanthrenes were correlated with each other in a quaUtatively predictable way.i ) The major thermochemical products for these compounds generally corresponded to one of the five most intense fragment ions in the compound s electron impact mass spectrum. The importance of products which corresponded to ions with high appearance potentials increased with increasing temperature in the thermolysis system. 

Scheme 1. General apparatus for flash vacuum pyrolysis and/or flow pyrolysis [10]...

Scheme 5. Syntheses of the circulenes 16 and 17 from suitable sulfones by flash vacuum pyrolysis and aromatization [49,50]...

There is still little, if any, substantive data on the structure-reactivity profile of different heterocyclic -quinodimethanes, but the expected trends are supported by experience. The stability of the -quinodimethanes appears to be related to the loss of aromatic character o-quinodimethanes derived from the more stable aromatic heterocycles are the most reactive. Thus, when generated by flash vacuum pyrolysis and condensed at low temperatures, some heterocyclic rt-quinodimethanes can be isolated. It is clear that the furan derived. species 7 is considerably more stable than the thiophene analogue 2. The species 7 is sufficiently. stable for NMR spectra to be recorded at -60 °C and Diels-Alder adducts can be obtained by adding dienes to the cold finger <81JA669I>. In contrast, the species 2 can be observed directly only in an argon matrix <88CB791> and it readily polymerises even in the presence of dienophiles. Similar qualitative trends are observed with other heterocyclic o-quinodimethanes. 

High yields of the mixture of products that is illustrated here are obtained, and many examples are given to demonstrate the synthetic utility and to show how the formation of the reduced non-cyclized products can be avoided. The potential of the imine function in heterocyclic synthesis is widely appreciated, and the thermal generation of imines has been known for some time. A new report of their formation by flash vacuum pyrolysis and subsequent intramolecular trapping constitutes a novel retro-ene-Diels-Alder sequence, e.g. (140) -> (141). Although the yields are not good, improvements will no doubt be developed. 

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