Pyridines, 1-oxides—continued sodium

In the production of 4,4 -bipyridyl from pyridine, the reaction between pyridine and metallic. sodium in liquid ammonia is involved, followed by oxidation. By adopting a continuous reactor, the process has been made safer and yields have probably improved. For a hazardous chemical like diazomethane, even at a capacity of 60 tpa a continous plant has been adopted. 

The spectroscopic probe pyridine-N-oxide was used to characterize polar microdomains in reverse micelles in supercritical ethane from 50 to 300 bar. For both anionic and nonionic surfactants, the polarities of these microdomains were adjusted continuously over a wide range using modest pressure changes. The solubilization of water in the micelles increases significantly with the addition of the cosolvent octane or the co-surfactant octanol. Quantitative solubilities are reported for the first time for hydrophiles in reverse micelles in supercritical fluids. The amino acid tryptophan has been solubilized in ethane at the 0.1 wt.% level with the use of an anionic surfactant, sodium di-2-ethylhexyl sulfosuccinate (AOT). The existence of polar microdomains in aggregates in supercritical fluids at relatively low pressures, along with the adjustability of these domains with pressure, presents new possibilities for separation and reaction processes involving hydrophilic substances. 

New ways continue to be reported of carrying out familiar transformations of pyridine A -oxides. Thus a number of pyridine A -oxides have been deoxy-genated in acetonitrile with trimethylsilyl chloride-sodium iodide and zinc. The method is not so high-yielding when electron-withdrawing substituents are present. " The complexes that are formed by pyridine A -oxides and antimony pentachloride lose hydrogen chloride on heating subsequent hydrolysis yields 2(l//)-pyridones (Scheme 23). ... 

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