2-amino-3-phenacyloxazolium salts

Hetzheim" summarized her investigations of ring transformations of 2-amino-3-phenacyloxazolium salts with oxygen and nitrogen nucleophiles to prepare substituted imidazolinones, imidazoles, imidazo[l,2-a]imidazoles, and 1,4-di-hydro-imidazo[2, -b [, 2,4]triazines. 

Quaternary oxazolium salts are easily cleaved by alkali iV-methylbenzoxazolium iodide affords iV-methyl-2-formamidophenol (135). iV-Methyloxazolium fluorosulfonates react with ethanolic ammonia to give imidazoles with sodium hydrogen sulfide, thiazolium salts are formed. Hydrolysis or aminolysis of 2-amino-lV-phenacyloxazolium salts (136) is followed by cyclization to yield imidazolones (137) or imidazoimidazoles (138), respectively (Scheme 5). 

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See also in sourсe #XX -- [ ]

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