Die Suche nach den sogenannten Estern der Knallsäure

Abstract

The preparation of the so-called esters of fulminic acid (R—ONC) – a yet unknown class of compounds – has been an intriguing problem to chemists for nearly a century. This review article draws an integral picture of the various approaches which have been attempted to prepare and isolate a substance of this nature. The methods investigated originate in isonitrile chemistry; they include alkylation of inorganic fulminates, dichlorocarbene reaction (Hofmann's “carbylamine reaction”) with O-alkylhydroxylamines, dehydrohalogenation of O-alkyl-formohydroximoyl halides (also dehydration of alkyl formo- hydroxamates), nucleophilic attack on O-alkyl-2-oxoalkanecarbohydroximoyl chlorides, and finally flash pyrolyses of 4-alkoximino- and 4-aryloximino-5(4H)-isoxazolones.