Isoxazoles fulminic synthesis

The chemistry of nitrile oxides, in particular their application in organic synthesis, has been continuously developed over the past two decades and represents the main theme of this chapter. The parent compound, fulminic acid (formonitrile oxide), has been known for two centuries, and many derivatives of this dipole have been prepared since that time. Several simple and convenient methods for the preparation of nitrile oxides have evolved over the years. Dehydrochlorination of hydroximoyl chlorides was first introduced by Werner and Buss in 1894 (1). A convenient synthesis of isoxazoles was reported by Quilico et al. (2 ), and then the discovery of nitrile oxide cycloadditions to alkenes was subsequently noted by the same group (5). 

Flash thermolysis of 4-substituted isoxazol-5(4//)-ones can be used to generate alkynes, isocyanides, aminoisocyanides and ketenimines (77C258, 76HCA2615). Decomposition of the oxime (538) at an oven temperature of 450 °C produces C02, benzonitrile and fulminic acid (539 equation 5) (79AG(E)467). This method thus offers a safe alternative to the synthesis of fulminic acid from the explosive metal fulminates. 

By means of a synthesis of isoxazol derivs with fulminic acid, it was establish that the structure of the acid reported in Ref a is incorrect. It should be 3-isoxazole carboxylic acidl... 

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