Furoxans thermolysis, nitrile oxide generation

Stable furoxans are convenient starting compounds for generating short-lived nitrile oxides XCNO (X = ONC, NC, Cl, Br, and Me) by thermolysis (10, 11, 80, 81). The thermolysis of benzotrifuroxan (200°, in excess PhCN) proceeds (Scheme 1.6) with the cleavage of the C-C and 0-N(0) bonds in only one furoxan ring to give bifuroxan bis(nitrile oxide). The latter undergoes further reactions such as cycloaddition with PhCN or conversion to bisisocyanate (82). 

---