1.2.4- Triazolidine-3,5-dione 1,2-ylids

Pyrolysis of pyridine derivatives is a method for allylic and benzylic deamination the preparation of nitriles from aldehydes, and the preparation of isocyanates from acid chlorides or hydrazides Flash vacuum pyrolysis continues to yield interesting reactions and products. Recently, it has been reported that quite sensitive acetylene derivatives can be obtained by this method from 4-alkylideneisoxazol-5(4H)-ones by ring degradation. On the other hand, 2 carbamyl azide molecules cyclize under these conditions to form l,2,4-triazolidine-3,5-dione 1,2-ylids . 2H-Cyclohepta[b]furan-2-ones have been obtained by ring expansion of phenyl propiolates... 

Without additional reagents l,2,4-Triazolidine-3,5-diones from l,2,4-triazolidine-3,5-dione 1,2-ylids... 

Dry l,l-Diethyl-4-diethylamino-l,2,4-triazolidine-3,5-dione 1,2-ylid pyrolyzed l-ethyl-4-diethylaminourazole. Y 91%. F. e. s. W. Lwowski et al., Tetrah. Let. 1971 y 425 l,2,4-triazolidine-3,5-diones cf. G. Zinner and U. Gebhardt, Arch. Pharm. 304y 706 (1971). 

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