Electron impact fragmentation of isomeric 2‐diazo‐2‐cyanoacetamides and 4‐cyano‐5‐hydroxy‐l,2,3‐triazoles

On the basis of electron impact mass spectra, high-resolution mass spectra and metastable ion spectra, the isomerization of the molecular ions of N-aryl-2diazo-2cyanoacetamides and l-aryl-4-cyano-5-hydroxy-1,2,3-triazoles into each otber or into the common structure has been demonstrated. Corresponding N-cyclohexyl derivatives are unable to undergo such a transformation. It is known that 2-diazo-2-cyanoacetamides undergo cyclization in the presence of bases with formation of 4-cyano-5-hydroxy-l,2,3-triazoles.' This study was initiated in order to elucidate whether such a transformation proceeds in the gas phase under electron impact (EI). Analysis of the mass spectra of unsubstituted 2diazo-2-cyanoacetamides demonstrated absence of isomerization of M +' of these compounds into isomeric 1,2,3-triazoles. * However, a simple comparison of the spectra of N-aryl-2-diazo-2-cyanoacetamides (1-3) and isomeric l-aryl-4-cyano-5-hydroxy-1,2,3-triazoles (5-7) shows