54986-26-4Relevant academic research and scientific papers
Thermolysis of 5-Alkylidene-1,4-dihydro-5H-tetrazoles
Quast, Helmut,Bieber, Lothar,Regnat, Dieter
, p. 1739 - 1747 (2007/10/02)
In benzene solution at 100 deg C, the isopropylidenedihydrotetrazole 1a decomposes mainly (80percent) into molecular nitrogen and the aziridinimines (E)- and (Z)-2a which are thermally unstable and afford methyl isocyanide and the imine 3a.In addition, the novel spirocyclic tetrahydropyrimidine 7a is formed (18percent yield) in a cycloaddition of 1a and the hypothetical intermediate 1,3-diazabutadiene 19a generated from 1a through a hydrogen shift and loss of molecular nitrogen.The thermolysis of the neopentylidenedihydrotetrazole 1b at 100 deg C is more complex.Only small amounts of the aziridinimines (E)- and (Z)-2b and their decomposition products 3b and methyl isocyanide are observed.A major product is the spirocyclic tetrahydropyrimidine 7b which exhibits moderate thermal stability.Slow thermolysis of 7b affords the tetrahydropyrimidinimine 8b and methyl azide.The latter reacts with 1b in a cycloaddition furnishing the spiro compound 5b which partially decomposes into the amino-1,2,3-triazole 16, thus regenerating methyl azide.This catalyzed isomerization 1b -> 16 which is initiated through the thermal cycloreversion of 7b involves a total of 19percent of 1b.The structures of the products are elucidated by means of mass spectra and high-field NMR spectra.The mechanism of formation of the 1,3-diazabutadienes 19 from 1 is discussed.
