Synthesis and characterization of triazolotriazines

  • Elizabeth J. Gray

Student thesis: Doctoral ThesisDoctor of Philosophy

Abstract

The Dimroth rearrangement in ring-fused 1,2,4-triazoles has been reviewed in detail in Part I and the synthesis of all known triazolo-triazines is described in Part II.
Experimental investigations concerned the establishinent of the skeletal arrangement of a variety of triazolotriazines formed by several synthetic routes.
Interaction of 3-amino-5-hydrazino-12,4-triazole and benzilafforded 2-amino-6, 7-diphenyl-1, 2,4-triazolo[ 5, 1-c-]-1,2,4-triazine,whereas cyclization of 5,6-diphenyl-3-hydrazino-1,2,4-triazine withcyanogen bromide resulted in the isomeric 3-amino-6,7-diphenyl,-1,2,4-triazolo [4, 3-b]-1,2,4-triazine: both amines were deaminated with amyl nitrite in boiling tetrahydrofuran without rearrangement of the heterocyclic skeleton. 6,7-Diphenyl-1,2,4-triazolo[5,1-cJ-1,2.4-triazine, synthesized from 3-hydrazino-1,2,4-triazole and benzil, formed a covalent hydrate which could be detected spectroscopically in solution, and a
covalemt methanolate and ethanolate which could be isolated.
A new route to 3-amino-5-hydrazino-pyrazole is described and cyclization to 7-amino-3,4-diphenyl-pyrazolo[ 5,1-.c]-1,2,4-triazine was achieved with benzil.
The diazonium nitrate of 3-amino-1,2,4-triazole coupled with ethyl cyanoacetate to yield a mixture of two geometrical isomers of ethyl 2-(2H-1,2,4-triazol-3-ylhydrazono) cyanoacetate.Recrystallization of the crude coupling mixture from aqueous ethanol gave a single hydra-zone which cyclized predominantly to ethyl 7-amino-1,2,4-triazolo[5,1-c]-1,2,4-triazine-6-carboxylate in acid conditions and 6-cyano-1,2,4-triazolo[ 5,1-c]-1,2,4~triazin-7(4H)-one under basic conditions. The nature of the cyclizing medium also controlled the cyclization of .the (pyrazol-ylhydrazono) cyanoacetate hut the corresponding (tetrazol-
ylhydrazono) cyanoacetate gave only ethyl 7-aminotetrazolo[ 5,1-cJ-1,2,4-
-triazine-6-carboxylate. 2-( 2H-1,2,4-Triazol-3-:ylhydrazono) malonitrile
cyclized unambiguously to 7-amino-6-cyano-1,2,4-triazolo-[ 5,1-c]-1,2,4-
triazine.
Drastic hydrolysis of ethyl 2-(2H-1,2,4-triazol-3-yllhydrazono)-cyanoacetate,
ethyl 7-amino-1, 2,4-triazolo[ 5,1-c]-1,2,4-triazine-6-carboxylate,
6-cyano-1,2,4-triazolo[ 5,1-c]-1,2,4-triazin-7{ 4H)-one and 7-amino-6-
cyano-1,2,4-triazolo[5,1-c]-1,2,4-triazine gave a hydrate of 1,2,4-triazo1o[5,1-c ]-1,2,4-triazin-7(4H)-one.
Mass spectral fragmentations of 7-aminoazolo-[5,1-c]-1,2,4-triazinesconfirm that the azole ring is more stable than the 1,2,4-triazine ring on electron impact.

Date of AwardJul 1976
LanguageEnglish
SupervisorMalcolm F.G. Stevens (Supervisor)

Keywords

  • Synthesis
  • characterization
  • triazolotriazines

Cite this

Synthesis and characterization of triazolotriazines
Gray, E. J. (Author). Jul 1976

Student thesis: Doctoral ThesisDoctor of Philosophy