Aromatic Systems with 10π Electrons Derived from 3a-Azapentalene. Part 40. Studies on the 1,2,4-Triazolo[4,3-b][1,2,4]triazole Series

Abstract

The synthesis, structure, and reactivity of several 1,2,4-triazolo[4,3-b][1,2,4]triazole derivatives have been studied. Structures have been established throughout a careful carbon-13 NMR study, and for the most unusual one (inner salt of 2-methyl-3-methylthio-6-phenyl-7H-1,2,4-triazolo[4,3-b][1,2,4]triazolium hydroxide) by X-ray crystallography: the space group is P21/c, the cell constants are a=12.6939(5), b=16.0936(6), c=12.0239(5) and β=107.247(3)° and Z=8. The S-methyl group is directed towards the fusion of the five-membered rings at +/−syn conformations. The azapentalene moieties have the first atoms of the substituents on its plane and the 6-phenyl rings make an angle of −26.7 and −4.3° with it, in the two independent molecules respectively.

Synthesis and properties of N-aminoazolinethiones and N-aminoazinethiones 2. Reactions

“…CLXXIX followed by the pyrazolotriazoles CLXXX were obtained analogously from 4-amino-l-methylthio-3-R-1,2,4-triazoles. The corresponding 1,2,4-triazolo[4,3-b]-l,2-4-triazoles were formed in excellent yields when derivatives of 4-amino-3-methylthio-l,2,4-triazole CLXXXVI or CLXXXVII reacted with aromatic nitriles [148,149]. Interaction of the pyrimidinium salts CLXXXIX with primary amines or hydrazines was accompanied by the Dimroth rearrangement [152].…”