On Triazoles. VI. The acylation of 5‐amino‐1,2,4‐triazoles

Abstract

The isomeric and tautomeric structure of I and II type monoacylated 5‐amino‐1,2,4‐triazole derivatives was studied with the help of their ir, uv, pmr and cmr spectra as well as model compounds prepared for this purpose. It was stated that the structure of the I type ring‐acylated derivatives is 2o and those of their II type isomers is 5a.

Acyl and Sulfonyl Derivatives of 3,5-Diamino-1-R-1,2,4-triazoles

“…The band for the free amino group vibrations at 3370-3470 cm -1 disappears from the IR spectra ( Table 2). The UV spectra were analogous to the spectra of the two acylamino-1,2,4-triazoles described in [11]. The structure of compound 13b was confirmed by its hydrogenation to the dialkyl derivative 14.…”

“…The UV spectra of the acyl derivatives having no additional chromophores in the acyl group, are analogous to the spectra of acylamino-1,2,4-triazoles described in the literature [11].…”

“…The values of the absorption frequencies of the carbonyl group of compounds 3a-f,i,j (1650-1680 cm -1 ) indicate that the acyl group is linked with one of the amino groups and not with the nitrogen of the triazole ring [2,3,11]. Otherwise the frequency of the vibrations of the carbonyl group must have a higher value (1700-1735 cm -1 ) [3,11].…”

Alkylation of acyl and sulfonyl derivatives of 3,5-diamino-1-phenyl-1,2,4-triazole

“…Such an alkylation route is typical of the majority of amino azoles and azines in which the amino group is conjugated with the pyridine type nitrogen atom of the heterocycle [7]. Thus alkylamino-1,2,4-triazoles are usually prepared by cyclization of alkyl substituted acyclic precursors [3, 8-10], hydrogenation of arylideneamino-or acylamino-1,2,4-triazoles [11][12][13], or ammonolysis of halo-substituted 1,2,4-triazoles [4].We have proposed that the alkylation reaction route for the amino-1,2,4-triazoles can be altered by initial acylation or sulfonation of the amino group. In the presence of base an electron acceptor acyl (sulfonyl) group can facilitate deprotonation and give a conjugated N-anion, alkylation of which can give the N-acyl(sulfonyl)-N-alkylamino-1,2,4-triazoles.…”

“…Such an alkylation route is typical of the majority of amino azoles and azines in which the amino group is conjugated with the pyridine type nitrogen atom of the heterocycle [7]. Thus alkylamino-1,2,4-triazoles are usually prepared by cyclization of alkyl substituted acyclic precursors [3, 8-10], hydrogenation of arylideneamino-or acylamino-1,2,4-triazoles [11][12][13], or ammonolysis of halo-substituted 1,2,4-triazoles [4].…”