Über die Acylierung von 4.5‐Diamino‐1.2.4‐triazolen

Gehlen, Heinz; Röbisch, Gerhard

doi:10.1002/jlac.19626600116

Cited by 14 publications

(10 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…According to the literature,8 triazolo[3,2‐ c ]triazoles can be prepared by the reaction of 3,4‐diamino‐1,2,4‐triazoles with acyl chlorides or acetic anhydride (R′ = CH 3 ) in pyridine at reflux. By using a large excess of the acylating agent, the fused system was obtained with the secondary amide at N5 from which, by basic hydrolysis, the final compound was obtained (the 5 H tautomer).…”

Section: Resultsmentioning

confidence: 99%

“…By using a large excess of the acylating agent, the fused system was obtained with the secondary amide at N5 from which, by basic hydrolysis, the final compound was obtained (the 5 H tautomer). However, it must be acknowledged that the only analytical data reported in ref 8. are elementary analyses, which, of course, do not provide real proof of either the regiochemistry of amide formation or which tautomer is formed upon hydrolysis of the secondary amide.…”

Section: Resultsmentioning

confidence: 99%

“…A comprehensive experimental and theoretical analysis of this fused heterocycle is missing. One detailed account of the synthetic procedures was given in the 1960s but without any comment on its tautomerism (only the 5 H isomer was assumed) 8. Subsequently, tautomerism of the system was formally acknowledged,9 but only the 3 H and 5 H tautomers were considered.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Tautomerism in the Fused N‐Rich Triazolotriazole Heterocyclic System

et al. 2013

View full text Add to dashboard Cite

Tautomerism in the [1,2,4]triazolo[3,2‐c][1,2,4]triazole fused aromatic system has been investigated by single‐crystal X‐ray analysis, UV/Vis spectroscopy and theoretical calculations on selected new heterobicycle derivatives. The reactions of 3,4‐diamino‐1,2,4‐triazoles with acyl chlorides or acetic anhydride in pyridine at reflux led to ring closure and the fused aromatic system was obtained as the secondary amide at N2 instead of at N5 as previously reported in the literature. For the [1,2,4]triazolo[3,2‐c][1,2,4]triazole system, three different tautomers can be present. Crystal structure analysis showed the presence of only one tautomer or, depending on the packing, a mixture of two; theoretical calculations supported this finding, predicting that for all the investigated compounds one tautomer is energetically disfavoured with respect to the other two. The electronic absorption spectra of some compounds show a marked solvent dependence, which has been interpreted, with the help of theoretical calculations, in terms of acid/base equilibria, which are critically dependent upon the substituents at the heterobicycle.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Tautomerism in the Fused N‐Rich Triazolotriazole Heterocyclic System

et al. 2013

View full text Add to dashboard Cite

show abstract

“…the effect on alkaline phosphatase enzyme was RESULTS AND DISCUSSION Chemistry-The reactions outlined in Schemes I and I1 were followed amino-5-aryl-1,3,4-oxadiazoles (v) were prepared by first condensing the chosen aldehydes (11) with semicarbazide hydrochloride (111) in the reported association Of activities with for the synthesis of the desired compounds. The key intermediates, 2-also The susceptibility of the 1,3,4-o&iazole moiety to attack with potassium hydroxide (2) and mines (18) may be important to the predicted bioactivity ofthe presence of sodium acetate followed by oxidatiGe ring closure of the resulting aldehyde semicarbazones (IV) with aqueous iodine-potassium iodide in presence of sodium carbonate (19). A previous report (20) showed that the exclusion of sodium carbonate in the cyclization of IVo prepared compounds.…”

mentioning

confidence: 99%

“…Found: C,64.3;H,5.8;N,13.8. ~-Amino-5-aryl-l,3,4-oxadiazoles (V)-These were prepared from IV by a reported method (19). Anal.-Calc.…”

mentioning

confidence: 99%