The structures of some 5-pyrazolones and derived 4-arylazo-5-pyrazolones

A new site‐selective route for synthesis of functionalized imidazo[2,1‐c][1,2,4]triazoles

“…Of these forms, structure A seems to be the form of choice as it is consistent with their electronic absorption and 1 H NMR spectra. For example, like typical hydrazones [23,24], the electronic absorption spectra of the products isolated in dioxane revealed in each case two characteristic absorption bands in the regions 410 -399 and 301 -287 nm ( Table 1). The spectra of the unsubstituted derivative 8a isolated from reaction of 1a with 3, taken as representative example of the series prepared, in different solvents exhibited little if any solvent dependence (Table 1).…”

Synthesis, azo-hydrazone tautomerism and antitumor screening of N-(3-ethoxycarbonyl-4,5,6,7-tetrahydro-benzo[b]thien-2-yl)-2-arylhydrazono-3-oxobutanamide derivatives

“…In agreement with this conclusion is the observation that the spectra of arylhydrazones derived from the reaction of quinones with N-alkyl-Nphenylhydrazine, unlike those of o-and p-hydroxyazo compounds, are largely independent of the solvent polarity. 12 This finding, while it excludes the azo tautomeric forms 4B and 4C, indicates that each of compounds 4 exists in one tautomeric form, namely 4A ( Figure 1). This conclusion was confirmed by the 1 H NMR and IR spectra of the studied compounds 4. characteristic for ester, acetyl and amide carbonyl groups, respectively.…”

In Situ Preparation, Structure, Photoluminescence and Theoretical Study of an Unusual Bismuth Complex

“…19 The peaks at 2360 cm -1 and 1690 cm -1 should be assigned to the stretching and bending vibrations of the C-N bonds. 20 The peaks at 1504, 1449 and 1277 cm -1 can be attributed to the stretching vibrations of the pyridyl rings of the N,N'-dimethyl-2,2'-bipy 2+ cations. 21 The peaks residing in the region of 888∼1173 cm -1 can be ascribed to the bending vibration of the pyridyl rings.…”