Synthesis of mono and bis-substituted asymmetrical compounds, (1-(pyridin-2-yl)ethylidene)carbonohydrazide and 1-(2'-hydroxybenzylidene)-5-(1'-pyridylethylidene)carbonohydrazone: Structural characterization and antioxidant activity study

Abstract

Carbonohydrazide was used for synthetizing a new dissymmetrical bis-substituted Schiff base 1-(2'-hydroxybenzylidene)-5-(1'-pyridylethylidene)carbonohydrazone (2). A mono substituted compound (1-(pyridin-2-yl)ethylidene)carbonohydrazide (1) was firstly prepared by condensation reaction of carbonohydrazide and 2-acetylpyridine in 1:1 ratio. Secondly, compound 2 was obtained by condensation reaction of compound 1 and salicylaldehyde in 1:1 ratio. The prepared compounds were characterized by elemental analysis, infrared and 1H and 13C NMR spectroscopy techniques, and the structure of compound 2 was determined by single-crystal X-ray diffraction study. The compound 2 (C15H15N5O2) crystallises in the monoclinic space group P21/c with the following unit cell parameters: a = 8.3683(3) Å, b = 13.9986(4) Å, c = 12.1610(4) Å, β = 97.512(3)°, V = 1412.37(8) Å3, Z = 4, T = 100(2) K, μ(MoKα) = 0.098 mm-1, Dcalc = 1.398 g/cm3, 6057 reflections measured (5.708° ≤ 2Θ ≤ 54.962°), 6057 unique (Rsigma = 0.0395) which were used in all calculations. The final R1 was 0.0474 (I > 2σ(I)) and wR2 was 0.1971 (all data). The oxygen atom O1 and the azomethine nitrogen atom N5 adopt cis-configuration relative to the C8-N4 bond, while O1 adopts trans-configuration with the azomethine nitrogen atom N2 relative to C8-N3 bond. The crystal packing of compound 2 is stabilized by intramolecular O(phenol)–H···N(carbohydrazide) and intermolecular N (carbohydrazide)–H···O (carbo-hydrazide) hydrogen bonds which form layers parallel to [010] axis. Additional C–H···O hydrogen bond consolidate the structure. The carbonohydrazide moiety C=N–N–C(O)–N–N=C fragment and the phenyl ring are almost coplanar; with an angle of 1.73(1)° between their means plans. The dihedral angle between the mean planes of the phenyl and the pyridine rings is 22.267(2)°.

Synthesis, crystal structure, and spectroscopic characterization of a new non-centrosymmetric compound, 1-(2-chloroquinolin-3-yl)-N-(4-fluorobenzyl)methanimine

“…Furthermore, the values of C15-F1 and C10-Cl1 are 1.364(3) and 1.749(3) Å, respectively (Table 2). These values are consistent with those reported in the literature [17][18][19][20]. Intramolecular interactions determine the supramolecular structure of the title compound (Table 3).…”

“…The melting points were measured with a Koffler hotstaged apparatus and were not corrected. 1 H, 13 C and 19 F NMR spectra were recorded with CDCl3 as the solvent on a Bruker-300 spectrometer. Chemical shifts δ are reported in ppm relative to TMS as an internal reference.…”

“…13 C NMR (75 MHz, CDCl3, δ, ppm): 160.8 (HC=N), 121.1-161.5 (Ar-C), 64.5 (CH2-N). 19 F NMR (282 MHz, CDCl3, δ, ppm): -115.35.…”

“…2-Chloroquinolin-3-yl)-N-(4-fluorobenzyl)methanimine (3) was successfully synthesized in three steps and the compound obtained was characterized by 1 H,13 C and19 F NMR techniques. In addition, the obtained molecular structure by the single crystal X-ray diffraction study of the title compound confirms the suggested molecular structure.…”

Synthesis, Crystal Structure and Spectroscopic Study of (E)-2-methoxy-4-((1-phenylethylimino)methyl)phenol

“…The band characteristic of the presence of aromatic ring are pointed in the range 1577-1450 cm -1 [27]. In addition, the characteristic bands of deformation vibrations of out-of-plane aromatic C-H bonds are pointed at 865 cm -1 and 769 cm -1 .…”