Selectivity of amidrazones towards activated nitriles – synthesis of new pyrazoles and NMR investigation

Abstract

N-Arylbenzamidrazones reacted with 2-(ethoxymethylene)malononitriles in ethanol/DMF (20:1), catalyzed by triethylamine (Et3N), to give 65-81% yields of the corresponding pyrazoles. The structures of the products were proved by IR, mass, and NMR spectra and elemental analyses. Two-dimensional NMR correlations were used to differentiate between possible structures. The reaction mechanism is also discussed.

Microwave Assisted Synthesis, Characterization and Biological Study of New Chalcones

“…The frequency was adopted to 400 MHz for 1 H NMR and to 100 MHz for 13 C NMR. The 1 H NMR spectra of the chalcone compounds were indicated presence four types of protons; aromatic ring protons which showed signals between 6.42 ppm and 8.53 ppm, (C=CH) protons that neighbor the protons of aromatic ring appear signal between 7.45 ppm and 8.5 ppm, protons of methoxy groups which showed singlet signal at the chemical shift between 3.5 ppm and 3.89 ppm, and protons of methylene group (-CH2-) exhibited triplet signal ranged from 4.10 ppm to 4.48 ppm [37][38][39]. However, additional signals were found in X2 and X5, (6.00-6.11 ppm) and 2.5 ppm, belonged to protons of methylene group and two-protons of primary amino group, respectively [38][39][40][41].…”