Synthesis and Characterization of Pyrazole Heterocyclic Derivatives via Vilsmeier-Haack-Reaction and its Schiff`s Bases.

Abstract

The synthesis of New Schiff bases (2; and 3a-c) is reported in this study. These bases were created by reacting -chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde (1) with various amines that contained various pharmacophore atoms or groups, such as derivatives of benzothiazole and aniline, in the hopes of having antimicrobial and antifungal properties. Using mild reaction conditions and a good yield percentage, mono-pyrazole Schiff bases (2 and 3a–c) were designed and synthesized by reacting 5-chloro--3-methyl-1-phenyl-pyrazole-4-carbaldehyde (1) with substituted aniline. These compounds were then combined with Vilsmeier reagent to create amino acrolein products (4a–c), which interacted with hydrazine, piperidine, and hydroxylamine hydrochloride when boiling ethanol, producing the expected heterocyclic systems at position 3 of the pyrazole ring in good and moderate yields. Spectral data was used to corroborate the chemical structure of the newly synthesized Schiff bases linked pyrazole core.