Synthesis of Pyrano, Pyrido, Oxazino, and Spiro Pyrazole Derivatives and Their Antimicrobial Activity
- PDF / 235,844 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 66 Downloads / 263 Views
ynthesis of Pyrano, Pyrido, Oxazino, and Spiro Pyrazole Derivatives and Their Antimicrobial Activity E. F. Abdelrahmana,*, W. Shehtaa, M. G. M. Assya, and M. E. Farhana a
Department of Chemistry, Faculty of Science, Zagazig University, Zagazig, 44519 Egypt *e-mail: [email protected] Received December 20, 2019; revised July 24, 2020; accepted July 31, 2020
Abstract—Condensation of 5-methyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one with 4-hydroxybenzaldhyde in alcoholic sodium hydroxide yielded 4-(4-hydroxybenzylidene)-5-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3one, and treatment of the latter with acetylacetone, hydrazine hydrate, ethyl cyanoacetate, and ethyl acetoacetate gave pyranopyrazole, pyrazolopyrazole, and pyrazolopyridine derivatives. 5-Methyl-2-phenyl-1,2-dihydro-3Hpyrazol-3-one was reacted with 2,4-dichlorobenzoyl isothiocyanate, thiosemicarbazide, and hydrazine hydrate to afford pyrazolooxazine, pyrazolopyrazole, and spiro[pyrazole-3,3′-pyrazolo[3,4-c]pyrazole] derivatives. Some of the newly synthesized compounds showed high antimicrobial activity against three microbial strains (S. aureus, E. coli, C. albicans). Keywords: pyranopyrazole, pyrazolopyrazole, pyrazolopyridine, pyrazolooxazine, antimicrobial activity
DOI: 10.1134/S1070428020100267 INTRODUCTION In recent years, much attention has been focused on the synthesis of nitrogen heterocycles because of their biological and medicinal importance. Pyrazolones and their derivatives constitute a significant class of heterocyclic compounds which can be found in many natural and synthetic products and medicinally active molecules [1, 2]. They are interesting because of their substantial pharmacological and biological activities such as antioxidant, antiplatelet, anti-inflammatory, antitumor, enzyme inhibitory, analgesic, antifungal, and antibacterial [3–10]. Therefore, the synthesis of functionalized pyrazolone structures is a hot topic in synthetic chemistry, and a great deal of work has been reported on this subject [11–14]. Increasing antibiotic resistance in microbial populations requires search for alternate cellular targets for new antimicrobial agents. It is well known that small modifications in the structure of targets change their biological character and physiochemical properties. A survey of literature on antimicrobial activity of various types of compounds revealed that the presence of certain pharmacophore such as pyrazole in any molecule plays an important role in improving the activity [15–17].
Herein we report the synthesis and antimicrobial activity of some new fused pyrazole derivatives such as pyranopyrazole, pyrazolopyrazole, pyrazolopyridine, and pyrazolooxazine. RESULTS AND DISCUSSION 5-Methyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one (3) was synthesized by the condensation of ethyl acetoacetate (1) with phenylhydrazine (2). The reaction of 3 with 4-hydroxybenzaldehyde in acetic acid in the presence of sodium acetate afforded pyrazolone 4 due to the activation of the 5-CH3 group via protonation of the endocyclic nitrogen atom, whereas pyr
Data Loading...
