Synthesis, Characterization and Antifungal Study of Five New Derivatives of E-1-(2-Hydroxyphenyl)chalcone

Abstract

In an attempt to search for new and efficient antifungal agents, five chalcones namely (E)-3-(4′-diethylaminophenyl), (E)-3-(2′-ethoxyphenyl), (E)-3-(3′,4′-diethoxyphenyl), (E)-3-(2′,3′-dihydrobenzofuran-5-yl) and (E)-3-(3′,5′-bis[trifluoromethyl] phenyl)-1-(2-hydroxyphenyl) prop-2-en-1-one were synthesized from 2-hydroxyacetophenone with the corresponding substituted benzaldehydes. The synthesized chalcones were characterized by GC-MS, FTIR, 1 H NMR and 13 C NMR spectra analysis. The antifungal activities of these chalcone derivatives were evaluated against five candida species using the agar diffusion method. All the compounds showed varying degrees of activity against the fungi with the compounds containing the 4′-(diethylamino)phenyl and 2′-ethoxyphenyl moieties being the most potent in the series against the pathogens with MIC between 25 and 50 µg mL −1. Results clearly revealed the electronic effect of substituents on the Bring of the chalcone on its antimicrobial activity with the compound containing the 4′-(diethylamino) substituent which is a strong electron releasing substituent, showing the highest activity while the compound containing the 3′,5′-bis[trifluoromethyl] substituent, which is a strong electron withdrawing substituent, showing a lower potency against the tested candida species.

Synthesis, Characterization and Antibacterial Activities of New Fluorinated Chalcones

“…A mixture of the appropriate benzaldehyde derivatives (5 mmol) and 4-fluoro-2-hydroxyacetophenones (1) (5 mmol) in 98% ethanol (20 mL) was stirred in a round bottom flask and 50% NaOH solution (2 mL) was added gradually with constant stirring under reflux for about 5 h. The reaction mixture was allowed to cool to room temperature, then poured over crushed ice, acidified with 10% HCl until the reaction mixture was slightly acidic to wet litmus paper and allowed to stand overnight in an ice bath. The product formed was filtered using a vacuum pump, then washed several times with cold distilled water, dried and recrystallized from absolute ethanol [7,13].…”

“…The highest yield was obtained for compound (6) containing 2,3-dihydrobenzofuran moiety while compound (7) gave the least yield. The poor yield of the later might be due to the bulky nature of trifluoromethyl substituents at the meta positions of the ring B that may hinder proper condensation of the reactants [13]. In general, the rate of reaction decreased in the order of 2,3-dihydrobenzofuran > 2-ethoxyphenyl > 3,4-diethoxyphenyl > 4-(diethylamino)phenyl > 3,5-bis[trifluoromethyl]phenyl with regard to substituents on the B-ring.…”

“…The 13 C NMR spectra showed highly deshielded carbonyl carbon resonance ranging from 192.43 to 192.97 ppm while the hydroxylated carbon (C-2) signals appeared from 164.82 to 166.08 ppm. The shift between 117.30 and 123.89 ppm was assigned to α-C while between 140.17 and 147.40 ppm to β-C of the conjugated chromophores [13] ( Table 2). The delocalization of electrons among the three carbon atoms of the chromophore resulted in the β-carbon resonance being more deshielded than α-carbon.…”

Development of Antimicrobial, Antimalarial and Antitubercular Compounds Based on a Quinoline-Pyrazole Clubbed Scaffold Derived via Doebner Reaction

“…These molecules have been examined for decades and SAR (structure-activity relationship) analyses have been performed to determine their biological effects [9]. Derivatives containing quinoline ring has been reported as great antimicrobial [10,11], antimalarial [12,13] and anti-tubercular activities and also exist as structural sub-units of natural substances. Pyrazoles are popular illustrations of aromatic heterocycles incorporating two nitrogen atoms in their five-membered rings [14,15].…”

Synthesis, Antibacterial Activity and DFT Calculation of Naphtopyrano, Furo and Pyrazolo [3,2,e] [1,2,4]Triazolo-[1,5-c]Pyrimidine Derivatives

“…Pyranotriazolopyrimidine derivatives have attracted a great deal of interest due to their biological activities and their potential applications as pharmacological agents. Several derivatives of the pyranotriazolopyrimidine exhibit platelet anti-aggregating activity and local "inhibition of influenza, virus sialidase and mutagenic activity [1], anti-genotoxic activity [2], antimicrobial activity [3], AChE or acetylhydrolase inhibition [4], and antifungal [5,6]". Moreover pyranotriazolopyrimidine derivatives are well known antigenotoxic, [7] and in the agrochemical field, showing herbicidal activity [8].…”