Synthesis and Biological Evaluation of Novel Chalcone and Pyrazoline Derivatives Bearing Substituted Vanillin Nucleus

Abstract

A series of novel chalcone 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j, 4k, 4l and pyrazoline 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k, 5l derivatives have been synthesized as potential antibacterial agents. The pyrazoline derivatives 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 5i, 5j, 5k, 5l have been synthesized by reaction of various chalcones 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j, 4k, 4l with hydrazine hydrate in the presence of acetic acid. The chalcones 4a, 4b, 4c, 4d, 4e, 4f, 4g, 4h, 4i, 4j, 4k, 4l were prepared by the condensation of key aldehyde 3 with appropriate acetophenone using basic condition and ethanol as a solvent. The key aldehyde 3 has been synthesized by reacting 2‐(chloromethyl)‐3‐methyl‐4‐(2,2,2‐trifluoroethoxy)pyridine hydrochloride and vanillin. The structures of the new compounds were established on the basis of 1H‐NMR, mass, IR, and elemental analysis data. All the newly synthesized compounds were screened for their antibacterial activity against Escherichia coli, Salmonella typhi (Gram‐negative bacteria), Staphylococcus aureus, Micrococcus luteus (Gram‐positive bacteria) and antifungal activity against Candida albicans (fungi).

Synthesis and DFT Calculations of Novel Vanillin-Chalcones and Their 3-Aryl-5-(4-(2-(dimethylamino)-ethoxy)-3-methoxyphenyl)-4,5-dihydro-1H-pyrazole-1-carbaldehyde Derivatives as Antifungal Agents

“…Compound 4a showed the lowest MFC values against the three dermatophytes (31.25 µg/mL). In previous works Muškinja [ 10 ], Burmudžija [ 20 ], Patel [ 34 ] synthetized a series of chalcones and pyrazoline derivatives containing the vanillin moiety and tested them against several fungi including C. albicans and A. niger all of them showing negligible activity (MICs ≥ 625 µg/mL). Although the chalcone or pyrazoline derivatives reported by them differ from the series presented here in the substitution of the vanillin OH or in the ring A, the previous and presently reported compounds share the structural characteristics that they are both chalcones or pyrazolines and both possess the vanillin moiety as the B-ring, so our results add new important data to the activity of chalcone and pyrazoline vanillin derivatives possessing a vanillin moiety as ring B, corroborating that they are not good inhibitors of C. albicans , or Aspergillus spp., but adding an important finding that is their promising activity against dermatophytes and C. neoformans .…”

Quantitative Estimation of Few Novel Indole Derivatives using Spectroscopic Technique

“…There was also an absorption band at 1594, 1562, and 1590 cm -1 for the stated compounds 2, 3, and 4, which belonged to the C=C group. 13 The absorption bands at 1251, 1253, and 1251, on the other hand, belonged to the C-N group. 14 The chemical structures of the produced substances have been confirmed in all of these bands (2, 3 and 4) .…”

Therapeutic aspects of biologically potent vanillin derivatives: A critical review

“…The result indicated that the synthesized compounds were found to be exhibiting better antibacterial activity against the tested species. Thus, the replacement of phenyl ring with heterocyclic rings demonstrated significant antibacterial activity against commercial drugs 29 oxime with substituted benzoyl chlorides and found to be possessing considerable antimicrobial activity against bacterial and fungal species such as E. coli, S. aureus, P. aeruginosa, A. flavus, C. albicans and Chrysosporium keratinophilum. Hence, the presence of electron-withdrawing substituents such as fluoro and chloro group at the para position of aryl ester in both compounds has been found to be an essential part of the antimicrobial effect 31 .…”