Synthesis of Novel Indole Schiff Base Compounds and Their Antifungal Activities

Abstract

A series of novel indole Schiff base derivatives (2a–2t) containing a 1,3,4-thiadiazole scaffold modified with a thioether group were synthesized, and their structures were confirmed using Fourier transformed-infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR), carbon nuclear magnetic resonance spectroscopy (13C NMR), and high resolution-mass spectroscopy (HR-MS). In addition, the antifungal activity of synthesized indole derivatives was investigated against Fusarium graminearum (F. graminearum), Fusarium oxysporum (F. oxysporum), Fusarium moniliforme (F. moniliforme), Curvularia lunata (C. lunata), and Phytophthora parasitica var. nicotiana (P. p. var. nicotianae) using the mycelium growth rate method. Among the synthesized indole derivatives, compound 2j showed the highest inhibition rates of 100%, 95.7%, 89%, and 76.5% at a concentration of 500 μg/mL against F. graminearum, F. oxysporum, F. moniliforme, and P. p. var. nicotianae, respectively. Similarly, compounds 2j and 2q exhibited higher inhibition rates of 81.9% and 83.7% at a concentration of 500 μg/mL against C. lunata. In addition, compound 2j has been recognized as a potential compound for further investigation in the field of fungicides.

Synthesis, Characterization, Antibacterial and Antioxidant Activities of Cu(II), Ni(II), and Zn(II) Mixed Ligand Complexes Containing Isoniazid Based Bidentate Schiff Base

“…"Nevertheless, they are utilized in organic synthesis, medicine, chemical catalysis, pharmaceutics, chemical analysis, and new technologies" [7]. These complexes exhibit a wide range of activities, including antibacterial [8][9][10], antifungal [11][12], anticancer [13][14], and anti-inflammatory agents [15][16]. "Schiff base metal complexes are efficient catalysts in both homogeneous and heterogeneous processes" [17][18][19], and "the function of these metal complexes varies depending on the ligands, coordination sites, and metal ions" [20].…”