Design, Synthesis, and Antifungal Activities of Novel 1,2,4‐Triazole Schiff Base Derivatives

Abstract

With the aim to find new compounds with high antifungal activity, 21 4-amino-5-substituted-1,2,4-triazole Schiff bases (2a - 2g, 3a - 3g, and 4a - 4g) were designed and synthesized. Their antifungal activities against Pythium solani, Gibberlla nicotiancola, Fusarium oxysporium f. sp. niveum, Gibberlla saubinetii, Alternaria iycopersici, Phytophthora capsici, Physalospora piricola, Cercospora arachidicola hori, and Fusarium oxysporium f. sp. cucumber were tested, parts of the compounds exhibited excellent antifungal activity. This research provides useful information for further study of antifungal agents.

Synthesis and antifungal activity of novel 1,2,4‐triazole derivatives containing an amide moiety

“…To a three‐necked round‐bottomed flask with a magnetic stirrer, the key intermediate 5 (0.02 mol) and 1‐substitutedpiperazine (0.02 mol) dissolved in dichloromethane (10 mL), 1H‐benzo[d] triazol‐4‐ol (0.02 mol), and 1‐(3‐dimethylaminopropyl)‐3‐ethylcarbodiimide hydrochloride (0.03 mol) were added. The reactions were reacted for 8 to 10 hours at room temperature.…”

“…All structures of aimed compounds were confirmed by 1 H NMR, 13 C NMR, mass spectrometry (MS), and elemental analysis data. In the 1 H NMR spectra of 6a-6o, one singlet at δ 3.71-3.74 and 3.82-3.85 were attributed to nine protons of the Ph-OCH 3 . A singlet at δ 4.24 ppm integrating for two protons was assigned to CH 2 protons of SCH 2 CO .…”

“…As an extension of this approach, the structure-activity relationships (SAR) were deduced on the basis of the antifungal activity values in Table 1. Table 1 showed that with the presence of the alkyl group in the R substituent group, smaller alkyl substituent groups could increase the antifungal activities against B. dothidea and B. cinerea in the order of 6a > 6b > 6c, nevertheless, when R was CH 3 , the corresponding compound 6b demonstrated better antifungal activity against Phomopsis sp than the other target compounds. Meanwhile, when R was substituted phenyl, the electron-donating group ( OH) at 4-positions of phenyl could increase the antifungal activities against B. dothidea, Phomopsis sp, and B. cinerea in the order of 6 g > 6 h > 6i.…”

“…Some 1,2,4‐triazole compounds had been developed as commercial pesticide molecules, such as difenoconazole, prothioconazole, exoxiconazole, and amicarbazone (Figure ). Recently, differently substituted 1,2,4‐triazoles have been reported for their wide biological activities, such as antibacterial, antifungal, antiviral, insecticidal, and herbicidal activity.…”

“…for their wide biological activities, such as antibacterial, [1,2] antifungal, [3][4][5] antiviral, [6] insecticidal, [7] and herbicidal [8,9] activity.…”