Sonochemical Synthesis of 2’-Hydroxy-Chalcone Derivatives with Potential Anti-Oomycete Activity

Abstract

This work reports on the synthesis of eight new 2′-hydroxy-chalcones with potential anti-phytopathogenic applications in agroindustry, among others, via Claisen–Schmidt condensation and ultrasound assisted reaction. Assays showed three chalcones with allyl moieties strongly inhibited growth of phytopathogenic oomycete Phytophthora infestans; moreover, compound 8a had a half maximal effective concentration (EC50) value (32.5 µg/mL) similar to that of metalaxyl (28.6 µg/mL). A software-aided quantitative structure–activity relationship (QSAR) analysis of the whole series suggests that the structural features of these new chalcones—namely, the fluoride, hydroxyl, and amine groups over the carbon 3′ of the chalcone skeleton—increase anti-oomycete activity.

Chalcones As Broad‐Spectrum Antimicrobial Agents: A Comprehensive Review And Analysis Of Their Antimicrobial Activities

“…The growth rate in world agricultural production and crops have slowed down due to this oomycetes diseases. [92] Phytopathogenic bacteria cause significant agricultural problems as they affect nutritional and commercially important crops. Fruits and plants are frequently attacked by such bacteria.…”

“…The Quantitative Structural Activity Analysis (QSAR) indicates that fluoride, hydroxyl and amino groups in the main chain of the chalcone increase anti-oomycete activity. [92] Xu et al, have demostrated that chalcone played a crucial role in prevention of antibacterial activity and on chalcones piperazine ring is very important for inhibiting the growth of bacteria (Figure 14) [97] Chen et al investigated pesticides activity 27 (Figure 15) have sufficient antibacterial activity against Xoo, Rs and Xac. Compound 27b at EC 50 of 9.1 μg/ml displayed a significant inhibitory effect against Xac, higher than standered bismertiazole (54.9 μg/ml).…”

“…In recent years, Oomycetes diseases produced phytosanitary problems such as rodents, fungi, bacteria, and mostly during the post‐harvest time. The growth rate in world agricultural production and crops have slowed down due to this oomycetes diseases [92] . Phytopathogenic bacteria cause significant agricultural problems as they affect nutritional and commercially important crops.…”

“…(2020) have been synthesized eight 2‐hydroxy‐chalcones that showed anti‐phytopathogenic excellent potency at concentration (EC 50 32.5 μg/ml of compound 26 (Figure 13) against growth of oomycete Phytophthora infectants. The Quantitative Structural Activity Analysis (QSAR) indicates that fluoride, hydroxyl and amino groups in the main chain of the chalcone increase anti‐oomycete activity [92] …”

Hydroxy Chalcones and Analogs with Chemopreventive Properties

“…Claisen–Schmidt condensation is a simple experimental reaction to obtain chalcones from substituted acetophenone and benzaldehyde derivatives [ 41 ]. Grinding [ 42 ], microwave [ 43 ], and ultrasound techniques [ 44 ] have been employed as well. The Witting, Friedel-Crafts acylation, and Julia–Kocienski olefination reactions represent other possible pathways for the synthesis of biologically active chalcones [ 45 ].…”