Microwave assisted synthesis, characterization and biological activities of ferrocenyl chalcones and their QSAR...

A series of ferrocenyl chalcones using acetylferrocene, with ferrocenyl group at the keto carbonyl group, and different aldehydes were synthesized and their bioefficacy evaluation was done against Sclerotium rolfsii, Alternaria solani and Meloidogyne incognita. In continuation of our quest for potent crop protection products, in the present study, a series of 18 substituted ferrocenyl chalcones were synthesized in which ferrocenyl group was attached to the aldehyde moiety, using ferrocenecarboxyaldehyde and different acetophenones by microwave method (MM) and conventional method (CM) [cf: MM 1 to 5 min; CM 12-40 h] and characterized by various techniques viz. IR, LC-HRMS, ¹H-NMR and ¹³C-NMR. In vitro fungicidal activity showed that compound, (2E)-1-(5-Chloro-2-hydroxyphenyl)-3-ferrocenyl-prop-2-en-1-one (34) (ED₅₀ = 21.50 mg L^-1) was found to be most active against S. rolfsii and compound, (2E)-1-(4-Bromophenyl)-3-ferrocenyl-prop-2-en-1-one (21) (ED₅₀ = 31.14 mg L^-1) showed highest activity against A. solani. As regards nematicidal activity, compound (2E)-1-(3-Bromophenyl)-3-ferrocenyl-prop-2-en-1-one (29) was more potent with LC₅₀ values of 11.95, 8.07 and 4.34 mg L^-1 at 24, 48 and 72 h, respectively. QSAR study revealed that MLR for S. rolfsii (r ² = 0.9834, q ²= 0.8975) and A. solani (r ² = 0.9807, q ²= 0.8713) and PLS for M. incognita (r ² = 0.9023, q ²= 0.7818) were the best models.