Synthesis, antioxidant and antimicrobial properties of novel pyridyl-carbonyl thiazoles as dendrodoine analogs

Abstract

Marine compound dendrodoine was first obtained from tunicate species ( Dendrodo grossularia ). It has a five-membered ring, namely, it is a heterocycle thiadiazole, which is found rarely in natural sources . Following its biological activities, novel analogs have been investigated recently. Synthesis of the analogs for this study is realized with uncommon thiazole closure, including methylene-carbonyl condensation. Structures are elucidated by NMR ( 1 , 13 C) and HRMS spectrums. As an alkaloid derivative, antioxidant properties were evaluated with DPPH and FRAP assays and antimicrobial effect with microdilution method. Among the series, 3bc-3cf showed higher antioxidant activity than those having 3 or 4-pyridyl substituents. There is lesser activity for 2-pyridyl activity for 2-pyridyl containing group, which may be a result of intramolecular interactions. No activity was observed against gram-negative bacteria at 250 μg/mL. 3ae and 3ce showed activity at 64 μg/mL against S. aureus and 3ae showed activity at 16 μg/mL against S. epidermidis gram-positive bacteria. Chloramphenicol showed activity against all microorganisms at 8–16 μg/mL. Sixteen original dendrodoine analogs have been defined by close/higher activity compared to dendrodoine analogs and Trolox.

Sulfilimine bond formation in collagen IV

“…This is considered one of the earliest examples of a synthetically created N–S bond-containing natural product known for its antioxidant and antimicrobial properties. 68 More recently, in 2023, Huang et al 69 developed a metal-free and redox-neutral strategy for the selective S -alkylation of sulfenamides under basic conditions, resulting in the formation of sulfilimines. Their study involved resonance between bivalent nitrogen-centered anions, generated after deprotonation of sulfenamides under alkaline conditions, and sulfinimidoyl anions.…”