title: Synthesis of 4-methyl-1,2,3-thiadiazole derivatives via Ugi reaction and their biological activities.
abstract: The Ugi reaction is a green and rapid one-pot reaction for lead derivation. To develop novel candidate pesticides with diverse biological activities, two series of 4-methyl-1,2,3-thiadiazole derivatives containing active substructures of 3-chloro-4-methylphenyl or 3-fluoro-4-methylphenyl, respectively, were rationally designed and synthesized via Ugi reaction according to the principle of combinations of bioactive substructures. All of the structures of newly synthesized compounds were confirmed by proton nuclear magnetic resonance and high-resolution mass spectrometry. Biological activities of the target compounds including fungicide activity, antivirus activity in vitro and in vivo, and systemic acquired resistance were evaluated systematically. The results indicated that derivatives containing 3-(trifluoromethyl)phenyl and 2-methylphenyl possessed a potential wide spectrum of fungicidal activity. Derivatives containing 3-(trifluoromethyl)phenyl and 4-hydroxyphenyl possessed good potential direct antivirus activities against tobacco mosaic virus (TMV) in vitro, and the replacement of Cl atom by F atom improved their direct inhibition activities against TMV in vitro. Derivatives containing phenyl, 2-(trifluoromethyl)phenyl, 3-(trifluoromethyl)phenyl, 3-nitrophenyl, 4-nitrophenyl, 2-methylphenyl, and 4-hydroxyphenyl possessed good potential bioactivities in vivo including protection, inactivation, curative, and induction activities against TMV. These studies indicate that the newly synthesized 4-methyl-1,2,3-thiadiazole derivatives possessed good potential bioactivities, and a combination of bioactive substructures via Ugi reaction was an effective way to find bioactive compounds for novel pesticide development.
authors.affiliation: State Key Laboratory of Elemento-Organic Chemistry, Nankai University, No. 94, Weijin Road, Nankai District, Tianjin 300071, People's Republic of China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zuo
authors.forename: Na
authors.initials: N
authors.lastname: Mi
authors.forename: Zhijin
authors.initials: Z
authors.lastname: Fan
authors.forename: Qingxiang
authors.initials: Q
authors.lastname: Zheng
authors.forename: Haike
authors.initials: H
authors.lastname: Zhang
authors.forename: Huan
authors.initials: H
authors.lastname: Wang
authors.forename: Zhikun
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000998:Antiviral Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D017550:Spectroscopy, Fourier Transform Infrared; D013830:Thiadiazoles / Q000138:chemical synthesis* / Q000494:pharmacology*
chemical_list: D000998:Antiviral Agents; D013830:Thiadiazoles