Synthesis And Biological Activities Of Novel Tetramic Acid Derivatives Incorporating A Moiety Of Pyridine

Tenuazonic acid (TeA), as a secondary metabolites of Altemaria alternata (Fr.) Keissler, has anti-tumor and anti-virus activity. Especially its highly herbicidal activity has drawn wide attention. Massive derivatives of tetramic acid were synthesized by modifying the pyrrole ring, some of them showed significant biological activity. Pyridine is a common but important heterocyclic in organic synthesis, existing in the structures of almost all fields of pesticides. Pesticides containing pyridine ring are not only high efficient, low toxic and durable, but also environment friendly, meets the requirement and tendency of pesticide in the future. In this paper, with tetramic acid as a lead compound, pyridine was introduced to3-position of tetramic acid to synthesize4series of novel tetramic acid derivatives incorporating a moiety of pyridine for screening high active compounds.Firstly, eight intermediates of tetramic acid were synthetized, then4types of target compounds containing the structure of pyridine we synthetized including eleven (iso)nicotinic acid N’-(1-(2,4-dioxo-pyrrolidin-3-ylidene)ethyl)hydrazide derivatives, eight3-(1-(pyridin-3-ylamino)-ethylidene)pyrrolidine-2,4-dione derivatives, sixteen3-(1-(N-pyridin-4-ylmethylenehydrazino)-ethylidene)pyrrolidine-2,4-dione derivatives and five3-(1-(N’-(3-Chloro-pyridin-2-yl)-hydrazine)ethylidene)pyrrolidine-2,4-dione derivatives. The structures of these title compounds were confirmed by IR,1H NMR, MS and elemental analysis.The fungicidal activities of all title compounds against Fusarium gramineaum, Botrytis cinerea and Rhizoctorzia solani were evaluated by mycelial growth rate method. The results indicated that most compounds show certain fungicidal activities at a concentration of100μg/mL. Thereinto, the inhibitory rates of compounds10c and10d against Botrytis cinerea were more than62%. And the inhibitory rates of compounds10a and10b against Rhizoctorzia solani were58.5%and62.8%respectively.The herbicidal activities of all title compounds against Echinochloa crusgalli and Brassica napus were evaluated using palting procedure at a concentration of100μg/mL. The results showed that most compounds exibited a certain herbicidal activities. The inhibition to the root of Brassica campestris L performance better. Thereinto, the inhibitory rates of compounds9d,10a,10b,10c and10d against Brassica napus were72.0%,88.7%,89.3%,70.4and90.1%respectively. The inhibitory rates of compounds10a and10b against the root of Echinochloa crusgalli were72.0%and75.0%respectively.All title compounds have no obvious activity against the third instar larvae of Plutella xylostell at a concentration of100μg/mL evaluated by feeding dipped-leaf method.