Tautomeric-Dependent Lactam Cycloaddition with Nitrile Oxide: Facile Synthesis of 1,2,4-Oxadiazole[4,5-a]indolone Derivatives.
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ABSTRACT:
SUBMITTER: Jiang KM
PROVIDER: S-EPMC6044867 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:1,2,4-Oxadiazole[4,5-a]piridinium chloride adds nucleophiles to undergo electrocyclic ring opening affording 1,2,4-oxadiazole dienamino derivatives. These pyridinium salts represent a special class of Zincke salts that are prone to rearrange when treated with primary amines or in the presence of bicarbonate to give the pyridones. The pivotal tuning of the experimental conditions leads to a straightforward synthesis of valuable 1,2,4-oxadiazole dienamine derivatives. The mechanism is also discussed in the light of NMR experiments and theoretical calculations.
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Project description:BackgroundPlant diseases seriously threaten food security, it is urgent to discover efficient and low-risk chemical pesticides. 1,2,4-Oxadiazole derivatives exhibit broad spectrum of agricultural biological activities. For discovering novel molecules with excellent agricultural activities, novel 1,2,4-oxadiazole derivatives were synthesized and evaluated for their agricultural activities.ResultBioassays results showed that the title compounds exhibited moderate nematocidal activity against Meloidogyne incognita and anti-fungal activity to Rhizoctonia solani. It's worth noting that compounds 5m, 5r, 5u, 5v, 5x and 5y showed strong antibacterial effects on Xanthomonas oryzae pv. oryzae (Xoo), with EC50 values of 36.25, 24.14, 28.82, 19.44, 25.37 and 28.52 ?g/mL, respectively, superior to bismerthiazol (BMT, EC50?=?77.46 ?g/mL) and thiodiazole copper (TDC, EC50?=?99.31 ?g/mL). Compounds 5p, 5u and 5v exhibited excellent antibacterial ability against Xanthomonas oryzae pv. oryzicola (Xoc), with EC50 values of 31.40, 19.04 and 21.78 ?g/mL, respectively, better than that of BMT (EC50?=?68.50 ?g/mL) and TDC (EC50?=?91.05 ?g/mL). In addition, compound 5v exerted moderate antibacterial effects on rice bacterial leaf blight.ConclusionsTwenty-six novel 1,2,4-oxadiazole derivatives were obtained and their biological activities were evaluated. Compound 5u and 5v exhibited excellent antibacterial activity Xoo and Xoc. These results indicated that 1,2,4-oxadiazole derivatives containing a trifluoromethyl pyridine moiety could be as potential alternative templates for discovering novel antibacterial agents.
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Project description:1,2,4-Oxadiazole[4,5-a]piridinium salts add alcohols and alkoxides to undergo electrocyclic ring opening affording alkoxybutadienyl 1,2,4-oxadiazole derivatives. The pyridinium salts represent a special class of Zincke salts that are prone to rearrange to give alkoxybutadienyl 1,2,4-oxadiazoles when treated with suitable nucleophiles or, alternatively, to give pyridones in the presence of bicarbonate. The pivotal tuning of the experimental conditions leads to a straightforward synthesis of valuable 1,2,4-oxadiazole derivatives. The mechanism is also discussed in the light of previous observations.
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Project description:Alzheimer's disease (AD) is a progressive mental disorder that brings a huge economic burden to the healthcare systems. During this illness, acetylcholine levels in the cholinergic systems gradually diminish, which results in severe memory loss and cognitive impairments. Moreover, Butyrylcholinesterase (BuChE) enzyme participates in cholinergic neurotransmission regulation by playing a prominent role in the latter phase of AD. In this study, based on donepezil, which is an effective acetylcholinesterase (AChE) inhibitor, a series of 1,2,4-oxadiazole compounds were designed, synthesized and their inhibitory activities towards AChE and BuChE enzymes were evaluated. Some structures exhibited a higher selectivity rate towards BuChE in comparison to donepezil. Notably, compound 6n with an IC50 value of 5.07 µM and an SI ratio greater than 19.72 showed the highest potency and selectivity towards BuChE enzyme. The docking result revealed that compound 6n properly fitted the active site pocket of BuChE enzyme, and formed desirable lipophilic interactions and hydrogen bonds. Moreover, according to in silico ADME studies, these compounds have proper potential for being developed as new oral anti-Alzheimer's agents (Figure 1(Fig. 1)).
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