ABSTRACT
Sulfones are one of the most important classes of agricultural fungicides. To discover new lead compounds with high antibacterial activity, a series of new sulfone derivatives were designed and synthesized by introducing the aroxymethyl moiety into the scaffold of 1,3,4-oxadiazole/thiadiazole sulfones. Antibacterial activities against three phytopathogens (Xanthomonas oryzae pv. oryzae, Ralstonia solanacearum, Xanthomonas axonopodis pv. citri.) were assayed in vitro. As compared to the control of commercial fungicides and some reported sulfone fungicides, seven compounds 5I-1-5I-7 exerted remarkably higher activities with EC50 values ranging from 0.45-1.86 µg/mL against X. oryzae and 1.97-20.15 µg/mL against R. solanacearum. Exhilaratingly, 5I-1, 5I-2 and 5I-4 displayed significant in vivo activity against X. oryzae with protective effect of 90.4%, 77.7%, and 81.1% at 200 µg/mL, respectively, much higher than that exhibited by Bismerthiazol (25.6%) and Thiadiazole-copper (32.0%). And the differential phytotoxicity of active derivatives was preliminarily checked. The results demonstrated that derivative of 2-aroxymethyl-1,3,4-oxadiazole/thiadiazole sulfone can serve as potential alternative bactericides for the management of plant bacterial diseases.
Subject(s)
Anti-Bacterial Agents/pharmacology , Oxadiazoles/chemistry , Ralstonia solanacearum/drug effects , Sulfones/chemical synthesis , Sulfones/pharmacology , Thiadiazoles/chemistry , Xanthomonas/drug effects , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Drug Design , Microbial Sensitivity Tests , Plant Diseases/microbiology , Structure-Activity Relationship , Sulfones/chemistryABSTRACT
The reaction mechanism of the γ-carbon addition of enal to imine under oxidative N-heterocyclic carbene catalysis is studied experimentally. The oxidation, γ-carbon deprotonation, and nucleophilic addition of γ-carbon to imine were found to be facile steps. The results of our study also provide highly enantioselective access to tricyclic sulfonyl amides that exhibit interesting antimicrobial activities against X. oryzae, a bacterium that causes bacterial disease in rice growing.
Subject(s)
Aldehydes/chemistry , Anti-Infective Agents/chemistry , Heterocyclic Compounds/chemistry , Heterocyclic Compounds/pharmacology , Imines/chemistry , Methane/analogs & derivatives , Oryza/chemistry , Sulfonamides/chemistry , Sulfonamides/pharmacology , Methane/chemistry , Molecular Structure , Oxidation-Reduction , StereoisomerismABSTRACT
An efficient synthesis of highly functionalized chiral ß-amino ester derivatives containing benzothiophene and benzothiazole moieties is developed by a Mannich-type reaction using a cinchona alkaloid-derived thiourea catalyst. The desired products were obtained in good yields and high enantioselectivities (~86% yield, >99% ee) using to the optimized reaction conditions. The synthesized compounds were characterized by 1H-NMR, 13C-NMR, IR, and HREI-MS analyses. The bioassays identified that compound 5dr has excellent antifungal activity, with a 60.53% inhibition rate against F. oxysporum, higher than that of the commercial agricultural fungicide hymexazol, whose inhibition rate was 56.12%.
Subject(s)
Amino Acids/chemical synthesis , Antifungal Agents/chemical synthesis , Benzothiazoles/chemistry , Cinchona Alkaloids/chemistry , Thiophenes/chemistry , Thiourea/chemistry , Amino Acids/pharmacology , Antifungal Agents/pharmacology , Catalysis , Esters , Fusarium/drug effects , Fusarium/growth & development , Microbial Sensitivity Tests , Oxazoles/pharmacology , Stereoisomerism , Structure-Activity RelationshipABSTRACT
In this paper, a three-dimensional finite element analysis (FEA) model was created for bionic artificial joint with joint capsule. Finite element method (FEM) was used to calculate and simulate mechanics distribution of the joint capsule under different thickness of the joint capsule, different loading, and different angular displacements. The results of the simulation show that the maximum stress is created in the joint area between artificial joint capsule. And the effect of the thickness of the artificial joint capsule on the stress magnitude and distribution is depend on motion model. On standing situation, the maximum stress decreases with the increase of the thickness of joint capsule. However, on walking situation, the maximum stress increases with the increase of the thickness of joint capsule. Whatever conditions simulated, the maximum stress of the artificial joint capsule is not over the limit of the material strength (9.97 megapascals). All the large stress, which gained from the simulation under different situations, locates at the interface between the capsule and the artificial joint. This is because the artificial joint and the capsule transfer loading each other at the interface. At the same time, supporting area of the capsule at the location of the interface is minimum for the whole vesicle. The stress concentration is inevitable at the interface due to the model structure. This result will offer guidance for the optimum joint structure of the capsule and the artificial joint.
