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1.
J Agric Food Chem ; 68(7): 2116-2123, 2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-31986045

RESUMO

Fungal pathogens cause serious crop diseases and decrease crop yields and quality. Polyacetylene alcohols are plant secondary metabolites and bioactive against various pathogenic fungi. They are, however, difficult to synthesize. In the present study, an efficient and highly enantioselective method (>98% ee) was established and employed to achieve the synthesis of the natural C18 polyacetylenes (S,E)-octadeca-1,9-dien-4,6-diyn-3-ol 1, (3R,10R,E)-octadeca-1,8-dien-4,6-diyne-3,10-diol 2, and their analogs. The title compounds were structurally characterized and biologically evaluated for fungicidal activities. The compounds exhibited high potencies against eight pathogenic fungal species tested, such as Colletotrichum gloeosporioiles, Bipolaris sorokiniana, Fusarium graminearum, and Fusarium pseudograminearum, with half-maximum effective concentrations ranging from 8 to 425 µg/mL, being similar to those of the fungicide thiophanate-methyl (3-408 µg/mL). These compounds are potential natural fungicides and fungicide lead candidates for further structural and property improvements.


Assuntos
Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Polímero Poliacetilênico/química , Polímero Poliacetilênico/farmacologia , Colletotrichum/efeitos dos fármacos , Colletotrichum/crescimento & desenvolvimento , Fungicidas Industriais/síntese química , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Polímero Poliacetilênico/síntese química , Estereoisomerismo
2.
J Agric Food Chem ; 68(8): 2306-2315, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-31995378

RESUMO

Neocryptolepine is an alkaloid isolated from traditional African herbal medicine Cryptolepis sanguinolenta, and its broad spectrum of biological activities has been illuminated in past decades. In this study, neocryptolepine and its derivatives (1-49) were designed and synthesized from economical and readily available starting materials. Their structures were confirmed by proton nuclear magnetic resonance, carbon nuclear magnetic resonance, and mass spectrometry. The synthesized compounds were screened for their antifungal profile against six agriculturally important fungi Rhizoctonia solani, Botrytis cinerea (B. cinerea), Fusarium graminearum, Mycosphaerella melonis, Sclerotinia sclerotiorum, and Magnaporthe oryzae. The results of in vitro assay revealed that compounds 5, 21, 24, 35, 40, 45, and 47 presented remarkable antifungal activity against the fungi tested with EC50 values lower than 1 µg/mL. Significantly, compound 24 displayed the most effective inhibitory potency against B. cinerea (EC50 = 0.07 µg/mL), and the data from in vivo experiments revealed that compound 24 demonstrated comparable protective activity with the positive control boscalid. Preliminary mechanism studies indicated that compound 24 showed impressive spore germination inhibitory effectiveness and lower cytotoxicity than azoxystrobin, imparted on normal function of the cell membrane and cell wall, and arrested the normal function of the nucleus. Besides the excellent inhibitory activity against agriculturally important phytopathogenic fungi tested, the designed assemblage possesses several benefits with a high profile of variation in synthesized molecules, the ease of synthesis, and good cost-effectiveness of commercially available synthetic reagents, all of these have highlighted the potential worth of compound 24 as a new and highly efficient agricultural fungicide.


Assuntos
Antifúngicos/farmacologia , Fungicidas Industriais/farmacologia , Doenças das Plantas/microbiologia , Antifúngicos/síntese química , Antifúngicos/química , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Fungicidas Industriais/síntese química , Fungicidas Industriais/química , Fusarium/efeitos dos fármacos , Fusarium/crescimento & desenvolvimento , Estrutura Molecular , Rhizoctonia/efeitos dos fármacos , Rhizoctonia/crescimento & desenvolvimento , Relação Estrutura-Atividade
3.
J Agric Food Chem ; 67(50): 13904-13913, 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31765135

RESUMO

A series of N-aryl-pyridine-4-one derivatives were designed and synthesized using maltol and antidesmone as lead compounds, and then their fungicidal/bactericidal activities and possible mechanism of action against Colletotrichum musae were explored. Most of these compounds exhibited significant fungicidal activity in vitro. Especially, compound 23 has more than 90% inhibitory activity against nine plant pathogenic fungi at 50 µg mL-1, which is superior to azoxystrobin. Moreover, an in vivo bioassay also demonstrated that compound 23 exhibited high-efficiency broad-spectrum antifungal activity and can effectively control postharvest diseases of mango. In addition, it was found that compounds 22 and 23 can also effectively control rice bacterial leaf blight in pot experiments, which was even more effective than zhongshengmycin. Preliminary mechanism studies revealed that compound 23 may cause cell membrane and mitochondria destruction. These findings indicate that compound 23 can be used to develop potential agrochemical fungicides and bactericides.


Assuntos
Agroquímicos/química , Agroquímicos/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Agroquímicos/síntese química , Colletotrichum/efeitos dos fármacos , Fungicidas Industriais/síntese química , Mangifera/microbiologia , Estrutura Molecular , Oryza/microbiologia , Doenças das Plantas/microbiologia , Piridinas/química , Piridinas/farmacologia , Rhizoctonia , Relação Estrutura-Atividade , Xanthomonas/efeitos dos fármacos , Xanthomonas/crescimento & desenvolvimento
4.
J Agric Food Chem ; 67(47): 13185-13194, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31697490

RESUMO

In searching for novel fungicidal leads, the novel bioactive succinate dehydrogenase inhibitor (SDHI) derivatives were designed and synthesized by the inversion of carbonyl and amide groups. Bioassay indicated that compound 5i stood out with a broad spectrum of in vitro activity against five fungi. Its EC50 value (0.73 µg/mL) was comparable to that of boscalid (EC50 of 0.51 µg/mL) and fluxapyroxad (EC50 of 0.19 µg/mL) against Sclerotinia sclerotiorum. For Rhizoctonia cerealis, 5i and 5p with EC50 values of 4.61 and 6.48 µg/mL, respectively, showed significantly higher activity than fluxapyroxad with the EC50 value of 16.99 µg/mL. In vivo fungicidal activity of 5i exhibited an excellent inhibitory rate (100%) against Puccinia sorghi at 50 µg/mL, while the positive control boscalid showed only a 70% inhibitory rate. Moreover, 5i showed promising fungicidal activity with a 60% inhibitory rate against Rhizoctonia solani at 1 µg/mL, which was better than that of boscalid (30%). Compound 5i possessed better in vivo efficacy against P. sorghi and R. solani than boscalid. Molecular docking showed that even the carbonyl oxygen atom of 5i was far from the pyrazole ring. It could also form hydrogen bonds toward the hydroxyl hydrogen and amino hydrogen of TYR58 and TRP173 on SDH, respectively, which consisted of the positive control fluxapyroxad. Fluorescence quenching analysis and SDH enzymatic inhibition studies also validated its mode of action. Our studies showed that 5i was worthy of further investigation as a promising fungicide candidate.


Assuntos
Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Proteínas Fúngicas/antagonistas & inibidores , Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Succinato Desidrogenase/antagonistas & inibidores , Ascomicetos/química , Ascomicetos/efeitos dos fármacos , Ascomicetos/enzimologia , Inibidores Enzimáticos/química , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Fungicidas Industriais/química , Simulação de Acoplamento Molecular , Rhizoctonia/química , Rhizoctonia/efeitos dos fármacos , Rhizoctonia/enzimologia , Relação Estrutura-Atividade , Succinato Desidrogenase/química , Succinato Desidrogenase/metabolismo
5.
J Agric Food Chem ; 67(45): 12357-12365, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31596575

RESUMO

A series of isothiazole, 1,2,3-thiadiazole, and thiazole-based cinnamamide morpholine derivatives were rationally designed, synthesized, characterized, and evaluated for their fungicidal activities. Bioassay indicated that a combination of 3,4-dichloroisothiazole active substructures with cinnamamide morpholine lead to significant improvement of in vivo antifungal activities of the target compounds; among them, compound 5a exhibited good fungicidal activity against Pseudoperonspera cubensis in vivo with an inhibition rate of 100% at 100 µg/mL. A field experiment indicated that the difference of efficacy between 5a (75.9%) and dimethomorph (77.1%) at 37.5 g ai/667 m2 was not significant; and 5a also exhibited good activity against Botrytis cinerea by triggering accumulation of PAL and NPR1 defense-related gene expression and the defense associated enzyme phenylalanine ammonia-lyase (PAL) expression on cucumber, rather than direct inhibition. These findings strongly supported that 3,4-dichloroisothiazole containing cinnamamide morpholine 5a not only showed good fungicidal activity against P. cubensis but also exhibited plant innate immunity stimulation activity as a promising fungicide candidate with both fungicidal activity and systemic acquired resistance.


Assuntos
Cinamatos/química , Fungicidas Industriais/síntese química , Tiadiazóis/química , Tiazóis/química , Botrytis/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Cinamatos/farmacologia , Cucumis sativus/efeitos dos fármacos , Cucumis sativus/genética , Cucumis sativus/metabolismo , Cucumis sativus/microbiologia , Descoberta de Drogas , Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Estrutura Molecular , Doenças das Plantas/microbiologia , Relação Estrutura-Atividade , Tiadiazóis/farmacologia
6.
J Agric Food Chem ; 67(41): 11340-11353, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31532201

RESUMO

Inspired by quinine and its analogues, we designed, synthesized, and evaluated two series of quinoline small molecular compounds (a and 2a) and six series of quinoline derivatives (3a-f) for their antifungal activities. The results showed that compounds 3e and 3f series exhibited significant fungicidal activities. Significantly, compounds 3f-4 (EC50 = 0.41 µg/mL) and 3f-28 (EC50 = 0.55 µg/mL) displayed the superior in vitro fungicidal activity and the potent in vivo curative effect against Sclerotinia sclerotiorum. Preliminary mechanism studies showed that compounds 3f-4 and 3f-28 could cause changes in the cell membrane permeability, accumulation of reactive oxygen species, loss of mitochondrial membrane potential, and effective inhibition of germination and formation of S. sclerotiorum sclerotia. These results indicate that compounds 3f-4 and 3f-28 are novel potential fungicidal candidates against S. sclerotiorum derived from natural products.


Assuntos
Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Quinina/farmacologia , Quinolinas/farmacologia , Ascomicetos/efeitos dos fármacos , Produtos Biológicos/química , Desenho de Fármacos , Fungicidas Industriais/química , Estrutura Molecular , Quinina/química , Quinolinas/química , Relação Estrutura-Atividade
7.
J Agric Food Chem ; 67(41): 11354-11363, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31532666

RESUMO

A series of dehydrozingerone derivatives were synthesized, and their fungicidal activities and action mechanism against Colletotrichum musae were evaluated. The bioassay result showed that most compounds exhibited excellent fungicidal activity in vitro at 50 µg mL-1. Compounds 13, 16, 18, 19, and 27 exhibited broad-spectrum fungicidal activity; especially, compounds 19 and 27 were found to have more potent fungicidal activity than azoxystrobin. The EC50 values of compounds 19 and 27 against Rhizoctonia solani were 0.943 and 0.161 µg mL-1 respectively. Moreover, compound 27 exhibited significant in vitro bactericidal activity against Xanthomonas oryzae pv. oryzae, with an EC50 value of 11.386 µg mL-1, and its curative effect (49.64%) and protection effect (51.74%) on rice bacterial blight disease was equivalent to that of zhongshengmycin (42.90%, 40.80% respectively). Compound 27 could also effectively control gray mold (87.10%, 200 µg mL-1) and rice sheath blight (100%, 200 µg mL-1; 82.89%, 100 µg mL-1) in vivo. Preliminary action mechanism study showed that compound 27 mainly acted on the cell membrane and significantly inhibited ergosterol biosynthesis in Colletotrichum musae.


Assuntos
Ergosterol/antagonistas & inibidores , Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Estirenos/síntese química , Estirenos/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Colletotrichum/efeitos dos fármacos , Colletotrichum/metabolismo , Ergosterol/biossíntese , Fungicidas Industriais/química , Testes de Sensibilidade Microbiana , Estrutura Molecular , Oryza/microbiologia , Doenças das Plantas/microbiologia , Rhizoctonia/efeitos dos fármacos , Rhizoctonia/metabolismo , Relação Estrutura-Atividade , Estirenos/química , Xanthomonas/efeitos dos fármacos , Xanthomonas/metabolismo
8.
Molecules ; 24(17)2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-31470567

RESUMO

BACKGROUND: The development of new antifungal agents has always been a hot research topic in pesticide development. In this study, a series of derivatives of natural compound ß-pinene were prepared, and the antifungal activities of these derivatives were evaluated. The purpose of this work is to develop some novel molecules as promising new fungicides. METHODS: Through a variety of chemical reactions, ß-pinene was transformed into a series of ß-pinene-based derivatives containing amide moieties and acylthiourea moieties. The antifungal activities of these derivatives against five plant pathogens including Colletotrichum gloeosporioides, Fusarium proliferatum, Alternaria kikuchiana, Phomopsis sp. and Phytophthora capsici were tested; preliminary structure-activity relationship was discussed. RESULTS: Some derivatives exhibited moderate or significant antifungal activity due to the fusion of the amide moiety or the acylthiourea moiety with the pinane skeleton. The structure-activity relationship analysis showed that the fluorine atom and the strong electron withdrawing nitro group, or trifluoromethyl group on the benzene ring of the derivatives had a significant effect on the improvement of the antifungal activity against Colletotrichum gloeosporioides, Fusarium proliferatum, Alternaria kikuchiana and Phomopsis sp. Meanwhile, the introduction of an ethyl group at the meta-position on the benzene ring of the derivatives could improve the antifungal activity against Phytophthora capsici. Compounds 4e, 4h, 4q, 4r exhibited broad-spectrum antifungal activity against the tested strains. Compound 4o had significant antifungal activity against Phytophthora capsici (IC50 = 0.18 µmol/L). These derivatives were expected to be used as precursor molecules for novel pesticide development in further research.


Assuntos
Alternaria/efeitos dos fármacos , Colletotrichum/efeitos dos fármacos , Fungicidas Industriais/síntese química , Fusarium/efeitos dos fármacos , Phytophthora/efeitos dos fármacos , Sordariales/efeitos dos fármacos , Alternaria/crescimento & desenvolvimento , Amidas/química , Colletotrichum/crescimento & desenvolvimento , Fungicidas Industriais/farmacologia , Fusarium/crescimento & desenvolvimento , Testes de Sensibilidade Microbiana , Phytophthora/crescimento & desenvolvimento , Doenças das Plantas/microbiologia , Doenças das Plantas/terapia , Plantas/microbiologia , Sordariales/crescimento & desenvolvimento , Relação Estrutura-Atividade , Tioureia/química
9.
J Agric Food Chem ; 67(40): 11018-11024, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31512873

RESUMO

In this study, nine pyrimethanil ionic liquids (PILs) were synthesized through an acid-base reaction with nine naturally derived organic acid anions to improve the physicochemical properties and reduce the environmental adverse impacts. The PILs presented lower volatilization, higher photostability, better soil adsorption capacity, and improved fungicidal activity relative to pyrimethanil. When the length of the carbon chains in the anions was increased, the PILs showed better properties in terms of melting point, water solubility, volatility, and surface tension. The photostabilities and fungicidal activities of the PILs were significantly improved when cyclic compounds were used as the paired anion ions. With enhanced physicochemical properties and better fungicidal activity, PIL7 was selected as the best alternative to pyrimethanil. The intrinsic disadvantages of pyrimethanil could be surmounted using the system developed in the study; thus, ILs could have immense potential in the development of eco-friendly and efficient fungicides in the future.


Assuntos
Fungicidas Industriais/química , Líquidos Iônicos/química , Compostos Orgânicos/química , Pirimidinas/química , Adsorção , Ânions/química , Ânions/farmacologia , Fungos/efeitos dos fármacos , Fungos/crescimento & desenvolvimento , Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Líquidos Iônicos/farmacologia , Cinética , Compostos Orgânicos/farmacologia , Pirimidinas/farmacologia , Solo/química , Solubilidade , Volatilização
10.
J Agric Food Chem ; 67(43): 11893-11900, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31542926

RESUMO

To explore a novel fungicide effectively against cucumber downy mildew (CDM), a series of new arylpyrazole containing pyrimidine ether derivatives were designed and synthesized by employing the intermediate derivatization method (IDM). The structures of synthesized compounds were identified by 1H NMR, 13C NMR, elemental analyses, MS, and X-ray diffraction. Bioassays demonstrated that some of the title compounds exhibited excellent fungicidal activities against CDM. Especially, compound 7 (EC50 = 1.22 mg/L) displayed significantly higher bioactivity than that of commercial fungicides diflumetorim and flumorph and nearly equal effect to that of cyazofamid. The relationship between the structure and fungicidal activity of the synthesized compounds was discussed as well. The study showed that compound 7 was a promising fungicide candidate for further development.


Assuntos
Éteres/química , Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Pirimidinas/química , Cucumis sativus/microbiologia , Desenho de Fármacos , Éteres/farmacologia , Fungicidas Industriais/química , Estrutura Molecular , Oomicetos/efeitos dos fármacos , Doenças das Plantas/microbiologia , Pirimidinas/farmacologia , Relação Estrutura-Atividade , Difração de Raios X
11.
J Agric Food Chem ; 67(36): 10018-10031, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31448918

RESUMO

Plant diseases seriously endanger plant health, and it is very difficult to control them. A series of nortopsentin analogues were designed, synthesized, and evaluated for their antiviral activities and fungicidal activities. Most of these compounds displayed higher antiviral activities than ribavirin. Compounds 1d, 1e, and 12a, with excellent antiviral activities, emerged as novel antiviral lead compounds, among which 1e was selected for further antiviral mechanism research. The mechanism research results indicated that these compounds may play an antiviral role by aggregating viral particles to prevent their movement in plants. Further fungicidal activity tests revealed that nortopsentin analogues displayed broad-spectrum fungicidal activities. Compounds 2p and 2f displayed higher antifungal activities against Alternaria solani than the commercial fungicides carbendazim and chlorothalonil. Current research has laid a foundation for the application of nortopsentin analogues in plant protection.


Assuntos
Antivirais/farmacologia , Fungicidas Industriais/farmacologia , Oxazóis/farmacologia , Tiazóis/farmacologia , Alternaria/efeitos dos fármacos , Alternaria/crescimento & desenvolvimento , Antivirais/síntese química , Antivirais/química , Desenho de Fármacos , Fungicidas Industriais/síntese química , Fungicidas Industriais/química , Oxazóis/química , Relação Estrutura-Atividade , Tiazóis/química , Vírus do Mosaico do Tabaco/efeitos dos fármacos , Vírus do Mosaico do Tabaco/crescimento & desenvolvimento
12.
Molecules ; 24(14)2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31319619

RESUMO

In order to explore more efficient sulfonamides against Botrytis cinereal, 36 novel cyclohexylsulfonamides were synthesized by N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDCI) and 1-hydroxybenzotriazole (HOBt) condensation reaction using chesulfamide as a lead compound, introducing thiazole and pyrazole active groups. Their structures were characterized by 1H-NMR, 13C-NMR, mass spectrum (MS), and elemental analysis. Compound III -31 was further confirmed by X-ray single crystal diffraction. The in vitro and in vivo fungicidal activities against B. cinerea were evaluated by three bioassay methods. The results of mycelial growth demonstrated that median effective concentration (EC50) values of nine compounds were close to boscalid (EC50 = 1.72 µg/mL) and procymidone (EC50 = 1.79 µg/mL) against B. cinerea (KZ-9). In the spore germination experiment, it was found that compounds III-19 and III-31 inhibited germination 93.89 and 98.00%, respectively; at 10 µg/mL, they approached boscalid (95.97%). In the tomato pot experiment, the control effects of two compounds (III-21 and III-27) were 89.80 and 87.90%, respectively, at 200 µg/mL which were significantly higher than boscalid (81.99%). The structure-activity relationship (SAR) was also discussed, which provided a valuable idea for developing new fungicides.


Assuntos
Botrytis/efeitos dos fármacos , Fungicidas Industriais/química , Sulfonamidas/química , Botrytis/patogenicidade , Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Relação Estrutura-Atividade , Sulfonamidas/síntese química , Sulfonamidas/farmacologia , Tiazóis/síntese química , Tiazóis/química
13.
Pest Manag Sci ; 75(11): 2892-2900, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31050111

RESUMO

BACKGROUND: In recent years, carboxamide fungicides, targeting succinate dehydrogenase (SDH), have shown highly efficient and broad spectrum fungicidal activity. Structure-activity relationship (SAR) results for these commercial fungicides show that the carboxamide group was a key active group. This is useful information for the discovery of new pyrazole carboxamide derivatives with fungicidal activity. RESULTS: Twenty-seven novel pyrazole carboxamides were designed and synthesized. Their fungicidal activities against Gibberella zeae, Phytophthora infestans, Phytophthora capsici, Rhizoctonia solani, Alternaria solani, Botrytis cinerea, Fusarium oxysporum, Cercospora arachidicola, Sclerotinia sclerotiorum and Physalospora piricola were tested; derivatives possessed excellent inhibitory at 50 mg L-1 in particular. Furthermore, some pyrazole carboxamides exhibited remarkably high activities against Sclerotinia sclerotiorum in vitro with EC50 values of 2.04 to 15.2 µg mL-1 . In addition, some compounds also exhibited high activities against Physalospora piricola, Cercospora arachidicola and Phytophthora capsici. Inhibition activities against SDH proved that the designed analogues were effective at the enzyme level. The SAR of these pyrazole carboxamides was studied by using the docking method. CONCLUSION: It is possible that pyrazole carboxamides, which exhibit good activity against Sclerotinia sclerotiorum, can be further optimized as a lead compounds of carboxamide fungicides. © 2019 Society of Chemical Industry.


Assuntos
Ascomicetos/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Fungos Mitospóricos/efeitos dos fármacos , Phytophthora infestans/efeitos dos fármacos , Pirazóis/farmacologia , Fungicidas Industriais/síntese química , Fungicidas Industriais/química , Pirazóis/síntese química , Pirazóis/química , Relação Estrutura-Atividade
14.
J Agric Food Chem ; 67(17): 5008-5016, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30977370

RESUMO

A series of novel N-(2-(phenylamino)-4-fluorophenyl)-pyrazole-4-carboxamides 1-15 and aromatic carboxamides with a diphenylamine scaffold 16-29 were designed, synthesized, and evaluated for their antifungal activities. In vitro experiments showed that compound 6 (EC50 = 0.03 mg/L) was superior to bixafen (EC50 = 0.04 mg/L) against Rhizoctoinia solani and compound 6 (IC50 = 1.41 mg/L) was close to bixafen (IC50 = 1.22 mg/L) against succinate dehydrogenase from R. solani. Additionally, in vivo pot experiments showed that compound 6 (EC50 = 1.93 mg/L) was better than bixafen (EC50 = 3.72 mg/L) and close to thifluzamide (EC50 = 1.83 mg/L) against R. solani. In vivo field trials showed that compound 6 at 200 g ai ha-1 had 64.10% control efficacy against rice sheath blight after 21 days with two sprayings, close to thifluzamide (71.40%). Furthermore, molecular docking showed that compound 6 anchors in the binding site of SDH.


Assuntos
Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Difenilamina/química , Desenho de Fármacos , Fungicidas Industriais/química , Simulação de Acoplamento Molecular , Estrutura Molecular , Oryza/microbiologia , Doenças das Plantas/microbiologia , Rhizoctonia/efeitos dos fármacos
15.
Pest Manag Sci ; 75(12): 3160-3166, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30941863

RESUMO

BACKGROUND: Strobilurin fungicides are some of the most potent and successful agrochemicals. However, continued use of traditional strobilurins has led to the emergence of fungicide-resistant biotypes. Thus, a supply of new strobilurin fungicides is highly valuable. In this study, a series of novel methoxyacrylate analogs containing a cyano-substituted hydrazine moiety as the side chain was synthesized and evaluated for their anti-plant pathogenic activities. RESULTS: Compounds 2-04, 2-05, 2-07 and 2-14 exhibited a relatively broad range of fungicidal activity. Compounds 2-04, 2-13 and 2-14 exhibited good fungicidal activity against Sclerotinia sclerotiorum with median effective concentrations (EC50 ) of 3.84, 3.50 and 3.80 µg mL-1 , respectively. Most of these compounds showed excellent inhibition of spore germination in Magnaporthe grisea at 25 µg mL-1 . Moreover, in an in vivo test, compounds 2-02, 2-04, 2-07 and 2-13 exhibited potent fungicidal activities against the tested plant diseases at 400 µg mL-1 . Notably, compound 2-07 showed comparable or better activity than the commercially positive controls, azoxystrobin and procloraz, against powdery mildew of cucumber and rice blast fungus in the field trails at the same application dosages. CONCLUSON: This study indicated that methoxyacrylate analogs containing a cyano-substituted hydrazone side chain can serve as potential fungicidal candidates for crop protection. © 2019 Society of Chemical Industry.


Assuntos
Acetatos , Ascomicetos/efeitos dos fármacos , Fungicidas Industriais , Magnaporthe/efeitos dos fármacos , Controle de Pragas , Acetatos/síntese química , Fungicidas Industriais/síntese química , Doenças das Plantas/prevenção & controle
16.
Pest Manag Sci ; 75(12): 3273-3281, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31006964

RESUMO

BACKGROUND: N-Pyridylpyrazole derivatives have received continuous attention in agrochemical research during the last decade owing to their remarkable insecticidal or fungicidal potentials. To look for novel heterocyclic agrochemicals for increasing production of agriculture, a series of novel α-aminophosphonate derivatives containing N-pyridylpyrazole moiety were synthesized. RESULTS: The structures of the title compounds were confirmed via melting point, IR, 1 H NMR, 13 C NMR, 31 P NMR, HRMS and elemental analysis. The single crystal structure of diethyl (3-bromo-1-(3-chloropyridin-2-yl)-1H-pyrazol-5-yl)(2,6-dimethylphenylamino)methylphosphonate (compound 12b) was first reported. Moreover, the bioassays displayed that the title compounds exhibited modest or weak insecticidal activities against oriental armyworm at 200 µg mL-1 . The first investigation on the fungicidal potential of chlorantraniliprole showed no significant activities towards the six tested fungi found in this study, however, most of the title compounds displayed apparent in vitro fungicidal activity against some plant fungi, in particular excellent activities towards Physalospora piricola. Compounds 11a and 11b had EC50 values of 18.8 and 17.4 µg mL-1 , respectively, which were comparable with that of fungicide control triadimefon (EC50  = 24.7 µg mL-1 ) against Physalospora piricola. In addition, some compounds exhibited modest in vivo control efficacy at 0.5 mg mL-1 towards Sclerotinia sclerotiorum (11b: 30.1(±1.8)%), Rhizoctonia cerealis (11a: 20.4(±2.1)%; 11b: 30.2(±2.2)%), and Erysiphe graminis (11a: 30.3(±1.8)%; 12d: 40.2(±0.9)%). CONCLUSION: Compounds 11a, 11b and 12d could be promising new lead structures for the development and discovery of novel fungicides towards Physalospora piricola and Erysiphe graminis. The structure-activity relationship (SAR) analysis provided useful guidance and new understanding for the design of novel pyridylpyrazole-containing agrochemicals. © 2019 Society of Chemical Industry.


Assuntos
Ascomicetos/efeitos dos fármacos , Basidiomycota/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Inseticidas/farmacologia , Mariposas/efeitos dos fármacos , Organofosfonatos/farmacologia , Animais , Fungicidas Industriais/síntese química , Inseticidas/síntese química , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , Mariposas/crescimento & desenvolvimento , Organofosfonatos/síntese química , Relação Estrutura-Atividade
17.
Magn Reson Chem ; 57(6): 285-293, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30632625

RESUMO

The quantitative structure-activity relationship models of 40 phenylhydrazine-substituted tetronic acid derivatives were established between the 1 H nuclear magnetic resonance (NMR) and 13 C NMR chemical shifts and the antifungal activity against Fusarium graminearum, Botrytis cinerea, Rhizoctonia cerealis, and Colletotrichum capsici. The models were validated by R, R2 , RA 2 , variance inflation factor, F, and P values testing and residual analysis. It was concluded from the models that the 13 C NMR chemical shifts of C8, C10, C7, and the 1 H NMR chemical shifts of Ha contributed positively to the activity against Fusarium graminearum, Botrytis cinerea, Colletotrichum capsici, and Rhizoctonia cerealis, respectively. The models indicated that decreasing the election cloud density of specific nucleuses in compounds, for example, by the substituting of electron withdrawing groups, would improve the antifungal activity. These models demonstrated the practical application meaning of chemical shifts in the quantitative structure-activity relationship study. Furthermore, a practical guide was provided for further structural optimization of the antifungal phenylhydrazine-substituted tetronic acid derivatives based on the 1 H NMR and 13 C NMR chemical shifts.


Assuntos
Fungicidas Industriais/síntese química , Furanos/síntese química , Espectroscopia de Ressonância Magnética/métodos , Fenil-Hidrazinas/síntese química , Ascomicetos/efeitos dos fármacos , Botrytis/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Furanos/farmacologia , Fusarium/efeitos dos fármacos , Estrutura Molecular , Fenil-Hidrazinas/farmacologia , Relação Quantitativa Estrutura-Atividade , Rhizoctonia/efeitos dos fármacos
18.
Pest Manag Sci ; 75(7): 1831-1846, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30636031

RESUMO

BACKGROUND: UK-2A is an antifungal antibiotic produced by Streptomyces sp. 517-02. Derivatization of its picolinamide OH to form the isobutyryl acetal led to the discovery of fenpicoxamid (InatreqTM active), which is currently under development as a fungicide by Dow AgroSciences LLC. This paper documents efforts to achieve additional efficacy enhancements through semi-synthetic modification of the benzyl substituent of the UK-2A macrocycle. RESULTS: Of 34 analogs prepared, the most active had mitochondrial electron transport IC50 values 1.5- to 3.7-fold higher than UK-2A (IC50 0.86 nM). The cyclohexyl analog (38, IC50 1.23 nM) was the most intrinsically active derivative, and inhibited in vitro growth of Zymoseptoria tritici (EC50 2.8 ppb) and Leptosphaeria nodorum (EC50 6.2 ppb) more strongly than UK-2A (EC50 5.3 and 11.3 ppb for Z. tritici and L. nodorum, respectively). Heterocyclic ring systems and polar linker functionalities resulted in substantial activity loss. Several analogs (20, 22, 23, 24, 36 and 38) translated Z. tritici in vitro growth inhibition activity to in planta disease control more effectively than did UK-2A, with log D being a key factor in this regard. CONCLUSIONS: UK-2A is amenable to further modification at the benzyl position on the macrocycle, which provides opportunities for manipulation of physical properties while retaining strong intrinsic and antifungal activity. © 2019 Society of Chemical Industry.


Assuntos
Ascomicetos/efeitos dos fármacos , Fungicidas Industriais/síntese química , Ustilago/efeitos dos fármacos , Complexo III da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Fungicidas Industriais/química , Fungicidas Industriais/farmacologia , Concentração Inibidora 50 , Lactonas/síntese química , Lactonas/química , Lactonas/farmacologia , Mitocôndrias , Piridinas/síntese química , Piridinas/química , Piridinas/farmacologia , Relação Estrutura-Atividade , Triticum/microbiologia
19.
Pest Manag Sci ; 75(4): 1123-1130, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30284404

RESUMO

BACKGROUND: Natural stilbenes (especially resveratrol and its derivatives) are well-known phytoalexins that are active against many plant diseases. However, oxidative degradation and low bioavailability limit their exogenous application as fungicides on crops. In this study, a new class of resveratrol-inspired thiophene-based stilbene derivatives bearing an 1,3,4-oxadiazole unit was synthesized and the derivatives' antifungal activities against phytopathogenic fungi were investigated. RESULTS: The results revealed that compounds 5h and 5j exhibited improved antifungal activity against Botrytis cinerea with median effective concentrations (EC50 ) of 168.5 and 155.4 µg mL-1 , respectively, which were superior to the EC50 of resveratrol (263.1 µg mL-1 ). Compound 5j was shown to effectively control disease development in B. cinerea-infected tomatoes in vivo. Notably, considerably abnormal mycelial morphology and increased cell membrane conductivity were observed in the presence of compound 5j. CONCLUSION: A new class of thiophene-containing stilbene derivatives was designed and synthesized. Bioassay results showed that compound 5j exhibited promising antifungal activity, suggesting practical potential for fungal disease control. © 2018 Society of Chemical Industry.


Assuntos
Botrytis/efeitos dos fármacos , Fungicidas Industriais/farmacologia , Phyllachorales/efeitos dos fármacos , Estilbenos/síntese química , Estilbenos/farmacologia , Fungicidas Industriais/síntese química , Testes de Sensibilidade Microbiana , Oxidiazóis/química , Tiofenos/química
20.
Mol Divers ; 23(3): 573-583, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30465251

RESUMO

A series of novel 2-(6-thioxo-1,3,5-thiadiazinan-3-yl)-N'-phenylacethydrazide derivatives were designed, synthesized and evaluated for their antifungal activities against Fusarium graminearum (Fg), Rhizoctonia solani (Rs), Botrytis cinerea (Bc) and Colletotrichum capsici (Cc). The bioassay results in vitro showed that most of the title compounds exhibited impressive antifungal activities against the above plant fungi. Particularly, the compounds 5c, 5f, 5g, 5i, 5m and 5p displayed desirable anti-Rs activities, with the corresponding EC50 values of 0.37, 0.32, 0.49, 0.50, 0.46 and 0.45 µg/mL, respectively, which are superior to the positive control carbendazim (0.55 µg/mL). Further in vivo bioassay results showed that the anti-Rs activity of title compound 5f at 200 µg/mL reached 95.84% on detached rice leaves and 93.96% on rice plants. Featuring convenient synthesis, novel structures and desirable antifungal activity, these 2-(6-thioxo-1,3,5-thiadiazinan-3-yl)-N'-phenylacethydrazide derivatives could be further studied as the potential candidates of novel agricultural fungicides.


Assuntos
Desenho de Fármacos , Fungicidas Industriais/síntese química , Fungicidas Industriais/farmacologia , Tiadiazinas/síntese química , Tiadiazinas/farmacologia , Técnicas de Química Sintética , Fungicidas Industriais/química , Testes de Sensibilidade Microbiana , Relação Estrutura-Atividade , Tiadiazinas/química
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