Discovery of a new fungicide by screening triazole sulfonylhydrazone derivatives and its downy mildew inhibition in cucumber

Downy mildew is a very important detrimental disease that lead reduced to fruits and vegetables. Due to the continuous growth of drug resistance, finding novel fungicides with dissimilar modes of function from present fungicides for controlling downy mildew are imminent. This work is an extension of our preceding research on the original triazole sulfonamide derivatives lead compound. Triazole sulfonamide as a remarkable nitrogen-containing heterocyclic compound opposed cucumber downy mildew (CDM) develops a quite vital part in the sphere of the study of new farm chemicals. The existing report designs a certain amount of 1,2,4-triazole-1,3-disulfonamide derivatives. Hydrazones have obtained extensive attention in the field of pharmaceutical due to its unique chemical structure and remarkable activity (insecticidal, antibacterial, antifungal and herbicidal). By means of coupling numerous hydrazone with triazole sulfonyl chloride groups, 24 novel derivatives were synthesized. Spectrum analysis of LC-MS, ¹H NMR and ¹³C NMR were used for characterizing these new compounds. Compared with commercial Cyazofamid using bioassays, most of these compounds displayed preferable fungicidal activities. Moreover, compounds 8q illustrated the greatest CDM resistance (EC₅₀ = 7.776 mg/L). Field efficacy trials revealed that compound 8q fungicidal activity was higher than the purchased agrochemical Cyazofamid and Amisulbrom. Thus, the research declared that 8q displayed a great potential for the application of fungicide against CDM.     

Design,Synthesis and Biological Evaluation of Isothiazole Based 1,2,4‐Trizaole Derivatives

A series of novel 3,4‐dichloroisothiazole based 1,2,4‐triazole derivatives were rationally designed and synthesized. Their structures were confirmed by ¹H NMR, ¹³C NMR, HRMS or elemental analysis; the typical crystal structure was determined by X‐ray diffraction for validation. All target compounds were evaluated for their in vitro fungicidal and in vivo anti‐TMV activities. The bioassay results indicated that compound 6b , namely 1‐(3,4‐dichloroisothiazol‐5‐yl)‐1‐(4‐fluorophenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)ethanol, exhibited excellent growth inhibition against B. cinerea, C. arachidicola and P. piricola with median effective concentrations (EC₅₀) of 6.98, 2.73 and 3.07 μg/mL, respectively, and good in vivo anti‐TMV activity of over 60% of inactivation and induction activity at 100 μg/mL. These data demonstrate that compound 6b is both a fungicide and an anti‐TMV lead, deserving further studies.     

Design,Synthesis, and Antifungal Activities of New β‐Methoxyacrylate Analogues

Strobilurins have become one of the most important classes of agricultural fungicides. To search for new strobilurin derivatives with high activity against resistant pathogens, a series of new β‐methoxyacrylate analogues containing substituted pyrimidine in the side chain with strobilurin pharmacophore were synthesized and their biological activities were tested. The compounds were confirmed and characterized by ¹H‐NMR, elemental analysis and mass spectroscopy. The bioassays indicated that most of the compounds 1 exhibited potent antifungal activities against Colletotrichum orbiculare, Botrytis cinerea Pers and Phytophthora capsici Leonian at a concentration of 50 μg mL^?1. Notably, compound 1b (R = 2,5‐dimethylphenyl) showed better antifungal activity against all the tested fungi than the commercial strobilurin fungicide azoxystrobin.     

Synthesis and Biological Activity of Novel Furan/Thiophene and Piperazine‐Containing (Bis)1,2,4‐triazole Mannich Bases

Series of novel furan/thiophene and piperazine‐containing 1,2,4‐triazole Mannich bases and bis(1,2,4‐triazole) Mannich bases have been conveniently synthesized via Mannich reaction with triazole Schiff bases, various piperazine derivatives, and formaldehyde as intermediates in good yields. Their structures were characterized by melting points, ¹H NMR, ¹³C NMR, IR and elemental analysis. The preliminary bioassay showed that most compounds exhibited significant in vitro and in vivo fungicidal activity against several test plant fungi. Among 32 new compounds, the trifluoromethyl‐containing compounds showed superior activity than the methyl‐containing ones. Several compounds, such as F8 , F9 , F10 , G5 , H7 , H8 , I3 and I4 , were comparable with some commercial fungicides against different fungi during the present study and could be further structurally optimized. Meanwhile, several compounds showed good herbicidal activity against Brassica campestris at 100 µg/mL and KARI inhibitory activity at 200 µg/mL. However, compounds exhibited poor insecticidal activity against oriental armyworm at 200 µg/mL in the preliminary studies. The research results will provide useful information for the design and discovery of new agrochemicals with novel heterocyclic structures.     

Synthesis and Fungicidal Activities of 2,3‐Dimethyl‐4‐(1‐acyloxy)alkoxy‐6‐tert‐butyl‐8‐fluoroquinolines

A series of 2,3‐dimethyl‐4‐(1‐acyloxy)alkoxy‐6‐tert‐butyl‐8‐fluoroquinolines were synthesized by 4‐(tert‐butyl)aniline as the starting material via acylation, substitution, and hydrolysis, and their structures were characterized by ¹H NMR, ¹³C NMR, and HRMS. The fungicidal activity showed that compounds 6c , 6e , and 6f had excellent activity against Sphoaerotheca fuliginea with EC₅₀ values of 38.62, 6.77, and 50.35 mg/L, respectively. The results suggest that this chemotype of compounds warrant further studies as promising fungicide.     

4,5-二氢-1,2,4-三唑-5-硫酮席夫碱的合成和生物活性

以4-氨基-4,5-二氢-3-苯氧甲基-1氢-1,2,4-三唑-5-硫酮与取代苯甲醛为原料反应制得了9个新的三唑硫酮席夫碱类化合物,经IR、1H NMR和元素分析确定了各化合物结构。初步室内毒力测试结果表明该类化合物其具有较好的杀菌活性。     

Synthesis and Fungicidal Activity of Strobilurin Analogues Containing 1,2,4‐Triazole Oxime Ether Moiety

Strobilurins are a class of important agricultural fungicides that are used widely in plant protection. To find new strobilurin analogues with high activity against resistant pathogens, a series of new strobilurin derivatives bearing 1,2,4‐triazole oxime ether side chain 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h were designed and synthesized. Their structures were confirmed by IR, ¹H NMR, EIMS, and elemental analyses. Bioassays indicated that some of the compounds showed good fungicidal activities in the concentration of 50 mg/L. For example, compound 3f possessed 100%, 100%, and 95.5% inhibition against Fusarium omysporum, Physalospora piricola Nose, and Gibberella saubinetii at the concentration of 50 mg/L, respectively.     

Design,Synthesis and Molecular Modeling of Nonsteroidal Anti‐inflammatory Drugs Tagged Substituted 1,2,3‐Triazole Derivatives and Evaluation of Their Biological Activities

A novel series of 1,4‐disubstituted‐1,2,3‐triazole derivatives 3a – l and 5a – i were one‐pot synthesized via CuAAC‐alkyne click chemistry and evaluated for their antibacterial activity against four organisms and screened for their anticancer activity against human colon cancer cell line HT‐29 and human lung cancer cell line HTB‐29. These hybrid molecules structure elucidation has been performed by IR, ¹H‐NMR, ¹³C‐NMR, and mass spectral analysis. Synthesized nonsteroidal anti‐inflammatory drugs‐triazoles evaluated for their antibacterial activities against bacterial microorganisms Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Klebsiella pneumonia. Final compounds 3i , 3c , and 5b showed magnificent broad spectrum activity against P. aeruginosa, K. pneumonia, E. coli, and S. aureus with zone of inhibition values of 20, 15, 17, and 16 mm, respectively. Among the series of compound, 3j showed the best antibacterial activity against all the strains. Further, the compounds 3i and 5a were more cytotoxic than cisplatin against all tested two human cancer cell lines, with 50.8%, and 52.3% and 73.4% and 75.3% of growth, respectively. The synthesized compounds were tested for kinase inhibitory activity against glycogen synthase kinase‐3 protein kinases, in addition, for cytotoxic activity against two different human cancer cell lines.     

Design,Synthesis, and Fungicidal Activity of Novel Imidazo[4,5‐b]pyridine Derivatives

A series of novel imidazo[4,5‐b]pyridine derivatives were designed and synthesized. The structures of all the newly synthesized compounds were identified by spectroscopic data NMR, MS, and elemental analysis. Bioassay showed that the compounds exhibited potent fungicidal activities against Erysiphe graminis, Puccinia polysora, and so forth. Particularly, 2‐chloro‐5‐((5‐methoxy‐2‐(2‐(trifluoromethyl)phenyl)‐3H‐imidazo[4,5‐b]pyridin‐3‐yl)methyl)thiazole ( 9b ) displayed fungicidal potency against P. polysora. Its EC₅₀ value: 4.00 mg/L is comparable with that of tebuconazole. The structure–activity relationship for the target compounds is discussed.     

Design,Synthesis, and Biological Screening of Novel Anthranilic Diamides

Three series of new anthranilic diamide derivatives containing sulfide, N‐cyanomethylsulfilimine, and N‐cyanomethylsulfoximine groups were designed and synthesized by combining the active substructures of anthranilic diamides and sulfoxaflor. The structures of all newly synthesized compounds were confirmed by IR and ¹H/¹³C‐NMR, and some of them were confirmed by elemental analysis or HRMS too. The synthesized compounds were screened for their insecticidal and fungicidal activities. Bioasssay results indicated that some of the synthesized compounds possessed certain degrees of insecticidal activity against Mythimna separata. However, some compounds exhibited good fungicidal activity against Sclerotinia sclerotiorum.     

Synthesis and Evaluation of 1,3,4‐Thiadiazole Derivatives Containing Cyclopentylpropionamide as Potential Antibacterial Agent

This study aimed to identify new strategies for the control of these plant bacterial diseases by combining a pharmacophoric group of different bioactive compounds. A series of 3‐cyclopentylpropionamide containing 1,3,4‐thiadiazole derivatives was synthesized and characterized via ¹H‐NMR, ¹³C‐NMR, and HRMS. Bioassay results indicated that compounds 7a , 7d , 7j , 7m , 7n , and 7s had excellent antibacterial activity compared with the positive control. Among them, compound 7a exhibited remarkable inhibitory effect against Xoo with an EC₅₀ of 21.41 μg/mL, which surpassed that of thiodiazole copper (67.71 μg/mL) and bismerthiazol (69.05 μg/mL). Greenhouse condition tests further revealed that 7a had approximately equal curative activity and better protection activity (41.58%) against bacterial leaf blight of rice than that of thiodiazole copper and bismerthiazol (46.86 and 42.25%, respectively). Structure–activity relationship analysis exhibited that sulfone fragment favored inhibition. Overall, this study suggested that derivatives containing 1,3,4‐thiadiazole 3‐cyclopentylpropanamide can be used as new lead compounds for bactericide studies.     

Synthesis and Antimicrobial Evaluation of Novel Derivatives of Semicarbazide and 1,2,4‐triazole

Reaction of phenoxyacetic acid hydrazide with isocyanate was used to the synthesis of new semicarbazide derivatives. Cyclization of these compounds in a 2% aqueous solution of sodium hydroxide led to formation of 1,2,4‐triazole‐3‐one. The chemical structure of synthesized compounds was confirmed by elemental analysis and spectroscopic methods (¹H and ¹³C NMR). On the basis of the NMR, spectra were found that cyclic compounds 1,2,4‐triazole exist in the ‐one form. Moreover, all derivatives were examined for their in vitro activity against some species of bacteria. New compounds presented mild or moderate antimicrobial activity only against reference Gram‐positive bacteria. Two derivatives (one semicarbazide and one triazole) showed bactericidal or bacteriostatic activity.     

Synthesis and Herbicidal Activity of 1,2,4‐Triazole Derivatives Containing a Pyrazole Moiety

A series of triazole derivatives containing a pyrazole moiety were synthesized and characterized by ¹H NMR, ¹³C NMR, and HRMS. The herbicidal activities of these compounds were tested against lettuce and bentgrass. Most of the tested compounds were moderately herbicidal activity against lettuce and bentgrass. Among them, compounds 6f and 6g had the highest herbicidal activity (80% inhibitory) against lettuce and bentgrass.     

Synthesis,Characterization, and Biological Evaluation of Novel 3‐(4‐Chlorophenyl)‐2‐(substituted)quinazolin‐4(3H)‐one Derivatives as Multi‐target Anti‐inflammatory Agents

A novel class of 3‐(4‐chlorophenyl)‐2‐(substituted)quinazolin‐4(3H)‐one derivatives were synthesized, and the structure of synthesized compounds was characterized by IR, ¹H NMR, and mass spectroscopy. The newly synthesized compounds ( 4a–g and 6a–g ) were tested for their in vitro cyclooxygenase (COX) inhibition activity. The compounds have inhibitory profile against both COX‐1 and COX‐2, and some of the compounds are found to be selective against COX‐2. The compound 6g showed distinct inhibitory activity on COXs. The synthesized compounds were evaluated for their potential anti‐inflammatory activity as inhibitors of the proinflammatory cytokines IL‐6. Compounds 4d – g showed the highest level of inhibition among all the tested compounds. Thus, our data suggested that these compounds may represent a new class of potent anti‐inflammatory agents.     

Synthesis and Antifungal Activity of Novel 1,2,4‐Triazole Derivatives Containing 1,2,3‐Thiadiazole Moiety

Starting from carbonic acid diethyl ester, a series of 1,2,4‐triazole derivatives containing 1,2,3‐thiadiazole were synthesized. Reactions were performed by microwave irradiation or ultrasonic irradiation as well as by conventional heating. The structure of title compounds was characterized by ¹H‐NMR, MS, and elemental analyses. The fungicidal activities of these compounds were tested in vivo. Most of title compounds exhibited good antifungal activity against Pseudoperonospora cubensis. Some of title compounds displayed moderate antifungal activities against Fusarium oxysporum, Pseudoperonospora cubensis, Sphaerotheca fuligenea, Corynespora cassiicola, and Xanthomonas axonopodis.     

Synthesis,Characterization, and Molecular Docking Study of Some Novel Imidazole Derivatives as Potential Antifungal Agents

The azole pharmacophore is still regarded as a viable lead structure for the synthesis of more effective antifungal agents. In this study, two novel series of imidazole derivatives containing dithiocarbamate (5a–5g) and (benz)azolethiol (6a–6n) side chains that are structurally related to the famous antifungal azole pharmacophore were synthesized, and the structures of them were characterized by spectral (IR, ¹H NMR, ¹³C NMR, and MS spectra) analyses. The synthesized compounds were screened in vitro antifungal activity against pathogenic strains fungi. Theoretical ADME (absorption, distribution, metabolism, and excretion) predictions were calculated for final compounds. A molecular docking study of the most active compound with target “lanosterol 14α‐demethylase” (CYP51) was performed to unravel the mode of antifungal action. Compound 5e , which features imidazole and 4‐methoxybenzyl piperazine scaffolds, showed the most promising antifungal activity with an MIC₅₀ value of 0.78 μg/mL against C. krusei. Effect of the compound 5e against ergosterol biosynthesis was observed by LC–MS–MS method, which is based on quantification of ergosterol level in C. krusei.     

Synthesis and Fungicidal Activity of (E)‐α‐(Methoxyimino)benzeneacetate Derivatives Containing 1,2,4‐Triazole Schiff Base Side Chain

To find new strobilurin analogs with high activity against resistant pathogens, twelve (E)‐α‐(methoxyimino)benzeneacetate derivatives containing 1,2,4‐triazole Schiff base side chain 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k , 3l were designed and synthesized. Their structures were confirmed by IR, ¹H‐NMR, EIMS, and elemental analyses. Bioassays indicated that most of the target compounds showed moderate to good fungicidal activities against Physalospora piricola Nose and Alternaria solani. For example, compounds 3d , 3e , and 3f possessed 99.5%, 100%, and 95.6% inhibition against Physalospora piricola Nose, whereas compounds 3d , 3f , and 3g exhibited 92%, 91%, and 92% inhibition against Alternaria solani at the concentration of 50 mg/L, respectively.     

Antitubercular Activity and Synergistic Study of Novel Pyrazole Derivatives

A series of 20 novel pyrazole derivatives were designed and prepared, characterized by ¹H‐NMR, mass spectra (ES‐MS), ¹³C‐NMR, and elemental analysis. The synthesized compounds were then evaluated for their growth inhibitory activity against Mycobacterium smegmatis mc² 155 initially. Rifampicin was used as standard reference. In this screening, derivatives 9 , 10 , and 11 presented superior inhibition compared with standard. Later, these three compounds were exposed for their Mycobacterium tuberculosis H37Rv inhibitory assay using rifampicin as standard reference. Encouraging M. smegmatis mc² 155 inhibition (9 μg/mL), M. tuberculosis H37Rv inhibition (1.9 μg/mL), and synergism with the first‐line and second‐line antibiotics made compound 10 as lead and safe antitubercular agent among the series.     

Synthesis,Antimicrobial, and Anticancer Activities of a New Series of Thieno[2,3‐d] Pyrimidine Derivatives

A new series from thieno[2,3‐d] pyrimidine derivatives have been synthesized based on 2‐(ethylmercapto)‐4‐mercapto‐6‐phenyl‐5‐pyrimidine carbonitrile, these compounds used in the synthesis of many pyrimidothienopyrimidine derivatives and triazolo[1″,5″:1″,6″]pyrimido[4′,5′:4,5]thieno[2,3‐d] pyrimidine derivatives. The chemical composition of these compounds was confirmed by ¹H NMR, ¹³C NMR, and MS techniques. Some of the synthesized compounds were screened for their antimicrobial and anticancer agent. Compound ( 9b ) showed strong effect on Aspergillus Fumigatus (RCMB 2568), Candida albicans (RCMB 05036), Saphylococcus aureus (RCMB 010010), Bacillis subtilis (RCMB 010067), Salmonella sp. (RCMB 010043), and Escherichia coli (RCMB 010052). Compounds ( 2 ) and ( 5a – k ) were evaluated for their IC₅₀ values against two cancer cell lines (MCF‐7 and HeLa cells) in the presence of Paclitaxel as reference material. Compound ( 5g ) showed the highest cytotoxicity against MCF‐7 (IC₅₀ values about 18.87 ± 0.2 μg/mL) cells compared with Paclitaxel (IC₅₀ values about 40.37 ± 1.7 μg/mL). Also, compound ( 5d ) showed the highest cytotoxicity against HeLa (IC₅₀ values about 40.74 ± 1.7 μg/mL) cells compared with Paclitaxel (IC₅₀ values about 45.78 ± 0.8 μg/mL).     

Design,synthesis, and pesticidal activities of novel pyrimidin-4-amine derivatives containing trifluoroethyl sulfide moiety

In order to overcome the problem of pesticide resistance, it is necessary to discover novel pesticides with new mechanisms of action. Herein, a series of novel pyrimidin-4-amine derivatives containing trifluoroethyl sulfide moiety were designed and synthesized. Bioassays indicated that the title compounds synthesized possessed excellent acaricidal activity against Tetranychus urticae and fungicidal activity against Erysiphe graminis and Puccinia sorghi. Especially, the acaricidal activity of 5-chloro-6-(difluoromethyl)-N-(2-(2-fluoro-4-methyl-5-((2,2,2-trifluoroethyl)thio)phenoxy)ethyl)pyrimidin-4-amine (compound T4 , LC₅₀ = 0.19 mg/L) against T. urticae was close to commercial acaricide cyenopyrafen, and the fungicidal activity of 5-chloro-6-(difluoromethyl)-2-methyl-N-(2-(3-((2,2,2-trifluoroethyl)thio)phenoxy)ethyl)pyrimidin-4-amine (compound T15 , EC₅₀ = 1.32 mg/L) against P. sorghi. was superior to commercial fungicide tebuconazole. The synthesis and characterization of these compounds were given and the structure–activity relationships were discussed.