Xinghai Li

Synthesis, fungicidal activity, and structure-activity relationship of 2-oxo- and 2-hydroxycycloalkylsulfonamides.

To explore new potential fungicides, a series of novel compounds, including 11 2-oxocycloalkylsulfonamide (3) and 21 2-hydroxycycloalkylsulfonamide (4) derivatives, were synthesized and their structures were confirmed by (1)H nuclear magnetic resonance (NMR), infrared (IR), and elemental analysis. The results of the bioassay showed that the compounds 3 and 4 possessed excellent fungicidal activity against Botrytis cinerea Pers. both in vitro and in vivo. The fungicidal activity of the compounds with 7- or 8-membered rings is better than those with 5-, 6-, or 12-membered rings. According to the results of the mycelium growth rate test, the EC50 values of the compounds 3C, 4C, 3D, and 4D were 0.80, 0.85, 1.22, and 1.09 μg/mL, respectively, and similar to or better than commercial fungicide procymidone. The bioassay results of spore germination indicated that most of the compounds exhibited obvious inhibitory effects against B. cinerea and the inhibition rates of 2-oxocycloalkylsulfonamides were higher than 2-hydroxycycloalkylsulfonamides, among them. The EC50 values of compounds 3A, 3B17, 3E, and 4A were 4.21, 4.21 3.24, and 5.29 μg/mL, respectively. Those compounds containing 5- or 6-membered rings showed better activity than those containing 7-, 8-, or 12-membered rings. Furthermore, the results of the pot culture test showed that almost all of the compounds had effective control activity in vivo and 2-hydroxycycloalkylsulfonamides were obviously superior to 2-oxocycloalkylsulfonamides. The compounds 3E, 4C and 4D presented higher control efficacy than procymidone and pyrimethanil against gray mold disease on cucumber plants.

Synthesis of 2-amino-6-oxocyclohexenyl- sulfonamides and their activity against Botrytis cinerea

BACKGROUND With the objective of exploring the fungicidal activity of 2-oxocyclohexylsulfonamides (2), a series of novel 2-amino-6-oxocyclohexenylsulfonamides (6 to 23) were synthesised, and their fungicidal activities against Botrytis cinerea Pers. were evaluated in vitro and in vivo. RESULTS The compounds were characterised by IR, 1H NMR and elemental analysis. Bioassay results of mycelial growth showed that compounds 6 to 23 had a moderate antifungal activity against B. cinerea. N-(2-methylphenyl)-2-(2-methylphenylamino)-4,4-dimethyl-6-oxocyclohexenylsulfonamide (13) and N-(2-chlorophenyl)-2-(2-chlorophenylamino)-6-oxocyclohexenylsulfonamide (21) showed best antifungal activities, with EC50 values of 8.05 and 10.56 µg mL(-1) respectively. Commercial fungicide procymidone provided an EC50 value of 0.63 µg mL(-1) . The conidial germination assay showed that most of compounds 6 to 23 possessed excellent inhibition of spore germination and germ-tube elongation of conidia of B. cinerea. For in vivo control of B. cinerea colonising cucumber leaves, the compound N-cyclohexyl-2-(cyclohexylamino)-4,4-dimethyl-6-oxocyclohexenylsulfonamide (19) showed a better control effect than the commercial fungicide procymidone. CONCLUSION The present work demonstrated that 2-amino-6-oxocyclohexenylsulfonamides can be used as possible new lead compounds for further developing novel fungicides against B. cinerea.

Synthesis and Fungicidal Activity of N-(2,4,5-trichlorophenyl)-2-Oxo-and 2-Hydroxycycloalkylsulfonamides

A series of N-(2,4,5-trichlorophenyl)-2-Oxo- and 2-Hydroxycycloalkyl- sulfonamides (series II and III) were designed and synthesized based on the leading compound chesulfamide (code name: CAUWL-2004-L-13). Their struc- tures were confirmed by 1 H NMR, IR and elemental analysis. Compounds II and III showed excellent activities against the Botrytis cinerea both in vitro and in vivo. Mycelia growth and conidial germination assays exhibited that EC50 of compound IId were 0.64 μg mL -1 and 0.34 μg mL -1 respectively. For in vivo control of B. cinerea in cucumber seedlings, compounds IIb and IId showed better control effect than the commercial fungicides procymidone and pyrimethanil. In addition, these new compounds had broader fungicidal spectra than chlorothalonil. The fungicidal activity was affected obviously by the size of cycloalkane. All the compounds with six-, seven-, and eight-membered ring showed high fungi- cidal activities.

Synthesis of 2-Acyloxycyclohexylsulfonamides and Evaluation on Their Fungicidal Activity

Eighteen N-substituted phenyl-2-acyloxycyclohexylsulfonamides (III) were designed and synthesized by the reaction of N-substituted phenyl-2-hydroxyl-cycloalkylsulfonamides (I, R1) with acyl chloride (II, R2) in dichloromethane under the catalysis of TMEDA and molecular sieve. High fungicidal active compound N-(2,4,5-trichlorophenyl)-2-(2-ethoxyacetoxy) cyclohexylsulfonamide (III-18) was screened out. Mycelia growth assay against the Botrytis cinerea exhibited that EC50 and EC80 of compound III-18 were 4.17 and 17.15 μg mL−1 respectively, which was better than the commercial fungicide procymidone (EC50 = 4.46 μg mL−1 and EC80 = 35.02 μg mL−1). For in vivo activity against B. cinerea in living leaf of cucumber, the control effect of compound III-18 was better than the fungicide cyprodinil. In addition, this new compound had broader fungicidal spectra than chlorothalonil.

Synthesis and Bioactivity of 5-Substituted-2-furoyl Diacylhydazide Derivatives with Aliphatic Chain

A series of 5-substituted-2-furoyl diacylhydazide derivatives with aliphatic chain were designed and synthesized. Their structures were characterized by IR, 1H NMR, elemental analysis, and X-ray single crystal diffraction. The anti-tumor bioassay revealed that some title compounds exhibited promising activity against the selected cancer cell lines, especially against the human promyelocytic leukemic cells (HL-60). Their fungicidal tests indicated that most of the title compounds showed significant anti-fungal activity. The preliminary structure-activity relationship showed that the aliphatic chain length and differences in the R2 group had obvious effects on the anti-tumor and anti-fungal activities. The bioassay results demonstrated that the title compounds hold great promise as novel lead compounds for further drug discovery.

Synthesis, Fungicidal Activity and Mode of Action of 4-Phenyl-6-trifluoromethyl-2-aminopyrimidines against Botrytis cinerea.

Anilinopyrimidines are the main chemical agents for management of Botrytis cinerea. However, the drug resistance in fungi against this kind of compounds is very serious. To explore new potential fungicides against B. cinerea, a series of 4-phenyl-6-trifluoromethyl-2-amino-pyrimidine compounds (compounds III-1 to III-22) were synthesized, and their structures were confirmed by 1H-NMR, IR and MS. Most of these compounds possessed excellent fungicidal activity. The compounds III-3 and III-13 showed higher fungicidal activity than the positive control pyrimethanil on fructose gelatin agar (FGA), and compound III-3 on potato dextrose agar (PDA) indicated high activity compared to the positive control cyprodinil. In vivo greenhouse results indicated that the activity of compounds III-3, III-8, and III-11 was significantly higher than that of the fungicide pyrimethanil. Scanning electron micrography (SEM) and transmission electron micrography (TEM) were applied to illustrate the mechanism of title compounds against B. cinerea. The title compounds, especially those containing a fluorine atom at the ortho-position on the benzene ring, could maintain the antifungal activity against B. cinerea, but their mechanism of action is different from that of cyprodinil. The present study lays a good foundation for us to find more efficient reagents against B. cinerea.

Design, Synthesis and Fungicidal Activity of 2-Substituted Phenyl-2-oxo-, 2-Hydroxy- and 2-Acyloxyethylsulfonamides

Sulfonyl-containing compounds, which exhibit a broad spectrum of biological activities, comprise a substantial proportion of and play a vital role, not only in medicines but also in agrochemicals. As a result increasing attention has been paid to the research and development of sulfonyl derivatives. A series of thirty-eight 2-substituted phenyl-2-oxo- III, 2-hydroxy- IV and 2-acyloxyethylsulfonamides V were obtained and their structures confirmed by IR, 1H-NMR, and elemental analysis. The in vitro and in vivo bioactivities against two Botrytis cinerea strains, DL-11 and HLD-15, which differ in their sensitivity to procymidone, were evaluated. The in vitro activity results showed that the EC50 values of compounds V-1 and V-9 were 0.10, 0.01 mg L−1 against the sensitive strain DL-11 and 3.32, 7.72 mg L−1 against the resistant strain HLD-15, respectively. For in vivo activity against B. cinerea, compound V-13 and V-14 showed better control effect than the commercial fungicides procymidone and pyrimethanil. The further in vitro bioassay showed that compounds III, IV and V had broad fungicidal spectra against different phytopathogenic fungi. Most of the title compounds showed high fungicidal activities, which could be used as lead compounds for further developing novel fungicidal compounds against Botrytis cinerea.

Design, synthesis and fungicidal activity of novel 2-substituted aminocycloalkylsulfonamides.

A series of novel 2-substituted aminocycloalkylsulfonamides were designed and synthesized by highly selective N-alkylation reaction, whose structures were characterized by 1H NMR, 13C NMR and HRMS. Among them, the configuration of compounds III12 and III20 were confirmed by X-ray single crystal diffraction. Bioassays demonstrated that the title compounds had considerable effects on different strains of Botrytis cinerea and Pyricularia grisea. Comparing with positive control procymidone (EC50=10.31mg/L), compounds III28, III29, III30 and III31 showed excellent fungicidal activity against a strain of B. cinerea (CY-09), with EC50 values of 3.17, 3.04, 2.54 and 1.99mg/L respectively. Their in vivo fungicidal activities were also better than the positive controls cyprodinil, procymidone, boscalid and carbendazim in pot experiments. Moreover, the fungicidal activity of III28 (EC50=4.62mg/L) against P. grisea was also better than that of the positive control isoprothiolane (EC50=6.11mg/L). Compound III28 would be great promise as a hit compound for further study based on the structure-activity relationship.

Synthesis, Fungicidal Activity, and Structure Activity Relationship of β -Acylaminocycloalkylsulfonamides against Botrytis cinerea

In order to discover new antifungal agrochemicals that could have highly active and novel motifs, thirty-six new 2-acylaminocycloalkylsulfonamides (IV) were synthesized. Their structures were characterized and confirmed by 1H NMR, 13C NMR, IR, MS, elemental analysis and X-ray single crystal diffraction. In vitro and in vivo activities against various Botrytis cinerea strains were evaluated. Bioassay results revealed that most of the title compounds exhibited excellent in vitro fungicidal activity, in which compound IV-26 showed the highest activity against sensitive, low-resistant, moderate-resistant and high-resistant strains of B. cinerea compared with the positive fungicide procymidone. Meanwhile in vivo fungicidal activity of compound IV-31 was better than the commercial fungicides procymidone and chesulfamide in greenhouse trial. The structure activity relationship (SAR) was also discussed and the results were of importance to the structural optimization and development of more potent sulfonamides antifungal agents.

Design, Synthesis, and SAR of Novel 2-Glycinamide Cyclohexyl Sulfonamide Derivatives against Botrytis cinerea

N-(2-trifluoromethyl-4-chlorophenyl)-2-oxocyclohexyl sulfonamide (chesulfamide) is in the limelight as a novel fungicide, and has fungicidal activity against Botrytis cinerea. For exploring more novel structures, 33 new compounds were synthesized by N-alkylation and acid–amine coupling reactions with chesulfamide as the core moiety, and their structures were characterized and established by 1H-NMR, 13C-NMR, MS, and elemental analysis. The structure of (1R,2S)-2-(2-(N-(4-chloro-2-trifluoromethylphenyl)sulfamoyl)-cyclohexylamino)-N-(2-trifluoromethylphenyl) acetamide (II-19) was defined by X-ray single crystal diffraction. The in vivo and in vitro fungicidal activities against B. cinerea were evaluated. The bioassay results of mycelial growth demonstrated that most compounds exhibited excellent inhibitory activity against B. cinerea at 50 μg mL−1, and 7 compounds showed lower EC50 values than boscalid (EC50 = 4.46 μg mL−1) against B. cinerea (CY-09). In cucumber pot experiment, the inhibitory rates of four compounds (II-4, II-5, II-12, and II-13) against B. cinerea were 90.48, 93.45, 92.86, and 91.07, which were better than cyprodinil (88.69%), the best performing of all controls. In tomato pot experiment, the control efficacy of two analogs (II-8 and II-15) were 87.98 and 87.97% at 200 μg mL−1, which were significantly higher than boscalid (78.10%). Most compounds have an excellent fungicidal effect on B. cinerea, with potential as a lead compound for developing new pesticides.