Synthesis, Fungicidal Activity, and Structure Activity Relationship of ß-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.

Synthesis of 2-amino-6-oxocyclohexenylsulfonamides 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, 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.

[Cloning of alpha-tubulin gene from Fusarium graminearum and analyzing its relationship with carbendazim-resistance].

The full-length nucleotide sequence of alpha-tubulin gene from each of 6 Fusarium graminearum strains from China which had different carbendazim (MBC) sensitivity phenotypes were separated using PCR with 4 primer sets designed in accordance with nucleotide sequence of the gene from the reference isolate, NRRL 31084 (PH-1). The DNA sequence comparison showed that there was no difference in the nucleotide sequence of alpha-tubulin gene amongst 3 sensitive and 3 resistant strains from China. This result demonstrates that there is no relationship between MBC-resistance and alpha-tubulin gene. The full-length of the gene spans 1718 bp, including 6 introns, encoding 449 amino acids. With 99% homology, there is 5 nucleotide differences in alpha-tubulin gene between PH-1 isolate and the 6 strains from China. The homology of the deduced amino acid sequence of the gene is 99.78% between the 6 strains and PH-1 isolate, and 37%-86% between the 6 strains and other 6 species of fungi.