Synthesis and Fungicidal Activity of Novel Pyrazole-4-carbox-amide Compounds Containing Tertiary Alcohol Moiety

Abstract

A series of novel pyrazole-4-carboxamide compounds were designed and synthesized through introducing a tertiary alcohol moiety into the C-3 position of the pyrazole ring based on the chracteristics of pyrazole-4-carboxamide fungicides and natural products with a tertiary alcohol moiety. Their structures were characterized by 1 H NMR, 13 C NMR, HR-ESI-MS data and X-ray diffraction. The preliminary bioassay results indicated that some of these compounds exhibit certain fungicidal activities against tested phytopathogens at the concentration of 100 µg/mL. N-(2-Fluorophenyl)-3-(1-hydroxycyclohexyl)-1,5dimethyl-1H-pyrazole-4-carboxamide (B 1) and N-(thiazol-2-yl)-3-(1-hydroxycyclohexyl)-1,5-dimethyl-1H-pyrazole-4-carboxamide (B 10) have EC 50 values of 76.3 and 71.9 µg/mL against Pythium aphanidermatum. B 10 has an EC 50 value of 85.4 µg/mL against Phytophthora capsici, respectively.

Synthesis and Antifungal Activity of 3-Aryl-7-methyl- 7-hydroxy-2-octen-6-olide

“…Compounds R-5k and S-5k from chiral diol esters 18a and 18b via chiral diol acids 22a and 22b in 86% and 91% yields with ee values of 95.0% and 97.7%, compounds R-5n and S-5n from chiral diol esters 19a and 19b via chiral diol acids 23a and 23b in 69% and 72% yields with ee values of 98.1% and 95.2% were prepared in a similar approach, respectively. The in vitro antifungal activities of synthesized sevenmembered lactone were evaluated using the mycelial growth rate test at (25±0.5) ℃ following the protocol in reference, [33,[37][38][39] Chlorothalonil and carbendazim used as positive control, and the EC 50 values were determined from the inhibition rates of five different concentrations for the compounds having more than 70% inhibition rates, which were given in Table 2. The data showed that most of the synthesized seven-membered lactones have significant antifungal activities against these phytopathogens with EC 50 values of 0.6～150.8 µg/mL.…”

“…The fungicidal activities of compounds 5a～5s against R. Solani, A. Solani, F. graminearum, S. Sclerotiorum, B. cinerea and P. capsici were evaluated using methods in the references [33,[37][38][39] by the mycelium growth rate.…”

Synthesis and Unexpected Insecticidal Activity of (E)-3-(1-Imino-ethyl)-5,5-disubstituted-4-(methylamino)furan-2(5H)-one

“…In the development courses of novel pesticides, several kinds of compounds were designed and synthesized based on the spirocyclic butenolide moiety using the strategy of diversity-oriented synthesis, [1][2][3] and most of compounds from our constructed molecular library (Scheme 1) were found to exhibit excellent fungicidal and insecticidal activ-ities against several phytopathogens and harmful insects in our laboratory. [4][5][6][7][8][9][10][11][12] These results showed that our compounds derived from the spirocyclic butenolide moiety by diversity-oriented synthesis strategy exhibit the wide-range bioactivities in both fungicide and insecticide.…”

Synthesis and Antifungal Activity of 3,7-Dimethyl-7-hydroxy-2-octen-6-olide Analogues

“…The antifungal activities of synthesized seven-membered lactone were evaluated using the mycelial growth rate test at (25±0.5) ℃ following the protocol in reference, [48][49][50] chlorothalonil and carbendazim used as positive control, and EC 50 values were determined from the inhibition rates of five different concentrations for the compounds having more than 70% inhibition rates, which were given in Table 2. The data showed that most of the synthesized seven-membered lactones have significant antifungal activities against these phytopathgens, especially against R. solani and A. solani with EC 50 values of 2.8～134.2 µg/mL.…”

“…The fungicidal activities of compounds 1～14 against R. Solani, A. Solani, F. graminearum, S. Sclerotiorum, B. cinerea and P. capsici were evaluated using methods in the references [48][49][50] by mycelium growth rate. Procedure for inhibition rate: The stock 2000 mg/L DMSO solution of tested compounds was prepared in advance.…”