Synthesis of Stereoisomers of Ipconazole and Their Fungicidal and Plant Growth Inhibitory Activities

Abstract

Two racemic diastereomers 5a and 5b, both of which are active ingredient of a seed treatment fungicide on rice, Ipconazole, (1RS, 2SR, 5RS; 1RS, 2SR, 5SR)-2-(4-chloropenzyl)-5-isopropyl-l-(1H-1, 2, 4-triazol-l-ylmethyl)cyclopentanol, and two other racemic diastereomers (1RS, 2RS, 5RS)-5c and (1RS, 2RS, 5SR)-5d were synthesized, and fungicidal activity and plant growth inhibitory activity were examined. Enantiomers of 5a and 5b were prepared, and their fungicidal activities were also examined. Racemic diastereomers 5a, 5b and 5d were more active than 5c in fungicidal activity (EC5o value) in vitro on Gibberella fujikuroi, Cochliobolus miyabeanus and Pyricularia oryzae. In plant growth inhibitory activity test for seed treatment on rice, only 5d was slightly active in the first sheath growth inhibition. The comparative test of enantiomers in vitro revealed that the fungicidal activities of (-)-5a and (-)-5b were higher than those of corresponding (+)-5a and (+)-5b, respectively.

Fungicides, Agricultural, 2. Individual Fungicides

“…Wettable powders, waterdispersible granules, emulsifiable concentrates. Ipconazole can be prepared by reaction of methyl 3-isopropyl-2-oxocyclopentanecarboxylate with 4-chlorobenzyl chloride affording 2-(4-chlorobenzyl)-5-isopropylcyclopentane, which is treated with trimethylsulfoxonium iodide to yield 4-(4-chlorobenzyl)-7-isopropyl-1-oxaspiro [2,4]heptane, which is treated with 1,2,4-triazole in the presence of sodium hydride [128].…”

Structure-Activity Relationships of Enantiomers of the Azole Fungicide Ipconazole and Its Related Compounds

“…1) contain three asymmetric carbons, and as a consequence, there are four possible racemic diastereomers and eight enantiomers. 13) There are cis and trans isomers with respect to the hydroxy group and the benzyl group, and each isomer has further cis and trans isomers with respect to the hydroxy group and the alkyl substituent on the cyclopentane ring. Furthermore, each racemic diastereomer consists of two enantiomers.…”