The cis-and traps-isomers of 1-(4-chlorophenyl)-2-(1 H-1, 2, 4-triazol-l-yl) cycloheptanol (1, 2) were compared in antifungal and plant growth-inhibitory activities. The cis-isomer of triazolylcycloheptanol had stronger antifungal activity against most fungi than the transisomer in vitro. Against Rosellinia nacatrix, however, the traps-isomer showed much stronger antifungal activity than the cis-isomer. In preventive activity against cucumber gray mold, powdery mildew, sclerotinia rot and rice blast, the cis-isomer was much stronger than the traps-isomer. In disease-controlling activity against wheat powdery mildew and oat crown rust, the cis-isomer was slightly stronger than the traps-isomer, whereas against rice sheath blight both isomers were similarly active. On the other hand, the traps-isomer had much stronger inhibitory activity than the cis-isomer on the growth of rice seedlings. Diastereomers of 1-substituted-2-(1 H-1, 2, 4-triazol-l-yl) cyclohexanols (3-8) were also compared in biological activity. In disease-controlling activity the cis-isomers were more effective than the corresponding traps-isomers against cucumber gray mold and powdery mildew. In plant growth inhibitory activity the traps-isomers were more effective than the cis-isomers on rice seedlings. Between the two enantiomers of cis-1-(4-chlorophenyl)-2-(1 H-1, 2, 4-triazol-1-yl)cycloheptanol (1), the preventive activity of the (l)-enantiomer was about two times stronger than that of the (d)-enantiomer against cucumber gray mold and powdery mildew. The (l)-enantiomer also had stronger growth inhibitory activity on rice seedlings than the (d)-enantiomer.

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A number of alkoxyiminophenylacetamide derivatives were synthesized and their fungicidal activities were examined. Studies of structure-activity relationships revealed strongest fungicidal activity when the alkoxyimino moiety and the acetamide moiety were each substituted with a methyl group. When the 2-position of the benzene ring on the phenylacetamide moiety was substituted with a phenoxy or phenoxymethyl group, good fungicidal activity was obtained. Introduction of other substituents on the benzene ring of the phenylacetamide moiety resulted in decrease of the fungicidal activity. However, introduction of some substituents on the benzene ring of the 2-phenoxy group increased the activity to some extent. Between the two oxime geometrical isomers, the activity of the E-form was much stronger than that of the Z-form. Consequently, (E)-2-methoxyimino-N-methyl-2-(2-phenoxyphenyl)acetamide was selected as a candidate fungicide for rice diseases.

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