Akira Fujinami

Studies on Biological Activity of Cyclic Imide Compounds:Part I. Antimicrobial Activity of 3-Phenyloxazolidine-2, 4-diones and Related Compounds

The structure-activity relationships of l-phenylpyrrolidine-2,5-dione derivatives were investigated on Sclerotinia sclerotiorum by the agar dilution method. In addition, several representative compounds were tested for antimicrobial spectra in vitro with 15 pathogenic microbes and for foliage protection activity in green house tests with rice blast, rice brown spot, rice sheath blight and kidney bean stem rot. It was found that 3,5-dihalo-substituents on the benzene moiety are essential to high antifungal activity against Sclerotinia sclerotiorum. Generally, l-(3′,5′-dihalophenyl)pyrrolidine-2,5-diones are active against Corticiaceae, Dematiaceae, Pleosporaceae and Sclerotiniaceae, especially active against Sclerotinia sclerotiorum and Botrytis cinerea (the conidia form of Sclerotinia fuckeliana). N-(3,5-Dichlorophenyl)itaconimide showed a peculiarly broad antimicrobial spectrum. In green house tests, these compounds showed high activity against rice brown spot, rice sheath blight and kidney bean stem rot...

Quantitative structure-activity relationships of antifungal N-phenylsuccinimides and N-phenyl-1,2-dimethylcyclopropanedicarboximides☆

Abstract The antifungal activity of 61 N -phenylsuccinimides and 16 N -phenyl-1,2-dimethylcyclopropanedicarboximides having various benzene ring substituents was determined against Botrytis cinerea by the agar medium dilution method. The structure-activity relationships were analyzed using such physicochemical substituent parameters as hydrophobic π, electronic σ 0 , steric E 8 , and HB (hydrogen bonding) values with the multiple regression technique. The π values were derived from log P (octanol-water partition coefficient) values for the N -monosubstituted-phenylsuccinimide system. The hydrophobic effect is significant only for m -substitutents. The stronger the electron withdrawal and the smaller the steric dimensions of the ring substituents, the greater is the activity. When substituents are hydrogen bond acceptors, the effect is to lower the activity. These features are almost identical between two series of compounds.

Structure-activity study of herbicidal N-chloroacetyl-N-phenylglycine esters

Abstract N -Chloroacetyl- N -phenylglycine esters were shown to exert various degrees of growth inhibiting activity against young shoots of annual grasses. The activity against the rice plant and barnyard-grass was determined for 58 derivatives where either the aromatic substituent or ester moiety was modified. The structure-activity relationships were analyzed using physicochemical parameters of the molecule such as log P , σ, and E s , and regression analysis. By comparing the correlations derived for the rice plant and barnyard-grass, the selectivity in herbicidal activity is discussed.

Studies on the Mode of Action of Organophosphorus Compounds:Part II. Inhibition of Mammalian Cholinesterase in vivo Following the Administration of Sumithion and Methylparathion

It was presumed in the previous paper that sumithion was easily absorbed from the gastrointestestinal tract, similarly to methylparathion, following the oral administration to mammals. Inhibition of blood and brain cholinesterase of Guinea pigs and white rats in vivo after oral treatment with sumithion and methylparathion was determined. Inhibition of the enzymes was found to proceed rather rapidly and in most cases it reached maximum within one hour. Sumithion hindered the brain cholinesterase activity far less effectively than methylparathion. Intravenous administration of these phosphorothioates and their oxygen analogs clarified that the latters were more inhibitory on the cholinesterases and that of the two oxygen analogs, sumioxon was less effective. The poor susceptibility of the brain enzyme to sumithion was also observed in this case. This paper deals with the experimental results and their possible implications in the toxicity of the organophosphorus compounds toward mammals.

Quantitative structure-activity relationships for antifungal 3-(3,5-dichlorophenyl)-2,4-imidazolidinediones

The antifungal activity of 441-acyl derivatives of 3-(3,5-dichlorophenyl)-2,4-imidazol- idinedione against Botrytis cinerea, and of 10 1-sulfonyl compounds against Aiternaria kikuchi- ana were assayed by the agar medium dilution method. The structure-activity relationships for the substituents of the acyl and sulfonyl moieties were analyzed with such physicochemical parameters as hydrophobic π, inductive electronic σ1, and steric E′cs and B1 values by multiple regression. The activity of the acyl derivatives against B. cinerea was related parabolically to the hydrophobicity of the substituents. The stronger the electron-donating power, the larger the overall steric bulkiness, and the smaller the minimum width in the direction perpendicular to the bond axis of the substituents, the greater was the activity. The activity of the sulfonyl derivatives against A. kikuciana was related only to the hydrophobicity of the substituents.