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

Quantitative Structure-activity Relationships of Antifungal 1-(3,5-Dichlorophenyl)-2,5-pyrrolidinediones and 3-(3,5-Dichlorophenyl)-2,4-oxazolidinediones

“…1 "-'3) The effect of benzene ring substituents on the antifungal activity of I-phenyl-2,5-pyrrolidinediones and N-phenyl-l,2-dimethylcyclopropanedicarboximides against B. cinerea was analyzed in a previous paper. 4 ) The conclusion drawn from this analysis is as follows. The hydrophobic effect is significant only for m-substituents.…”

“…The Iso value (the molar concentration for 50% inhibition of mycelial growth) against B. cinerea was determined by the agar medium dilution method, using the technique identical to that used· in the previous paper. 4 ) Cultivation was performed for 3 days at 24 ±1°C. The activity, expressed as pI so (= log 1/1 50 ), is listed in Tables I and II. ring closure, according to the procedure given by Finkbeiner.…”

“…22 ,23) Hansch and Leo also categorized them as nonhydrogen-bonding substituents. shows that the activity becomes greater with the increasing hydrophobicity of the substituents on the imido ring, independ- (4) ent of the electronic and steric effects. Equation 2 shows also that the hydrophobic substituent effect is not modified by the hydrogen-bonding character of the substituents, whereas .the substituent effect on the activity variations in I-phenyl-2,5-pyrrolidinediones having various benzene ring substituents is modified when the substituents are hydrogen bond acceptors.…”

“…Equation 2 shows also that the hydrophobic substituent effect is not modified by the hydrogen-bonding character of the substituents, whereas .the substituent effect on the activity variations in I-phenyl-2,5-pyrrolidinediones having various benzene ring substituents is modified when the substituents are hydrogen bond acceptors. 4 ) We assumed that both the critical site and mode of action did not differ between 1-(3,5-dichlorophenyl)-2,5-pyrrolidinediones and 3-(3,5 -dichloropheny1)-2, 4-oxazolidinediones; and that the substituents on the pyrrolidine ring exert their effects on the activity in the same way as those on the oxazolidine ring. Thus, the calculation was performed putting the pyrrolidinediones in Table I and the oxazolidinediones in Table II The log P term and intercept in eq.4 are justified above 99.5·% level.…”

“…The partition coefficients (P) were determined with the l-octanol-water system at 24°C for 3-phenyl-2,4-oxazolidinedione and n-propyl sulfone, according to a procedure similar to that previously reported. 4 ) The concentration of 3-phenyl-2,4-oxazolidinedione in the water layer was measured spectrophotometrically, and that of n-propylsulfone in the octanollayer was measured by gas chromatography (support: Chromosorb W, liquid phase: 2% QF-l). The concentration in the other layer was obtained by calculating the difference.…”