Structures and pesticidal activities of derivatives of dinitrophenols. XII.—In vitro activity of C3 to C13 α‐branched alkyldinitro‐phenols and their esters and ethers against the spores of Venturia inaequalis and other fungi

The activity in vitro of 2‐(C3 to C13 α‐branched alkyl)‐4,6‐dinitrophenols and 4‐(C4 to C13 α‐branched alkyl)‐2,6‐dinitrophenols and of their various esters and ethers was determined against the spores of Venturia inaequalis (Cooke) Wint., Botrytis cinerea Pers., Fusarium bulbigenum, Cooke & Massee, var. lycopersici (Brushi) Wollenw. and Cercospora melonis Cooke. Several alkyldinitrophenols were highly active against Venturia and the 2‐alkylphenols were generally more active than the 4‐alkylphenols. The alkyldinitrophenols were not effective against the spores of Botrytis, Fusarium and Cercospora.. Esterification of several lower alkyldinitrophenols to methyl carbonates gave compounds with enhanced activity, but methyl carbonates of C7 to C11 alkyl dinitrophenols showed considerably reduced activity. Esterification to ethyl‐ or other alkyl‐carbonates gave compounds with considerably reduced activity against Venturia. Esterification of 2‐isopropyl‐ and 2‐t‐butyl‐4,6‐dinitrophenols to crotonates gave compounds with enhanced activity against Venturia, but crotonates of other phenols showed reduced activity. The acrylates of several C6 to C8 alkyl dinitrophenols proved highly active. Ethers of active phenols showed considerably reduced activity.