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Structures and pesticidal activities of derivatives of dinitrophenols. IX. —Effects of substitution of dinitrophenols with C 4 to C 13 α‐branched alkyl groups and of esterification on the eradication of apple mildew
Author(s) -
Pianka M.,
Sweet P. J. J.
Publication year - 1968
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740191112
Subject(s) - chemistry , alkyl , isopropyl , dinitrophenol , phenols , medicinal chemistry , organic chemistry , stereochemistry , biochemistry
The eradication of apple mildew caused by Podosphaera leucotricha (Ell. and Everh.) Salm. with 2‐(C 4 to C 13 α‐branched alkyl)‐4,6‐dinitrophenols and 4‐(C 4 to C 13 α‐branched alkyl)‐2,6‐dinitrophenols was examined. 4‐(1‐Ethylbutyl)‐ and most 4‐(C 7 to C 12 α‐branched alkyl)‐2,6‐dinitrophenols were significantly more active than their 2‐alkyl‐4,6‐dinitrophenol analogues. Compounds containing 4‐C 13 alkyls did not show significant activity. Activity generally increased as the α‐alkyl branch lengthened. Methyl carbonates did not show lower activity than the parent phenols, but esterification of 4‐(C 12 or C 13 α‐branched alkyl)‐2,6‐dinitrophenols to ethyl carbonates or crotonates gave compounds with reduced activity. Methyl‐, ethyl‐ or isopropyl‐carbonates and crotonates of 4‐(1‐ethylhexyl)‐2,6‐dinitrophenol had much higher activity than the corresponding esters of the 4‐(1‐methylheptyl) isomer or of 2‐(1‐ethyl‐hexyl)‐4,6‐dinitrophenol. Compounds containing long ester chains (C 7 or C 8 ) had less activity than 4‐(1‐ethylhexyl)‐2,6‐dinitrophenol. O ‐Methylation produced compounds with less activity than the parent 4‐(1‐ethylhexyl)‐ and 4‐(1‐propyl‐pentyl)‐2,6‐dinitrophenols.