Structures and pesticidal activities of derivatives of dinitrophenols. VI.—Structure and pre‐emergence herbicidal activity of certain alkyldinitrophenols and their esters

Abstract

The activities of DNOC, dinoseb, dinoterb and dinosam and the 5-methyl analogues (1; R = BUS, But, or CHMePr" and R' = Me) of these phenols against Capsella bursa-pastoris, Chenopodium album, Senecio vulgaris, Stellaria media and Rumex spp., and their effects on peas, oats, beet, cabbage and carrots, were investigated by pre-emergence application to soil. The effects of esterification of these phenols with aliphatic acids, of esterification of dinoterb with dibasic acids, aromatic acids, substituted carbonic acids, and of etherification on activity were investigated. 2-t-Butyl phenols and their aliphatic esters proved more active than the corresponding compounds of the other phenols. Acetylation improved the activity of dinoterb and medinoterb. Halogenation reduced the activity of the acetate of dinoterb, but unsaturation of the ester chain enhanced the activity of dinoterb esters. Esterification of dinoterb with aromatic acids, substituted carbonic acids, oxalic and adipic acids, and etherification led to compounds of low activity. In general, all compounds caused little damage to peas and oats. Dinoterb esters damaged cabbage plants. Esters of medinoterb were generally less damaging to crops than were dinoterb esters.

The Nitroaromatic Group in Drug Design. Pharmacology and Toxicology (for Nonpharmacologists)

“…Recall that one of the requirements of uncoupling agents is an ionizable acidic group. Removal of the acidic hydroxyl by formation of nonionizable derivatives dramatically reduces the herbicidal effectiveness of these compounds (Pianka and Browne, 1967). Interestingly, acetylation enhances the activity (Pianka and Browne, 1967).…”

“…Removal of the acidic hydroxyl by formation of nonionizable derivatives dramatically reduces the herbicidal effectiveness of these compounds (Pianka and Browne, 1967). Interestingly, acetylation enhances the activity (Pianka and Browne, 1967). In this case it is possible that the acetylated derivative is acting as a pro-drug, allowing penetration through a lipoid barrier, followed by hydrolysis back to the parent drug (Scheme VIII).…”