N-Isopropyl 2-chloroethyl (thiono)phosphonamides - plant-growth regulators e.g. for reducing vegetative growth of grasses

摘要

(Thiono)phosphonamides of formula (I) are new: (X=O or S; R=acetyl or R1R2PX; X1=O or S; R1=1-4C alkoxy or 2-chloroethyl; R2=1-4C alkoxy or alkylamino or NH2). They are prepd. by reacting corresp. phosphononyl halide with ROY(Y=H, alkali(ne earth) metal or NH4). (I) are plant growth regulators more active than 2-chloroethane phosphonic acid. They inhibit vegetative growth, esp. of grasses (to reduce amt. of mowing of lawns or to reduce lodging in cereals); encourage flower and fruit formation; induce parthenocarpic fruiting and affect the sex of flowers; stimulate prodn. of secondary plant products e.g. nibber latex; prevent growth of side-shoots in tobacco; are defoliants; inhibit premature fruit drop and control fruit ripening; improve resistance to frost and drought and induce non-seasonal germination and growth. They are applied in usual forms at 0.01-50, pref. 0.1-10 kg/hectare.