GR75726

Novel phosphorous esters of cyanohydrins which exhibit outstanding pesticidal activity. A method of controlling pests by subjecting the pests to a pesticidally active amount of a compound of this invention is also covered. The esters have the general formula: wherein X is O or S; R and R1 are the same or different and are independently hydrogen, lower alkyl (C1-C15), whereby C3-C15 can be branched or unbranched, and wherein the alkyl chain can be substituted or unsubstituted with alkylthio, alkoxy, or one or more halo; cycloalkyl (C3-C8), alkenyl, phenyl, benzyl, pyridinyl, pyrimidinyl, furanyl, pyranyl, naphthalene, thiophene, all of which may be optionally substituted with one or more halogen, nitro, cyano, allyloxy, trihalomethyl, alkyl, alkylthio, alkoxy, or aryloxy, aryloxy alkyl, which can be further substituted with alkoxy, halogen, alkyl, or trihalomethyl groups; taken together R and R1 may form a 5 or 6 membered carbocyclic ring. R2 and R3 can be the same or different and are independently: a) alkyl (C1-C10), b) alkylthio (C1-C8), c) haloalkyl (C1-C8), d) alkoxy (C1-C8) with the proviso that R2 and R3 may not be alkoxy at the same time, e) alkyl or dialkyl amino (C1-C8), f) phenyl or benzyl which can be optionally substituted with one or more nitro, cyano, halogen, trihalomethyl, alkyl, alkoxy alkylthio or aryloxy, g) thioaromatic radicals, and h) oxyaromatic radicals. i