PREPARATION OF 2-ETHYL-4-(4-PHENOXYPHENOXYMETHYL)-1,3-DIOXOLANE AND 3-(4-PHENOXYPHENOXY)PROPAN-1,2-DIOL; USE OF THE KETAL AS A PESTICIDE

摘要

The invention relates to a process for the manufacture of a compound of the formula CHEM in which either R1 is hydrogen and R2 is hydrogen or O-R1 and O-R2 taken together are the group of the formula CHEM a compound of the formula I containing the group of the formula II, that is to say a 2-ethyl-4-(4-phenoxyphenoxymethyl)-1,3-dioxolane of the formula CHEM being a mixture of the four configurational isomers, that is to say of the 2R,4S-isomer IIIa, the 2S,4R-isomer IIIb, the 2R,4R-isomer IIIc and the 2S,4S-isomer IIId, in which isomer mixture the racemate of the compounds IIIa and IIIb is present in an amount of from 65 to 90% by weight, relative to the total weight of this isomer mixture, the remainder of this isomer mixture being the racemate of the compounds IIIc and IIId, which process is characterised in that a) for the manufacture of a compound of the formula I, in which R1 is hydrogen and R2 is hydrogen, that is to say of a compound of the formula CHEM the compound of the formula CHEM is reacted with a compound of the formula Y-CH2-CH(OH)-CH2-OH (VI), in which Y is a leaving group, or b) for the manufacture of a compound of the formula III a compound of the formula IV is reacted with the compound of the formula H3C-CH2-C(=O)-H (VII) in the presence of an acid catalyst and without complete removal of the water formed during the reaction, the molar ratio, in which the two reactants are used, being defined as the quotient "number of moles used of the compound of the formula IV : number of moles used of the compound of the formula VII", being 1 or less than 1, or c) for the manufacture of a compound of the formula III the compound of the formula V is reacted with a compound of the formula VI, in which Y is a leaving group, to give a compound of the formula IV, and this compound of the formula IV, without being isolated, is reacted with the compound of the formula VII in the presence of an acid catalyst and without complete removal of the water formed during the reaction, the molar ratio, in which the two reactants are used, being 1 or less than 1, and to a compound of the formula III and its use as active ingredient in the field of pest control.