Abstract: Compounds of formula (I), wherein R1 is hydrogen or chlorine and R2 is hydrogen, C1-C8alkyl, or C1-C8 alkyl substituted by C1-C6alkoxy or by C3-C6alkenyloxy, can be prepared by: a) introducing the major portion of the amount to be reacted of a compound of formula (II) into a solvent mixture comprising at least one organic solvent capable of forming an azeotrope with water, and at least one aprotic-dipolar solvent; b) metering in an aqueous strong base in an amount equivalent to that major portion of the total amount of the compound of formula (II); c) adding the remaining portion of the amount to be reacted of the compound of formula (II); d) adding a weak base in an amount that is at least equivalent to that remaining portion; e) removing the water from the reaction mixture by azeotropic distillation; f) adding a compound of formula (III), wherein R2 is as defined for formula (I); and g) isolating the resulting compound of formula (I) from the reaction mixture.

Abstract: Compounds of formula (I), wherein R1 is hydrogen or chlorine and R2 is hydrogen, C1-C8alkyl, or C1-C8alkyl substituted by C1-C6alkoxy or by C3-C6alkenyloxy, can be prepared by: a) introducing the major portion of the amount to be reacted of a compound of formula (II) into a solvent mixture comprising at least one organic solvent capable of forming an azeotrope with water, and at least one aprotic-dipolar solvent; b) metering in an aqueous strong base in an amount equivalent to that major portion of the total amount of the compound of formula (II); c) adding the remaining portion of the amount to be reacted of the compound of formula (II); d) adding a weak base in an amount that is at least equivalent to that remaining portion; e) removing the water from the reaction mixture by azeotropic distillation; f) adding a compound of formula (III), wherein R2 is as defined for formula (I); and g) isolating the resulting compound of formula (I) from the reaction mixture.

Abstract: Novel substituted 1,3-benzodithiol-2-N,N-dialkyliminium salts of the formula ##STR1## wherein R.sub.1 and R.sub.2 independently of one another are each hydrogen, C.sub.1 -C.sub.5 -alkyl, C.sub.3 -C.sub.6 -cycloalkyl, C.sub.3 -alkenyl, C.sub.3 -C.sub.5 -alkynyl or the radical --(CH.sub.2).sub.n --OR, in which R is C.sub.1 -C.sub.4 -alkyl, and n is the number 2 or 3; R.sub.3 and R.sub.4 independently of one another are each C.sub.1 -C.sub.4 -alkyl, or together they are the radical --(CH.sub.2).sub.4 -- or --(CH.sub.2).sub.5 --; and X.sup..crclbar. is a molar equivalent of an anion of an inorganic or organic acid; processes for producing these compounds, as well as compositions containing them, and their use for combating pests, particularly for combating members of the order Acarina which infest plants and animals. The novel compounds are distinguished by their special effectiveness against mites which damage plants.