Abstract: A process for the preparation of a known pesticidal .alpha.-cyano-3-phenoxy-benzyl 3-alkenyl-2,2-dimethyl-cyclopropanecarboxylate of the general formula ##STR1## in which R.sup.1 and R.sup.2 independently of each other represent a hydrogen or halogen atom,R.sup.3 represents a hydrogen or halogen atom or an optionally substituted alkyl group, andR.sup.4 represents a halogen atom, an optionally substituted alkyl or alkenyl radical or an optionally substituted phenyl group, or, together with R.sup.3, represents an alkanediyl (alkylene) radical,comprises reacting a 3-alkenyl-2,2-dimethyl-cyclopropanecarboxylic acid-chloride of the general formula ##STR2## with a 3-phenoxy-benzaldehyde of the general formula ##STR3## --or an adduct thereof with an alkali metal bisulphite (hydrogen sulphite or pyrosulphite)--and an alkali metal cyanide, using an alkyl ester of a C.sub.1 to C.sub.

Abstract: A process for the preparation of 1-amino-cyclopropane-carboxylic acid or a derivative thereof of the general formula ##STR1## in which R.sup.1 represents hydrogen or alkyl andR.sup.2 represents hydrogen or a radical --CO--R.sup.3, whereinR.sup.3 represents hydrogen, alkyl, aryl or alkoxy, in which a 2-cycloamino-4-methylthio-butanoic acid ester ("acyl-methionine ester") of the general formula ##STR2## in which R.sup.3 has the meaning indicated above andR.sup.4 represents alkyl,is reacted successively with dimethyl sulphate and an alkali metal alcoholate, if appropriate in the presence of a diluent, at a temperature between 80.degree. C. and 150.degree. C., the product is then optionally saponified with aqueous alkali metal hydroxide or alkaline-earth metal hydroxide at a temperature between 70.degree. C. and 150.degree. C., the reaction mixture thereby obtained is acidified with concentrated hydrochloric acid at a temperature between 0.degree. C. and 30.degree. C.

Abstract: A process for the preparation of a 3-bromo-4-fluoro-benzaldehyde acetal of the formula: ##STR1## in which R each independently is a C.sub.1 to C.sub.4 alkyl group or the radicals R together are a C.sub.2 to C.sub.5 alkanediyl radical,comprising reacting 3-bromo-4-fluoro-phenylglyoxylic acid of the formula: ##STR2## with an amine of the formula:H.sub.2 N--R.sup.1in whichR.sup.1 is an alkyl, cycloalkyl or aryl radical, at a temperature between about 0.degree. and 200.degree. C. to produce a 3-bromo-4-fluoro-benzaldimine of the formula: ##STR3## and reacting that with an alcohol or alkanediol of the formula:(HO).sub.n --Rin which n is 1 or 2 in the presence of sulphuric acid at a temperature between about 0.degree. and 100.degree. C. Various of the reactants are new and syntheses are given.

Abstract: Combating ectoparasites with the substantially pure isomer mixture (.+-.)-trans-3-(E/Z-2-Chloro-2-(4-chlorophenyl)-vinyl)-2,2-dimethyl-cyclop ropanecarboxylic acid (.+-.)-(.alpha.-cyano-3-phenoxy-4-fluoro-benzyl) ester or the individual E- and Z-isomers of the formula ##STR1## The intermediate free acids, acid chlorides and esters thereof are also shown.