Abstract: A bissilylated 1-hydroxycyclopropanecarboxylic acid of the formula ##STR1## in which R.sup.1, R.sup.2, R.sup.3 and R.sup.4 each independently is a hydrogen atom or an alkyl radical, and additionally R.sup.2 and R.sup.3 can together form a 3- to 5-membered carbon bridge, andR.sup.5, R.sup.6 and R.sup.7 each independently is an alkyl radical, is produced by oxidizing with oxygen a cyclobutene-1,2-diol-bis-trialkyl-silyl ether of the formula ##STR2## The products, without isolation, may directly be hydrolyzed to remove the silyl radicals and form known intermediates for further reaction.

Abstract: Styryl-cyclopropane derivatives of the formula ##STR1## in which R.sup.9 represents independently of one another when n=2, halogen, cyano, nitro, or an optionally halogen-substituted alkyl, alkoxy, alkylthio or alkylenedioxy radical,n represents zero, 1, 2, 3, 4 or 5,R.sup.10 represents hydrogen or halogenandY represents acetyl, cyano or carbamoyl, are produced by reacting a benzylphosphonic acid ester of the formula ##STR2## in which R.sup.4 each independently represents alkyl or phenyl or together represent alkylene, with a formylcyclopropane derivative of the formula ##STR3## or by reacting an .alpha.-hydroxyphosphonic acid ester of the formula ##STR4## with an olefinating agent of the formula ##STR5## in which Z' represents a phosphorus-containing radical ##STR6## wherein R.sup.5 and R.sup.6 are identical or different and individually represent alkyl, phenyl, alkoxy or pehnoxy or R.sup.5 and R.sup.6 together represent alkanedioxy,R.sup.

Abstract: A process for the preparation of a 1,1-dichloroalkene of the formula ##STR1## in which R.sup.1 is hydrogen, or an optionally substituted alkyl, alkenyl, alkinyl, cycloalkyl, aralkyl, aralkenyl or aryl radical, andR.sup.2 is an optionally substituted alkyl, alkenyl, alkinyl, cycloalkyl, aralkyl, aralkenyl or aryl radical, orR.sup.1 and R.sup.2 together form an optionally branched and/or optionally benzo-fused hydrocarbon chain,comprising reacting a carbonyl compound of the formula ##STR2## with a trichloromethanephosphonic acid ester of the formula ##STR3## in which R.sup.3 each individually is an alkyl or phenyl radical, or the two radicals R.sup.3 together are alkanediyl,in the presence of at least an equimolar amount of a phosphorous acid triamide of the formulaP(NR.sup.4.sub.2).sub.3in whichR.sup.4 each independently is an alkyl radical, or the two radicals R.sup.4 together are alkanediyl.Advantageously,R.sup.1 is hydrogen,R.sup.2 a C.sub.2 to C.sub.

Abstract: A process for the preparation of a substituted (cyclo) alkanecarboxylic acid .alpha.-cyano-3-phenoxy-benzyl ester of the formula ##STR1## in which R is alkyl or cycloalkyl optionally substituted by halogen, alkyl, cycloalkyl, alkenyl (which is optionally substituted by halogen and/or alkoxy), styryl (which is optionally substituted by halogen, and/or optionally halogen-substituted alkyl, alkoxy, alkylenedioxy and alkylthio radicals), spirocyclically linked, optionally halogen-substituted cycloalk(en)yl (which is optionally benzo-fused) or optionally substituted phenyl andR.sup.5 and R.sup.6 each independently is hydrogen or halogen, comprising adding an aqueous solution or suspension of at least an equimolar amount of a water-soluble cyanide to a mixture of an alkanecarboxylic acid chloride of the formulaR--CO--Cland a 3-phenoxy-benzaldehyde of the formula ##STR2## in a hydrocarbon solvent which is virtually immiscible with water at a temperature between about 0.degree. and 80.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: A process for the preparation of a 1,1-dichloroalkene of the formula ##STR1## in which R.sup.1 is hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, aralkyl or aryl radical, andR.sup.2 is an optionally substituted alkyl, alkenyl, alkynyl, aralkyl, aralkenyl or aryl radical, or cycloalkyl which is optionally substituted by halogen, alkyl, alkanoyl, carbamoyl, cyano or phenyl, orR.sup.1 and R.sup.2 together form a hydrocarbon chain which is optionally branched and/or optionally contains a fused benzene ring,comprising reacting an aldehyde or ketone of the formula ##STR2## with a dichloromethane-phosphonic acid ester of the formula ##STR3## in which R.sup.3 each independently is alkyl or phenyl or the two radicals R.sup.3 together are alkanediyl,in the presence of a base at a temperature between about -50.degree. and +50.degree. C.

Abstract: A process for the preparation of a 2-cyano-3,3-dimethyl-cyclopropane-1-carboxylic acid ester of the formula ##STR1## in which R is optionally substituted alkyl,comprising reacting a 3-halogeno-3-cyano-2,2-dimethyl-propane-1-carboxylic acid ester of the formula ##STR2## in which X is halogen,with a base at a temperature from about 0 to 100.degree. C. The starting esters are new and may be prepared by halogenating a compound of the formula ##STR3## and decarboxylating.

Abstract: In the preparation of a 1,3-dibromo-2,2-dimethyl-propane-1,3-dicarboxylic acid derivative of the formula ##STR1## in which R.sup.1 and R.sup.2 each independently is chlorine or alkoxy, by reacting a 2,2-dimethyl-propane-1,3-dicarboxylic acid derivative of the formula ##STR2## in which R.sup.3 is hydroxy or alkoxy andR.sup.4 is hydroxy, orR.sup.3 and R.sup.4 together are an anhydride oxygen atom,with an acid halide, then reacting the product with bromine at a temperature between 0.degree. and 150.degree. C. to form a 1,3-dibromo-2,2-dimethyl-propane-1,3-dicarboxylic acid chloride and optionally reacting such acid chloride with an alkanol, the improvement which comprises employing an acid chloride as the acid halide, e.g. phosphorus pentachloride, phosphorus oxychloride, phosphorus trichloride, thionyl chloride or phosgene. Compounds of the formula ##STR3## are new. The products are intermediates for making insecticides.

Abstract: A process for the preparation of 4-fluoro-3-phenoxytoluene of the formula ##STR1## comprising reacting 3-bromo-4-fluoro-toluene of the formula ##STR2## with an alkali metal or alkaline earth metal phenolate in the presence of copper as catalyst and in the presence if isoquinoline as diluent at a temperature between about 100.degree. and 200.degree. C. Advantageously the reaction is effected in the presence of about 0.9 to 1.5 mols of potassium or magnesium carbonate, about 1 to 1.2 mols of the phenolate, about 1 to 50 g of copper, copper(I) oxide, copper(I) chloride or copper (I) bromide as catalyst and about 150 to 1,500 ml of isoquinoline per mol of 3-bromo-4-fluoro-toluene.

Abstract: 3,3-Dimethyl-cyclopropane-1,1,2-tricarboxylic acid derivatives of the formula ##STR1## in which R is alkyl, andR.sup.1 and R.sup.2 each is alkoxycarbonyl or cyano, with the proviso that at least one of them is cyano,suitable for use as intermediates in making insecticides, are produced by reacting a .beta.,.beta.-dimethyl-acrylic acid nitrile of the formula ##STR2## with bromine or chlorine at a temperature between about -20.degree. and +50.degree. C.

Abstract: A process for the preparation of a 3-(2,2-dichlorovinyl)-2,2-dimethyl-cyclopropane-1-carboxylic acid or derivative of the formula ##STR1## in which R is hydrogen, alkali metal, ammonium, an equivalent of an alkaline earth metal, alkyl, or a radical customary in the alcohol part of pyrethroids,comprising reacting a 3-formyl-2,2-dimethyl-cyclopropane-1-carboxylic acid derivative of the formula ##STR2## with a dichloromethane derivative of the formula ##STR3## in which R.sup.1 and R.sup.2 each independently is alkyl, phenyl, alkoxy or phenoxy, or together are alkanediyl or alkanedioxy,in the presence of a base at a temperature between about -50.degree. and +50.degree. C. The products are intermediates for the preparation of esters of pyrethroid-like insecticidal activity.