Abstract: Cyclopropanecarboxylic acid alkynyl esters of the formula I ##STR1## wherein R.sub.1 is unsubstituted or substituted phenyl or thienyl, R.sub.2 is hydrogen, alkyl having 1-6 C atoms, alkenyl having 2-6 C atoms, or phenyl or naphthyl which is unsubstituted or substituted by an alkyl or alkoxy group having 1-2 C atoms or by a halogen atom, and R.sub.3 is hydrogen, alkyl having 1-6 C atoms or alkenyl having 2-6 C atoms, are suitable for combating various plant and animal pests, particularly insects, and members of the order Acarina. They can be obtained by reaction of corresponding alkynols with cyclopropanecarboxylic acid or with a reactive functional derivative thereof.

Abstract: The invention provides novel .omega.-(5-alkenylthien-2-yl)alkanecarboxylic acids and their functional derivatives having the formula ##STR1## wherein n is an integer from 1 to 9, inclusive; R.sup.1 is H and R.sup.2 is --OH, or R.sup.1 and R.sup.2 together with the wavy lines represent a keto group; and R.sup.3 is H, C.sub.1 -C.sub.6 straight or branched-chain saturated hydrocarbon, or a pharmaceutically acceptable alkali cation. The 3-oxoalkenyl-substituted compounds of formula (I) are prepared by a Wittig-Horner reaction using a 2-oxoheptylphosphonic acid dialkyl ester and an aldehyde of the formula ##STR2## as starting materials, while the 3-hydroxyalkenyl-substituted compounds are obtained by reduction of the corresponding 3-oxoalkenyl compounds. The esters of formula (I) can also be readily converted to the corresponding acids and salts of formula (I).

Abstract: Disclosed is a process for the preparation of thiophenes having the formula ##STR1## by contacting a compound having the formula ##STR2## with certain amine bases. Other amine bases can be employed when a two-phase reaction system is used.

Abstract: The invention relates to new prostaglandin derivatives of the 6-keto-PGE.sub.1 series, to processes and intermediates for their manufacture and to their use as medicaments.

Abstract: There is described a new process for the preparation of optically active 2-(2',2'-dihalogenovinyl)-cyclopropane-1-carboxylic acids substituted in the 3 position, and derivatives thereof. A racemate of certain cyclobutanones is reacted with a sulfurous acid salt of an optically active base to obtain a mixture of diastereomeric 4-2-(2',2',2'-trihalogenoethyl)-cyclobutane-1-sulfonic acid salts; this mixture is then separated into the pure diastereomeric sulfonic acid salts. Either the pure diastereomeric sulfonic acid salts are converted directly to the desired optically active products, or the optically active cyclobutanones obtained from the pure diastereomeric sulfonic acids salts by decomposition is converted, in the presence of a base to the desired product. Optionally, the product, optically active 2-(2',2'-dihalogenovinyl)-cyclopropane-1-carboxylic acids can be converted to their 1',2'-dibromo derivatives.

Abstract: Novel esters of halo-4-alkenoic acid compounds having pesticidal activity and methods of their preparation.

Abstract: A process is disclosed for preparing alpha-thienylacetic acid, alkyl esters and salts thereof by carbonylation of 2-chloromethylthiophene, characterized in that 2-chloromethylthiophene and carbon monoxide are reacted under atmospheric pressure and at a temperature ranging from 0.degree. to 60.degree. C., in an aqueous-alcoholic solution in the presence of a catalyst selected from the class consisting of Co.sub.2 (CO).sub.8, MCo(CO).sub.4 where M is selected from the class consisting of Na and K, and a system comprising a cobalt salt (such as cobaltous chloride), a ferro-manganese alloy and at least one sulphur-containing promoter (such as the alkaline sulphides and thiosulphates), and in the presence of an inorganic base, and the separating the alpha-thienylacetic acid from the resulting salt and/or ester obtained.

Abstract: Dichlorovinylcyclobutanones of the formula ##STR1## wherein one of R.sub.1 and R.sub.2 is methyl and the other is hydrogen or methyl, or R.sub.1 and R.sub.2 together are alkylene having 2-4 C atoms, X is chlorine and Y is hydrogen, or X is hydrogen and Y is chlorine; processes for preparing them, and their use as intermediates for producing pesticidal compositions.

Abstract: The invention concerns novel pesticidal esters of the pyrethrin or pyrethroid type in which the methylene group bonded to the ester carbonyl and/or ester oxygen bears a fluorine substituent. The compounds of the invention are active against insect pests including flies, moths, aphids and beetles and acarina pests including ticks.

Abstract: Compounds of the formula (II): ##STR1## wherein X is halogen, hydroxyl or functionalized hydroxyl; Y is halogen, hydroxyl or alkoxy; R.sup.1 is a carboxylic acid group and ester thereof and amide derivative thereof or cyano; and R.sup.2 is hydrogen, a hydrocarbon, a heterocycle, a carboxylic acid group, a carboxylic acid ester, a carboxylic acid amide derivative, acyl, cyano, isocyano or an optionally substituted imine of the formula --CH.dbd.NZ or --N.dbd.CH.sub.2 wherein Z is hydrogen, alkyl, aryl, sulphonyl, --SR.sup.a, sulphoxide --SR.sup.a, or sulphonate --SR.sup.a wherein R.sup.a is alkyl of 1 to 6 carbon atoms or aryl, are useful as intermediates for the ultimate production of penicillins or cephalosporins.

Abstract: 5-Substituted indan-2-carboxylic acids and functional derivatives thereof having inflammation-reducing properties have the general formula ##STR1## in which R is a phenyl, phenyl-lower alkenyl, phenyl-lower alkyl, phenyl substituted by at least one of the halogens, lower alkyl, lower alkoxy, acetamido, amino, lower dialkylamino, nitro, phenyl, lower alkylsulfonyl, lower dialkylaminosulfonyl and sulfamido, cyclohexyl, furyl, lower alkylfuryl, thienyl, halothienyl, lower alkylthienyl, or pyridyl group and R' is a hydroxyl, lower alkoxy, lower dialkylaminoalkoxy, cinnamoylamido lower alkoxy, 2-hydroxyethylamino, amino or lower dialkylaminoalkyl amino group. Besides the esters and amides, the functional derivatives of the acids include the pharmacologically acceptable salts of the above compounds. The compounds are also of low toxicity, have analgesic activity and exert an antipyretic effect.

Abstract: There are disclosed processes for preparing an aromatic acetic acid by the reaction of an aromatic aldehyde with a combination of a trihalomethane and an alkanethiol, and by the reaction of an alcohol derivative (2,2,2-trihalo-1-arylethanol) with an alkanethiol, in the presence of a base in a mixed medium of water and an aprotic polar solvent.

Abstract: Process for the preparation of a series of thiophene derivatives, from which 2-thiopheneacetic acid derivatives can easily be prepared, in high yields and selectivity by using substituted or unsubstituted 2-acetylthiophenes as the starting materials by easy operations. 2-Thiopheneacetic acid derivatives are very useful compounds as the chemical modifier of penicillin and cephalosporin. In the course of the reaction, 2-(dihaloacetyl)thiophenes are formed which are valuable intermediates for the production of not only 2-thiopheneacetic acids but also thioprofenic acid which is known as an anti-inflammatory agent.

Abstract: Preparation of a 3-thienylmalonic acid or a diester thereof comprising reacting in a polar solvent in the presence of a copper (I) halide a thiophene compound of formula: ##STR1## wherein X=I or Br,R.sub.1 =H or a C.sub.1-4 alkyl group,R.sub.2 =H or a C.sub.1-2 alkyl group andR.sub.3 =H or a C.sub.1-2 alkyl group,with the proviso that R.sub.2 and R.sub.3 cannot be an alkyl group simultaneously, with a mono-deprotonated methylene compound of formula: ##STR2## wherein a cation is present and Z'=Z" is CN or COOR in which R is a C.sub.1-4 alkyl group, or Z'=CN and Z"=COOR' in which R' is a C.sub.1-2 alkyl group, followed by hydrolysis by methods known per se to get the corresponding free acid.

Abstract: Compounds of the formulae Ia, Ib, IIa and IIb ##STR1## are described, wherein R represents alkyl, haloalkyl, benzyl, naphthyl or substituted or unsubstituted phenyl and one of R.sub.1 and R.sub.2 represents methyl and the other represents hydrogen or methyl, or R.sub.1 and R.sub.2 together represent alkylene of 2 or 3 carbon atoms. The compound of the formulae Ia, Ib, IIa and IIb are valuable intermediates for the manufacture of pyrethroid pesticides or precursors thereof.

Abstract: 2,2-Dimethyl-3-(2'-perfluoroalkyl-2'-perhaloalkyl-vinyl)-cyclopropane of the formula ##STR1## in which R is --COOR.sup.2, --COOH, --CO--Halogen, --CN or --CO--CH.sub.3,R.sup.1 is fluorine or CF.sub.3,R.sup.3 is fluorine, chlorine, bromine or R.sup.1 CF.sub.2 --, andR.sup.2 is the radical of an alcoholwhich possess arthropodicidal properties. These compounds can be produced by adding a compound of the formula ##STR2## to an olefin of the formula ##STR3## to produce a compound of the formula ##STR4## and dehydrohalogenating said compound. This compound may be hydrolyzed, saponified or esterified, depending upon the particular derivative desired.

Abstract: A process for the preparation of 3-substituted thiophenes which involves cyclization of a novel intermediate, avoids the use of previously employed expensive starting materials. The thiophenes are useful for the preparation of penicillins and cephalosporins.The process is for the preparation of a thiophene of formula (I): ##STR1## where R.sup.1 represents a carboxylic acid group, or an ester or amide thereof or a nitrile group; R.sup.2 represents a group suitable for use as an .alpha.-substituent in the side-chain of a penicillin or cephalosporin; which comprises treating a compound of formula (II): ##STR2## wherein X represents halogen or optionally functionalized hydroxyl, Y represents halogen, hydroxyl, or alkoxy; with a source of nucleophilic sulphur under basic conditions.

Abstract: A method of reducing the content of a haloethynyl-containing impurity in a synthetic dihaloethenylcyclopropanecarboxylate by treatment with a phosphite under condition allowing the haloethynyl-containing impurity and phosphite to chemically interact, and thereafter recovering the dihaloethenylcyclopropanecarboxylate from the reaction mixture is disclosed.

Abstract: Disclosed are novel polymeric quaternary ammonium salts containing specific di-tertiary amino substituted cationic recurring units. Said salts are useful as dyeing and finishing agents, especially for dyeing textile materials, such as polyacrylonitrile fiber materials, as dispersing agents and emulsifiers, as antistatic, antimicrobial and flocculating agents and as precipitants.

Abstract: A process for preparing a 2-thio-2-substituted-alkanoic acid derivative represented by the formula (I) ##STR1## wherein A, R, R.sup.3 and R.sup.4 are as defined hereinafter, which comprises condensing an aldehyde compound of the formula (V)A--CHO (V)wherein A is as defined hereinafter, with a haloform of the formula CHX.sub.3 wherein X is as defined hereinafter and a mercaptan compound of the formula (IV)R.sup.3 SH (IV)wherein R.sup.3 is as defined hereinafter, in the presence of a base to produce a 2-(arylthio or alkylthio)-2-substituted-acetic acid of the formula (III) ##STR2## wherein A and R.sup.3 are as defined hereinafter, and reacting the resulting 2-(arylthio or alkylthio)-2-substituted-acetic acid of the formula (III) with an alkylating agent represented by the formula (II)RZ (II)wherein R and Z are as defined hereinafter, in the presence of at least 2 mols of a base per mol of the 2-(arylthio or alkylthio)-2-substituted-acetic acid, to form the compound of the formula (I) wherein R.sup.

Abstract: Perhaloalkylvinylcyclopropanecarboxylates having the general formula ##STR1## are disclosed wherein one of Y and Z is a perhaloalkyl group. Compounds in which R is hydroxy, halogen or lower alkoxy are novel intermediates for preparation of insecticidal esters in which R is --OR.sup.1 where R.sup.1 is a wide variety of alcohol residues. The insecticidal efficacy and preparation of the compounds and intermediates therefor are described and exemplified.

Abstract: Aromatic acetic acid derivatives having a sulfur atom at the alpha-position, and a process for their preparation. Useful drugs can be produced from derivatives. erivatives.

Abstract: Novel derivatives of glycolic and glyoxylic acid are disclosed which inhibit glycolic acid oxidase and thus are useful in the treatment and prevention of calcium oxalate urolithiasis (calcium oxalate kidney and bladder stone disease).

Abstract: 9-substituted, 4- or 6-fluorine substituted retinoic acid derivatives useful as antitumor agents and in the treatment of acne as well as a method for their manufacture are disclosed. Substituents at the 9-position include substituted phenyl, thienyl and furyl groups.

Abstract: Novel 9-substituted or unsubstituted thienyl-3,7-dimethyl-nona-2,4,6,8-tetraene derivatives, useful as antitumor agents as well as processes for their preparation and novel intermediates are disclosed.

Abstract: A novel 2-[4-(3-methyl-2-thienyl)phenyl]propionic acid and a pharmaceutically acceptable salt thereof. These compounds are useful for treating symptoms of inflammation and pain in mammals including man. This disclosure relates to such compounds, a process for producing the same, a pharmaceutical composition containing such a compound and a method for treating symptoms of inflammation and pain.

Abstract: A process for the activation of carboxylic acids which is useful for the subsequent conversion of said carboxylic acids into their corresponding amides or esters, based on reacting a 2-oxazolidinone with phosphorus pentachloride and subsequent addition of a salt of the carboxylic acid to be activated.

Abstract: This invention provides new compounds of formula I, ##STR1## wherein R.sub.1 is hydrogen, chlorine or lower alkyl,R.sub.2 is lower alkyl,R.sub.3 is lower alkyl, each ofA and B is hydrogen, orA and B together form a bond,useful as luteinizing hormone secretion inhibitors, e.g. for the treatment of prostate hypertorphy.

Abstract: Process for the preparation of a series of thiophene derivatives, from which 2-thiopheneacetic acid derivatives can easily be prepared, in high yields and selectivity by using substituted or unsubstituted thiophenes as the starting materials by easy operations. 2-Thiopheneacetic acid derivatives are very useful compounds as the chemical modifier of penicillin and cephalosporin. Novel compounds, i.e. .alpha.-arylthio-2-thiopheneacetic acids are also disclosed. These compounds are useful as the intermediates of the synthesis of 2-thiopheneacetic acids.

Abstract: An .alpha.-(2-thienyl)propionic acid can easily be prepared in a high yield and high selectivity by reacting a 2-(dihaloacetyl)thiophene which is easily obtainable by acetylation and halogenation of a substituted or unsubstutitued thiophene, with a methylmetal compound and then reacting an alkali metal hydroxide with the reaction product. .alpha.-(2-Thienyl)propionic acids are useful compounds from which, for example, thioprofenic acid can easily be prepared. Thioprofenic acid is known as an anti-inflammatory agent. As reaction intermediates, 1-(2-thienyl)-1-dihalomethylethanols can be obtained. Which are novel and useful compounds.

Abstract: A novel class of compounds has been prepared comprising the tetrasulfides of C.sub.18 hydrocarbons, C.sub.18 fatty acids, and C.sub.18 fatty and alkyl and triglyceride esters. These tetrasulfides are useful as extreme pressure lubricant additives and show potential as replacements for sulfurized sperm whale oil.

Abstract: A process for the preparation of a dihalogenovinylcyclopropanecarboxylic acid or an ester thereof, of the formula ##STR1## in which Hal each independently is fluorine, chlorine or bromine,R.sup.1 and R.sup.2 each independently is hydrogen or C.sub.1-4 -alkyl, or R.sup.1 and R.sup.2 together with the adjacent carbon atoms form a cycloaliphatic ring with up to 7 carbon atoms, andR.sup.3 is hydrogen, C.sub.1-4 -alkyl or optionally substituted arylmethyl or hetero-arylmethyl,which comprises reacting a 3-chloro-2-(2',2'-dihalovinyl)-propanecarboxylic acid ester of the formula ##STR2## in which R.sup.4 is C.sub.1-4 -alkyl or optionally substituted arylmethylor hetero-arylmethyl,with a base. The propane carboxylic acid esters are new and may be formed in situ by reacting a 3-(2',2'-dihalovinyl)-.gamma.-butyrolactone of the formula ##STR3## with a chlorinating agent and then with an alcohol of the formula R.sup.4 --OH.

Abstract: Esters of .alpha.-indenyl substituted aliphatic acids, intermediates therefor, synthesis thereof, and the use of said esters and compositions thereof for the control of pests.

Abstract: Process for preparing an organic compound of the formula R.sup.2 R.sup.2 CFC(O)R.sup.3, which process comprises contacting and reacting in a reaction mixture which includes an inert solvent, at a temperature of -40.degree. C. to -100.degree. C., ROF and ##STR1## R is polyfluoroperhaloalkyl of 1-6 carbon atoms or FOCF.sub.2 ; R.sup.1 is hydrocarbyl of 1-6 carbon atoms;each R.sup.2 is selected from H, alkyl of 1-17 carbon atoms, cycloalkyl of 3-6 carbon atoms, aryl, heteroaryl and such alkyl, cycloalkyl, aryl and heteroaryl substituted by halogen or alkoxy of 1-6 carbon atoms;R.sup.3 is selected from H, alkyl and haloalkyl of 1-16 carbon atoms, cycloalkyl of 3-10 carbon atoms, aryl and haloaryl, OSi(R.sup.1).sub.3, OH, NH.sub.2, alkoxy of 1-6 carbon atoms, aryloxy, NHR.sup.1 and NR.sup.1.sub.2 wherein R.sup.1 is alkyl of 1-6 carbon atoms, N-arylamino and nitrogen or sulfur heterocyclic of 4-5 carbon atoms;R.sup.3 and one R.sup.2 taken together is a diradical which with the C.dbd.

Abstract: Disclosed is a process for increasing the proportion of a desired enantiomer of a 2-arylpropionic acid which comprises heating at a temperature of at least 80.degree. C. a mixture comprising an inert liquid organic diluent and a salt of the 2-arylpropionic acid with an enantiomer of a chiral organic nitrogenous base, the base and the diluent being such that the salt of the racemic acid has a solubility of 0.1 to 10% w/v in the diluent at the operating temperature and in which process a proportion of the salt is undissolved in the diluent, whereby a proportion of one optical isomer of the acid component of the salt is converted into its enantiomer, and collecting the salt of which the acid component has an increased proportion of that enantiomer.

Abstract: Novel derivatives of glycolic and glyoxylic acid are disclosed which inhibit glycolic acid oxidase and thus are useful in the treatment and prevention of calcium oxalate urolithiasis (calcium oxalate kidney and bladder stone disease).

Abstract: Benzyl esters and thiolesters of 4-aryl-3-butenoic acids, intermediates therefor, synthesis thereof, and the use of said esters and thiolesters for the control of pests.

Abstract: Antibacterial 7.beta.-arylmalonamido-7.alpha.-methoxy-3-optionally alkylated thiadiazolylthiomethyl-1-oxadothiacephalosporins of the following formula: ##STR1## (wherein Ar is 2-thienyl, 3-thienyl, phenyl, p-hydroxyphenyl, p-acyloxyphenyl or p-protected hydroxyphenyl;COB.sup.1 and COB.sup.2 each is carboxy, protected carboxy or a carboxylate salt; andR is hydrogen or lower alkyl),processes for preparing said compounds, a pharmaceutical or veterinary composition comprising the said compounds and pharmaceutical carrier and a method for treating or preventing human or veterinary infectious diseases comprising administering the said compound.

Abstract: Novel esters of ether and thioether substituted cyclopropanecarboxylic acids, synthesis thereof, and intermediates therefor, such esters being useful as pesticides.

Abstract: The invention provides certain 4-keto-phenoxyacetic acids and their oximes of the formula: ##STR1## in which A is selected from oxygen and sulphur,Z is selected from oxygen and the group NOH, andX.sub.1 and X.sub.2 are radicals independently selected from hydrogen, halogen and methyl, with the proviso that the benzene nucleus is never substituted by two halogen atoms in ortho-position with respect of one another, and pharmaceutically acceptable alkaline and amine addition salts thereof.

Abstract: The process for manufacturing thienyl-2 acetic acid from acetylthiophene comprises condensing acetylthiophene at a temperature below 120.degree. C. with an excess of a C.sub.4 to C.sub.8 aliphatic primary amine or with a cyclic amine, in the presence of an acid catalyst and removing the water formed, so as to obtain the corresponding imine. The imine is reacted with excess sulfur at a temperature equal to or below 100.degree. C. in a basic and aprotic solvent to produce the corresponding thioamide. The thioamide is hydrolyzed by the action of an excess of a strongly alkaline base in a C.sub.4 to C.sub.8 alcohol or in ethylene glycol, if necessary in the presence of water, so as to obtain an alkali salt of thiophene-2 acetic acid. Finally the latter is treated with a strong acid in aqueous solution to liberate the thienyl-2 acetic acid.

Abstract: Compounds of the general formula I ##STR1## wherein n represents 0, 1 or 2, A represents oxygen or sulphur, Z represents oxygen or hydroxyimino, X represents hydrogen, or halogen, the dotted lines represent bonds which may be unsaturated or saturated, R.sub.1 and R.sub.2 each represent hydrogen or alkyl, and R.sub.3 represents hydrogen, halogen or methyl, and R.sub.4 represents a hydrogen atom, or R.sub.3 and R.sub.4 together with the two carbon atoms to which they are attached represent benzene, and their pharmaceutically acceptable salts are useful in therapy, in particular as uricosuric agents or as diuretic and uricosuric agents.

Abstract: 3-Thienyl-acetate derivatives of the general formula: ##STR1## wherein R.sub.1 represents an alkyl, a cycloalkyl or an aralkyl radical, R.sub.2 represents hydrogen or R.sub.1 and R.sub.2, when they are taken together to form a cyclic group with the carbon atom to which they are attached, represent a polymethylene radical having from 2 to 5 carbon atoms, are prepared from a mixture consituted by a compound of the formula: ##STR2## wherein R.sub.3 has the meaning given above and an organic halide of the formula:R.sub.4 Xwherein X represents fluorine, chlorine, bromine or iodine and R.sub.4 represents an alkyl, cycloalkyl or aralkyl radical or --CH.sub.2 (CH.sub.2).sub.n X in which n is an integer in the range of from 1 to 4 inclusive and X has the meaning given above, which mixture is added to an alkali metal hydride in dimethylformamide, at a temperature between -20.degree. C. and -5.degree. C., and allowed to react, in one step, at a temperature between -20.degree. C. and -5.degree. C.

Abstract: A compound of the formula I: ##STR1## wherein: R is substituted or unsubstituted C.sub.1-6 alkyl, a substituted or unsubstituted aromatic ring, a heterocyclic ring, a cycloalkyl group or a fused ring system,R.sup.1 is hydrogen, lower alkyl, cycloaliphatic or heterocyclic ring, andX is a halogen atom.

Abstract: A method for preparing thienylacetic acid and its derivatives is disclosed, wherein a glyoxylic ester is made to react with hydrazine, and after with potash. Advantageously, the glyoxylic ester is prepared by condensation of a monoester monochloride of oxalic acid upon a thiophenic derivative, in the presence of titanium chloride.The so obtained products are useful as organic synthesis intermediaries for various products of pharmaceutical type.

Abstract: [1-Oxo-2-aryl or thienyl-2-substituted-5-indanyloxy (or thio)]alkaoic acid, derivatives thereof, their salts, esters and amides are disclosed. The products display a dual pharmaceutical utility in that they exhibit diuretic, saluretic and uricosuric activity. Also disclosed are processes for the preparation of such [1-oxo-2-aryl or thienyl-2-substituted-5-indanyloxy (or thio)]alkanoic acids, pharmaceutical compositions comprising therapeutically effective amounts of such compounds and methods of treatment comprising administering such compounds and compositions.

Abstract: 9-Substituted, 4- or 6-fluorine substituted retinoic acid derivatives useful as antitumor agents and in the treatment of acne as well as a method for their manufacture are disclosed. Substituents at the 9-position include substituted phenyl, thienyl and furyl groups.

Abstract: .omega.-NOR-CYCLOALKYL-13,14-DEHYDRO-PROSTAGLANDIN COMPOUNDS, SPECIFICALLY 13,14-DEHYDRO-17-CYCLOHEXYL-20,19,18-TRINOR-PGF.sub.2.alpha. having antiulcer and luteolytic activity, are disclosed.

Abstract: A process is described whereby esters of 3-(2,2,2-trichloroethyl)-2,2-dimethylcyclopropane-1-carboxylic acid are prepared predominantly in their cis isomer form. The process comprises treating a 4,6,6,6-tetrachloro-3,3-dimethylhexanoate with an alkali metal tert-alkoxide under controlled conditions of temperature in the presence of a defined solvent-cosolvent mixture. The products of the process are intermediates in the production of pyrethroid insecticides.

Abstract: 3-Thienyl-acetate derivatives of the general formula: ##STR1## wherein R.sub.1 represents an alkyl, a cycloalkyl or an aralkyl radical, R.sub.2 represents hydrogen or R.sub.1 and R.sub.2, when they are taken together to form a cyclic group with the carbon atom to which they are attached, represent a polymethylene radical having from 2 to 5 carbon atoms, are prepared from a mixture consituted by a compound of the formula: ##STR2## wherein R.sub.3 has the meaning given above and an organic halide of the formula:R.sub.4 Xwherein X represents fluorine, chlorine, bromine or iodine and R.sub.4 represents an alkyl, cycloalkyl or aralkyl radical or --CH.sub.2 (CH.sub.2).sub.n X in which n is an integer in the range of from 1 to 4 inclusive and X has the meaning given above, which mixture is added to an alkali metal hydride in dimethylformamide, at a temperature between -20.degree. C. and -5.degree. C., and allowed to react, in one step, at a temperature between -20.degree. C. and -5.degree. C.