- Transformation of 3-(2,2-Dichloroethenyl)-2,2-dimethylcyclopanecarboxylates to the Corresponding 2,2-Dibromoethenyl Analogs by Halogen Exchange Reaction
-
The title transformation is effected with aluminium tribromide or related reagents in over 80percent yields without cis-trans isomerization or epimerization.Efficient removal of hydrogen bromide is essential for optimum yields of the desired products.Use of boron tribromide instead of aluminium tribromide results in opening of the cyclopropane ring with no halogen exchange.
- Matsui, Kiyohide,Saito, Akemi,Kondo, Kiyosi
-
-
Read Online
- Synthesen von (1R)-cis-3-(2',2'-Dihalovinyl)-2,2-dimethylcyclopropancarbonsaeuren via Favorskii-Umlagerung von optisch aktiven Cyclobutanonen
-
The cis-cyclobutanones 7 are resolved by means of optically active amine salts of their sodium hydrogen sulfite adducts.The desired (1R)-cis-carboxylic acids 9 are obtained from the (+)-cis-cyclobutanones 7 via Favorskii-rearrangement and HX-elimination.The recycling of undesired (-)-cis-cyclobutanones 7 is carried out in good yield by their racemization, thus rendering the total synthesis 1+2->9 chirally economic.
- Greuter, Hans,Dingwall, John,Martin, Pierre,Bellus, Daniel
-
-
Read Online
- Free radical addition of haloalkanes to polymer bound olefins and its application to the solid-phase synthesis of pyrethroids
-
Polymer bound olefins undergo free radical initiated 1,2-addition when reacted with a variety of haloalkanes. The strategy could be applied successfully to the solid-phase synthesis of dihaloethenylcyclopropane carboxylic acids which are the key fragments of synthetic pyrethroids.
- Kumar,Chakravarthy, P.Pawan,Shesha Rao,Reddy, P.Sunder Ram,Yadav
-
-
Read Online
- Characterization of a novel thermophilic pyrethroid-hydrolyzing carboxylesterase from Sulfolobus tokodaii into a new family
-
A novel gene ST2026 encoding a putative carboxylesterase from the thermophilic crenarchaeota Sulfolobus tokodaii (named EstSt7) was cloned and functionally overexpressed in Escherichia coli. The recombinant enzyme was purified to homogeneity after heat treatment, Ni-NTA affinity and Superdex-200 gel filtration chromatography. EstSt7 showed maximum activity at 80 C over 30 min and had a half-life of 180 min at 90 C. Its enzymatic activity was stable in the pH range of 8.0-10.0 with an optimum at 9.0. The enzyme exhibited significant esterase activity toward various p-nitrophenyl esters and the most preferable substrate was p-nitrophenyl butyrate (kcat/Km of 246.3 s-1 mM-1). In addition, EstSt7 showed high activity and stability against organic solvents (20% and 50% v/v) and detergents (1% and 5% v/v). Furthermore, EstSt7 could efficiently hydrolyze a wide range of synthetic pyrethroids including fenpropathrin, permethrin, cypermethrin, cyhalothrin, deltamethrin and bifenthrin, which makes it a potential candidate for the detoxification of pyrethroids for the purpose of biodegradation. Sequence alignment, phylogenetic analysis and comparison of the conserved motif reveal that this novel carboxylesterase EstSt7 should be grouped into a new bacterial lipase and esterase family.
- Wei, Tao,Feng, Shengxue,Shen, Yulong,He, Peixin,Ma, Geli,Yu, Xuan,Zhang, Fei,Mao, Duobin
-
p. 225 - 232
(2013/10/21)
-
- Syntheses of racemic and scalemic cis-chrysanthemic acid from β,γ-unsaturated cyclohexanol
-
2,2,5,5-Tetramethylcyclohexane-1,3-dione is a valuable starting-material precursor of cis-chrysanthemic acid. The (1S)-stereoisomer is a precursor of pyrethrin I, the most active natural insecticide from Chrysanthemum cinerariifolium, whereas the (1R)-stereoisomer is efficiently transformed to deltamethrin, the most active commercially available pyrethroid insecticide. Several intermediates have been identified and used with variable success for that purpose.
- Krief, Alain,Jeanmart, Stéphane,Gondal, Humaira Y.,Kremer, Adrian
-
p. 2123 - 2167
(2013/02/23)
-
- Synthesis and biological evaluation of pyrethroid insecticide-derivatives as a chemical inducer for Bdnf mRNA expression in neurons
-
Brain-derived neurotrophic factor (BDNF) plays a fundamental role in neuronal synaptic plasticity. A decrease of plasticity in the brain may be related to the pathogenesis of neurodegenerative or psychiatric disorders. Pyrethroid insecticides, which affect sodium channels in neurons, are widely used to control insect pests in agriculture and in the home. We previously found that deltamethrin (DM), a type II pyrethroid, increased Bdnf mRNA expression in cultured rat cortical neurons. However, the cyano group at the α-position of type II pyrethroids is likely susceptible to hydrolytic degradation and, its degraded product, hydrogen cyanide, could generate a cellular toxicity in the human body. To determine if the cyano group is required for the Bdnf exon IV-IX (Bdnf eIV-IX) mRNA expression induced by type II pyrethroids, for this study we synthesized a series of derivatives, in which the cyano group at the α-position was replaced with an ethynyl group. Then we added various substituents at the terminal position of the ethynyl group, and biologically evaluated the effects of these derivatives on Bdnf eIV-IX mRNA expression. These ethynyl derivatives induced the Bdnf eIV-IX mRNA expression in a concentration-dependent manner, at varying levels but lower levels than that evoked by DM. The mechanisms for the Bdnf induction and the morphological changes of neurons were the same whether the cyano or ethynyl group was included in the compounds.
- Matsuya, Yuji,Ihara, Daisuke,Fukuchi, Mamoru,Honma, Daisuke,Itoh, Kiyoshi,Tabuchi, Akiko,Nemoto, Hideo,Tsuda, Masaaki
-
body text
p. 2564 - 2571
(2012/05/20)
-
- Selected regiocontrolled transformations applied to the synthesis of (1S)-cis-chrysanthemic acid from (1S)-3,4-epoxy-2,2,5,5-tetramethylcyclohexanol
-
(1S)-cis-Chrysanthemic acid has been prepared in a few steps with complete control of the relative and absolute stereochemistry using regiocontrolled epoxide ring opening, diol mono-oxidation and cyclopropanation. The Royal Society of Chemistry.
- Krief, Alain,Gondal, Humaira Y.,Kremer, Adrian
-
scheme or table
p. 4753 - 4755
(2009/03/12)
-
- Diastereoselective bromination of compounds bearing a cyclohex-3-enol moiety: Application to the enantioselective synthesis of (1R)-cis-deltamethrinic acid
-
(Chemical Equation Presented) (1R)-cis-Chrysanthemic acid has been prepared in a few steps with complete control of the relative and absolute stereochemistry. Some mechanistic aspect of the addition of bromine to the C,C double bond of 2,2,5,5-tetramethylcyclohex-3-enol is disclosed.
- Krief, Alain,Jeanmart, Stephane,Kremer, Adrian
-
experimental part
p. 9795 - 9797
(2009/04/07)
-
- Molecular cloning, purification, and biochemical characterization of a novel pyrethroid-hydrolyzing esterase from Klebsiella sp. strain ZD112
-
The gene encoding pyrethroid-hydrolyzing esterase (EstP) from Klebsiella sp. strain ZD112 was cloned into Escherichia coli and sequenced. A sequence analysis of the DNA responsible for the esfP gene revealed an open reading frame of 1914 bp encoding for a protein of 637 amino acid residues. No similarities were found by a database homology search using the nucleotide and deduced amino acid sequences of the esterases and lipases. EstP was heterologously expressed in E. coli and purified. The molecular mass of the native enzyme was approximately 73 kDa as determined by gel filtration. The results of sodium dodecyl sulfate - polyacrylamide gel electrophoresis and the deduced amino acid sequence of EstP indicated molecular masses of 73 and 73.5 kDa, respectively, suggesting that EstP is a monomer. The purified EstP not only degraded many pyrethroid pesticides and the organophosphorus insecticide malathion, but also hydrolyzed ρ-nitrophenyl esters of various fatty acids, indicating that EstP is an esterase with broad substrates. The Km for trans- and cis-permethrin and kcat/Km values indicate that EstP hydrolyzes both these substrates with higher efficiency than the carboxylesterases from resistant insects and mammals. The catalytic activity of EstP was strongly inhibited by Hg2+, Ag+, and ρ-chloromercuribenzoate, whereas a less pronounced effect (3-8% inhibition) was observed in the presence of divalent cations, the chelating agent EDTA, and phenanthroline.
- Wu, Pei C.,Liu, Yu H.,Wang, Zhuo Y.,Zhang, Xiao Y.,Li, He,Liang, Wei Q.,Luo, Na,Hu, Ji M.,Lu, Jia Q.,Luan, Tian G.,Cao, Li X.
-
p. 836 - 842
(2007/10/03)
-
- Purification and characterization of a novel pyrethroid hydrolase from Aspergillus niger ZD11
-
The pyrethroid pesticides residues on foods and environmental contamination are a public safety concern. Pretreatment with pyrethroid hydrolase has the potential to alleviate the conditions. For this purpose, a fungus capable of using pyrethroid pesticides as a sole carbon source was isolated from the soil and characterized as Aspergillus niger ZD11. A novel pyrethroid hydrolase from cell extract was purified 41.5-fold to apparent homogeneity with 12.6% overall recovery. It is a monomeric structure with a molecular mass of 56 kDa, a pl of 5.4, and the enzyme activity was optimal at 45°C and pH 6.5. The activities were strongly inhibited by Hg2+, Ag+, and p-chloromercuribenzoate, whereas less pronounced effects (5-10% inhibition) were observed in the presence of the remaining divalent cations, the chelating agent EDTA and phenanthroline. The purified enzyme hydrolyzed various insecticides with similar carboxylester. trans-Permethrin is the preferred substrate.
- Liang, Wei Q.,Wang, Zhuo Y.,Li, He,Wu, Pei C.,Hu, Ji M.,Luo, Na,Cao, Li X.,Liu, Yu H.
-
p. 7415 - 7420
(2007/10/03)
-
- Process for racemizing optically active vinyl-substituted cyclopropanecarboxylic acid compound
-
There is disclosed a process for the racemization of a vinyl-substituted cyclopropanecarboxylic acid or a derivative thereof, which is characterized by reacting an optically active vinyl-substituted cyclopropanecarboxylic acid compound of formula (1): 1wherein R1, R2, R3 and R4 each independently represent a hydrogen atom, a halogen atom, alkyl which may be substituted having 1-4 carbon atoms, aryl which may be substituted, or alkoxycarbonyl which may be substituted, or R1 and R2 are bonded to form an alkylene group, which may be substituted; and wherein X represents hydroxyl, a halogen atom, alkoxy which may be substituted having 1-20 carbon atoms, or aryloxy which may be substituted, with a nitric compound or a nitrogen oxide.
- -
-
-
- Process for producing cyclopropanecarboxylates
-
There is disclosed a process process for producing a cyclopropanecarboxylate of formula (1): 1which process comprises reacting cyclopropanecarboxylic acid of formula (2): 2with a monohydroxy compound of formula (3): R6OH??(3),in the presence of a catalyst compound comprising an element of to Group 4 of the Periodic Table of Elements.
- -
-
-
- Process for the preparation of cyclopropane carboxylic acids
-
Preparation of cyclopropane carboxylic acids usable as intermediates and of formula (II), wherein R1represents halogen, preferably Cl or Br, or haloalkyl, preferably CF3, and X2represents halogen, preferably Cl or Br, where R1or X2may be the same or different, and wherein the configuration of (II) is predominantly Z for R1=CF3and X2=Cl; by reacting, in the presence of a catalyst, a compound of formula (I), wherein R1and X2are as defined, and X1represents halogen, preferably Cl or Br, where R1, X1and X2may be the same or different, with a compound which is a hydrogen donor.
- -
-
-
- Practical chemo-enzymatic process for the preparation of (1R,cis)-2-(2,2-dihaloethenyl)-3,3-dimethylcyclopropane carboxylic acids
-
A practical chemo-enzymatic process for the preparation of optically active (1R,cis)-2-(2,2-dichloro (or dibromo)ethenyl)-3,3-dimethylcyclopropane carboxylic acids (permethrinic or deltamethrinic acids) from racemic 1,1,1-trichloro-2-acetoxy-4-methyl-3-pentene is described. The key intermediate, enantiopure (R)-1,1,1-trichloro-2-hydroxy-4-methyl-3-pentene, is prepared by a lipase catalysed kinetic resolution of the racemic acetate. The reaction mixture, containing (R)-alcohol and the unreacted (S)-acetate, is directly acetylated by a haloacetyl halide, and the products are separated by distillation. The (S)-acetate is racemized, and the (R)-haloacetate is transformed to the corresponding glycinate hydrochloride, followed by diazotization to (R)-1,1,1-trichloro-4-methyl-3-penten-2-yl diazoacetate. The stereoselective carbenic dediazotization of the (R)-diazoacetate furnishes the optically active (1R,4R,5S)-6,6-dimethyl-4-trichloromethyl-3-oxobicyclo[3.2.0]hexan-2-one, which is transformed to the desired enantiopure (1R,cis)-permethrinic or deltamethrinic acid in high optical yield (>99% ee) and overall chemical yield of 10-15%.
- Fishman, Ayelet,Kellner, Dorit,Ioffe, David,Shapiro, Evgeny
-
-
- Enzyme catalysed kinetic resolution of racemic 2,2-dimethyl-3-(2,2- disubstituted vinyl) cyclopropane carboxylic acids anchored on polymer supports
-
Kinetic resolution of trans-substituted cyclopropane carboxylic acids anchored on a solid support by lipase is described.
- Nanda,Bhaskar Rao,Yadav
-
p. 5905 - 5908
(2007/10/03)
-
- Development of Immunoassays for Type II Synthetic Pyrethroids. 1. Hapten Design and Application to Heterologous and Homologous Assays
-
Immunoassays differing in selectivities for pyrethroid insecticides have been developed for the detection of type II pyrethroids, including deltamethrin, cypermethrin, and λ-cyhalothrin. Two approaches were employed in hapten synthesis to raise antibodies with different cross-reactions: (1) use of three spacer attachment points to offset different parts of molecules from the points of attachment and (2) use of linkers with and without bulky groups in the enzyme conjugate to reduce antibody affinities for the spacer arm in the immunoassay. The first approach resulted in the preparation of three series of haptens with a spacer attached (1) at the aromatic moiety of pyrethroid, (2) through the middle of the molecule, and (3) at the cyclopropane moiety. Haptens based on the derivatives of the pyrethroid metabolites were also prepared. The second approach involved the use of a linker with a bulky (cyclohexane ring) functionality for preparation of an enzyme conjugate. While most combinations of antibody and conjugate could be used in immunoassays for detection of deltamethrin in the 10-100 μg/L range, in most cases the limits of detection of the assays (for total isomers of a particular target pyrethroid) were lowered 10-50 fold by treatment of the pyrethroid standards with dilute alkali to produce a different isomer mix. Fifteen antisera prepared using 8 haptens were each screened with 14 peroxidase conjugates, and 26 antibody/conjugate combinations were selected for further study on the basis of the assay sensitivity, dynamic behavior, and specificity for deltamethrin, cypermethrin, and cyhalothrin. These immunoassays provided 50% inhibition of antibody binding (IC50) values between 1.5 and 4.2 μg/L of isomerized total deltamethrin and limits of detection of 0.2-0.7 μg/L. The most sensitive immunoassay for total deltamethrin was obtained using cypermethric acid-KLH as the immunogen and a conjugate based on a derivative of cypermethrin coupled through the middle of the molecule to peroxidase. These provided an IC50 of 2 μg/L and a limit of detection of 0.2 μg/L of isomerized total deltamethrin. However, no particular hapten design produced antisera of clearly superior sensitivity or specificity for deltamethrin. Differing cross-reactions with the closely related pyrethroids, deltamethrin, cypermethrin, and cyhalothrin, were obtained, and for several antibodies the cross-reaction as well as the limits of detection could be altered by varying the conjugate combinations. Each of the 12 antibody/enzyme conjugate combinations that sensitively detected deltamethrin were very stereospecific, detecting the αS, 1R cis, (DM1), and αR, 1R cis (DM2) isomers only; the assay sensitivity was greater for the latter isomer.
- Lee, Nanju,McAdam, David P.,Skerritt, John H.
-
p. 520 - 534
(2007/10/03)
-
- Fluorobenzyl esters
-
A compound of formula: STR1 wherein R is selected from hydrogen, cyano, methyl, and ethynyl, and X represents the residue of any carboxylic acid of formula X-COOH which forms an insecticidally active ester with a 3-phenoxybenzyl alcohol. The compounds are useful as insecticides and acaricides.
- -
-
-
- Alkyl 6,6-dimethyl-2-oxo-3-oxabicyclo[3.1.0]hexane-1-carboxylates
-
Lactones of the formula STR1 wherein R is hydrogen or a CX3 group, and each X is a chlorine or bromine atom, are converted to the known cis-3-(2,2-dihalovinyl)-2,2-dimethylcyclopropanecarboxylic acids or lower alkyl esters, from which pyrethroid insecticides are obtained.
- -
-
-
- 2,3-Isopropylidene ribonic acid, 1,4-lactones
-
Racemic carboxylic acids are resolved into their enantiomers using optically active enantiomers of four lactones as resolving agents. The four lactones are 2,3-isopropylidene-ribonic acid-1,4-lactone, 1,2-isopropylideneglucofuranurono-3,6-lactone, 2-hydroxy-3,3-dimethyl-1,4-butyrolactone and 3,4-isopropylidene-arabino-1,5-lactone. Novel diastereoisomeric esters of the acids with the lactones are disclosed.
- -
-
-
- Pesticides
-
New insecticides are of formula: STR1 wherein R1 represents hydrogen or a methyl group; R2 represents hydrogen or a halogeno or lower alkyl group; R3 represents hydrogen or a halogeno or carbo(lower alkoxy) group which contains at least 2 carbon atoms in the lower alkoxy residue when R2 represents methyl; with the proviso that (a) R2 and R3 each represent hydrogen only when R1 represents methyl, (b) when R1 and R3 each represent hydrogen and R2 represents alkyl, that alkyl group contains at least 2 carbon atoms and (c) when R3 represents halogeno, R2 represents hydrogen or halogeno; and R represents a group which forms insecticidal esters with chrysanthemic acid e.g. 5-benzyl-3-furylmethyl, 3-phenoxybenzyl, α-cyano-3-phenoxybenzyl. The esters are prepared by forming the ester linkage conventionally or by a Wittig reaction using a 3-formyl- or 3-acetyl-2,2-dimethyl cyclopropane carboxylic acid esterified with the desired residue or by an alkyl group which is subsequently converted to the desired residue.
- -
-
-
- Process for the preparation of 2,2-dimethyl-3-vinyl-cyclopropanecarboxylic acids and esters
-
A process for the production of 2,2-dimethyl-3-vinyl-cyclopropanecarboxylic acid derivative of the formula STR1 in which R1 is a hydrogen atom, an alkyl group or a radical of an alcohol which can be used in pyrethroids, and X1 and X2 each independently is a halogen atom or a fluorine-substituted alkyl radical, comprising adding (a) a polyhalogenoalkene of the formula STR2 in which X3 and X4 each independently is a halogen atom, to 1-chloro-3,3-dimethyl-pent-4-en-2-one of the formula STR3 in the presence of a catalyst which yields free radicals, or in the presence of a metal salt of the VIII main group or of the sub-group IVa, VIIa or Ib of the periodic system, thereby to obtain a mixture of compounds of the formula STR4 and (b) reacting either or both of such compounds with a base of a formula in which M is an alkali metal or alkaline earth metal, and n is 1 or 2. The end products are known insecticides and intermediates therefor, while the intermediates produced by (a) are novel compounds.
- -
-
-
- Process for the preparation of dihalovinylcyclopropanecarboxylic acids
-
The invention relates to a new process for the preparation of cyclopropanecarboxylic acids of the formula (I) STR1 wherein X and Y independently stand for halogen, by the alkaline hydrolysis of the corresponding alkyl esters having 1 to 6 carbon atoms in the alkyl moiety, in or without a water-miscible organic solvent, in the presence of a phase transfer catalyst. The hydrolysis is carried out with a 2 to 50% by weight aqueous alkali hydroxide solution. If desired, under suitable conditions the cis/trans ratio of the original ester can be altered in the end products. The cyclopropanecarboxylic acids of the formula (I) are obtained in a high purity and are useful intermediates of insecticidally active pyrethroids.
- -
-
-
- Resolution of D,L-cis and D,L-trans 2,2-dimethyl-3-(2,2-dihalovinyl)-cyclopropane-1-carboxylic acids and salts thereof
-
A novel process for the resolution of D,L-cis and D,L-trans 2,2-dimethyl-3-(2,2 -dihalovinyl)-cyclopropane-1-carboxylic acids of the formula STR1 wherein X is selected from the group consisting of fluorine, chlorine and bromine comprising salifying the said acid with an optically active base selected from the group consisting of D-ephedrine, L-ephedrine, D-N-methyl-ephedrine, L-N-methylephedrine, D-pseudo-ephedrine and L-pseudo-ephedrine to form the corresponding salt, recovering the said salt and subjecting the latter to acid hydrolysis to obtain the corresponding resolved acid which are intermediates for the synthesis of esters having a remarkable insecticidal activity.
- -
-
-
- Optically active isomers of substituted pyridine methyl esters of cyclopropane carboxylic acid and their use as insecticides
-
Optionally active isomers of substituted pyridine methyl esters of cyclopropane carboxylic acids thereof are prepared and have been found to exhibit a higher degree of insecticidal activity than their unresolved parents and compositions containing said compounds are so employed as insecticides.
- -
-
-
- Process for preparing cis-3-(2,2-dihalovinyl)-2,2-dimethylcyclopropanecarboxylic acid
-
Lactones of the formula STR1 wherein R is hydrogen or a CX3 group, and each X is a chlorine or bromine atom, are converted to the known cis-3-(2,2-dihalovinyl)-2,2-dimethylcyclopropanecarboxylic acids or lower alkyl esters, from which pyrethroid insecticides are obtained.
- -
-
-
- Ester synthesis
-
A novel process is described for the preparation of compounds of formula STR1 wherein R2 and R3 are each chloro or bromo; X is carboxyl, nitrile, optionally substituted carbonamide, carbonyl halide or an ester group. Those compounds wherein X is an appropriate ester group --COOB where B is an aryl group such as m-phenoxybenzyl are known insecticides; compounds where X is other than --COOB may be suitably converted thereto. The novel process consists of a series of steps from the corresponding acetyl compound of formula STR2 which comprises halogenation, reduction, esterification and finally elimination reactions.
- -
-
-
- Pyrethroid Photochemistry: Mechanistic Aspects in Reactions of the (Dihalogenovinyl)cyclopropanecarboxylate Substituent
-
The reaction quantum yields of six pyrethroid insecticides in methanol at 300 nm vary 3-10-fold between compounds with a cyclopentanone chromophore (allethrin) as compared with the phenoxybenzyl group (e.g., permethrin, decamethrin)in the alcohol moiety.Chlorine confers greater photostability than bromine in pyrethroids with dihalogenovinyl substituents in the acid moiety.Pathways for photodecomposition of methyl -2,2-dimethyl-3-(2,2-dibromovinyl)cyclopropanecarboxylate in methanol at 250 or 300 nm involve cis-trans isomerization, reductive debromination, and conversion of the dibromovinyl group into a bromomethoxy-epoxide derivative.Isomerization, but not debromination, involves a triplet excited state.
- Ruzo, Luis O.,Casida, John E.
-
p. 728 - 732
(2007/10/02)
-
- Process for the preparation of 2-(2',2',2'-trihalogenoethyl)-4-halogenocyclobutan-1-ones
-
A process for the preparation of 2-(2',2',2',-trihalogenoethyl)-4-halogenocyclobutan-1-ones of the formula STR1 in which one of the radicals R1 and R2 is methyl and the other is hydrogen or methyl, or R1 and R2 together are an alkylene group having 2 to 4 carbon atoms, and X and Y are each chlorine or bromine, comprising reacting a 2,4,4,4-tetrahalogenobutyric acid chloride in the presence of an organic base with an ethylene compound which is disubstituted in 1-position by the radicals R1 and R2, as defined above, to form a 2-(2',2',2'-trihalogenoethyl)-2-halogenocyclobutan-1-one and then rearranging the latter, in the presence of a catalyst, into a 2-(2',2',2'-trihalogenoethyl)-4-halogenocyclobutan-1-one of the above formula; said 2-(2',2',2'-trihalogenoethyl)-4-halogenocyclobutan-1-ones being valuable intermediates for the preparation of 2-(2',2'-dihalogenovinyl)-cyclopropanecarboxylic acid and its insecticidally active esters; as well as the 2-(2',2',2'-trihalogenoethyl)-4-halogenocyclobutan-1-ones of the above formula and the intermediates utilized for their preparation.
- -
-
-
- Process for converting 2,2-dichlorovinylcyclopropanes to dibromovinyl analogs
-
Treatment of 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acids and esters with aluminum bromide, the reaction product of aluminum and a bromoalkane, or HBr and the product of the reaction of HBr with aluminum or an aluminum salt produces the 3-(2,2-dibromovinyl)-2,2-dimethylcyclopropane analogs.
- -
-
-
- Lactones of 2,2-dimethyl-cyclopropane-1-carboxylic acids
-
Novel lactones of 2,2-dimethyl-cyclopropane-1-carboxylic acids of the formula STR1 wherein X1, X2 and X3 when identical are selected from the group consisting of chlorine and bromine and when at least two are different, are selected from the group consisting of fluorine, chlorine and bromine and a novel process for their preparation and a process for the preparation of cis 2,2-dimethyl-cyclopropane-1-carboxylic acids of the formula STR2
- -
-
-
- Insecticides
-
New insecticides are of formula: STR1 wherein R1 represents hydrogen or a methyl group; R2 represents hydrogen or a halogeno or lower alkyl group; R3 represents hydrogen or a halogeno, lower alkyl (which is different to R2 when R2 represents a lower alkyl group) or carbo(loweralkoxy) group which contains at least 2 carbon atoms in the lower alkoxy residue when R2 represents methyl or R2 and R3 together with the carbon atom to which they are attached represent a cycloalkylene ring having at least one endocyclic carbon to carbon double bond; with the proviso that (a) R2 and R3 each represent hydrogen only when R1 represents methyl and (b) R3 contains at least 2 carbon atoms when R1 and R2 each represent hydrogen; and R represents a group which form insecticidal esters with chrysanthemic acid e.g. 5-benzyl-3-furylmethyl, 3-phenoxybenzyl, α-cyano-3-phenoxybenzyl. The esters are prepared by forming the ester linkage conventionally or by a Wittig reaction using a 3-formyl- or 3-acetyl-2,2-dimethyl cyclopropane carboxylic acid esterified with the desired residue or by an alkyl group which is subsequently converted to the desired residue.
- -
-
-
