- Novel synthesis method for methyl dichlorochrysanthemate
-
The invention provides a synthesis method for methyl dichlorochrysanthemate. The process comprises the following steps: putting an amine catalyst into 3,3-dimethyl-4,6,6,6-tetrachloromethyl n-hexanoate with stirring, so as to obtain a raw material mixture; heating the obtained raw material mixture to the temperature of 20-60 DEG C, dropwise adding a liquid organic base into the raw material mixture, and enabling the mole ratio of the organic base to 3,3-dimethyl-4,6,6,6-tetrachloromethyl n-hexanoate to reach (2.0-2.5): 1; and after the dropwise adding is completed, carrying out heat preservation on the reaction mixture for 0.5-3.0 hours at the temperature of 20-60 DEG C, stopping reaction when the content of 3,3-dimethyl-4,6,6,6-tetrachloromethyl n-hexanoate is lower than 0.3%, and subjecting a product to subsequent treatment, thereby obtaining methyl dichlorochrysanthemate. According to the method provided by the invention, solvents required for the synthesis of methyl dichlorochrysanthemate are canceled, the consumption of the organic base is lowered, the reaction temperature is lowered, the reaction time is shortened, and the production of impurities such as alkyne esters is reduced while the reaction is full, so that the quality of methyl dichlorochrysanthemate is obviously improved. The method is simple in process and convenient in operation and is very beneficial to industrialization.
- -
-
Paragraph 0026; 0027
(2017/03/08)
-
- New catalytic system Cu(OAc)2-2,4-lutidine-ZnCl2 for olefin cyclopropanation with methyl diazoacetate
-
A new efficient catalytic system consisting of Cu(OAc)2, 2,4-lutidine, and ZnCl2 was found for the cyclopropanation of unsaturated compounds with methyl diazoacetate. In the case of conjugated dienes, the process occurs regioselectively at the most alkylated C=C bond.
- Gareev,Sultanova,Biglova,Dokichev,Tomilov
-
experimental part
p. 1784 - 1786
(2011/04/23)
-
- An efficient and selective conversion of hydrazides into esters and acids
-
Hydrazides are selectively oxidised to esters/acids in high yields using Oxone in the presence of an appropriate alcohol/water as a nucleophile at ambient temperature. A variety of functional groups including alkenes, alcohols, ethers, cyclopropyl groups and nitriles are unaffected.
- Srinivas,Subba Reddy,Yadav,Ramalingam
-
p. 376 - 377
(2007/10/03)
-
- A stereoselective synthesis of methyl trans-3-(2,2-dichloroethenyl)- 2,2-dimethylcyclopropanecarboxylate
-
A convenient method is described for the stereoselective synthesis of methyl trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate (5) via methyl 3,3-dimethyl-4,6,6,6-tetrachlorohexanoate (4) as a key intermediate, which was obtained by addition of carbon tetrachloride to methyl 3,3-dimethyl-4-pentenoate (3). Treatment of (4) with sodium methoxide in a single-vessel via methyl 4,6,6-trichloro-3,3-dimethyl-5-hexenoate (6) gave trans-rich (5) in excellent yield.
- Ma, Jun'an,Huang, Runqiu,Cheng, Junran,Shao, Ruilian,Li, Zaiguo
-
p. 1653 - 1659
(2007/10/03)
-
- Search for Routes of Synthesis of Permethrin and Chloropermethrin Starting from Halogen-containing Alkenoic Acids
-
Promising procedures were developed for the synthesis of permethrin and I-chloropermethrin starting from acid chloride, nitrile, and esters of 3,3-dimethyl-2,2,4,6,6-pentachloro-5-alkenoic acid and 3,3-dimethyl-2,2,6,6-tetrachloro-5-alken-4-olide, which were prepared by adding derivatives of trichloroacetic acid to 1,1-dichloro-4-methyl-1,3-pentadiene in the presence of catalytic amounts of monovalent copper ions and amine.
- Badanyan,Stepanyan,Mikaelyan,Ovivyan,Panosyan
-
-
- Method for producing optically active cyclopropane carboxylic acid
-
The present relates to a process for preparing optically active cyclopropane carboxylic acid derivatives of salts thereof represented by the formula (III) STR1 wherein X is chlorine atom, bromine atom, methyl group or trifluoromethyl group and R' is hydrogen atom or metal ion, by asymmetrically hydrolyzing cyclopropane carboxylic acid esters having the formula (II) STR2 wherein X is as defined above and R is C1-4 alkyl group or halogen-substituted C1-4 alkyl group with specific strains of microorganisms or esterase derived therefrom.
- -
-
-
- Process for production of β-dihalogenoethenylcyclopropane derivatives
-
A novel process for producing a β-dihalogenoethenylcyclopropane derivative of the formula, STR1 wherein R1 is a hydrogen atom or an alkyl group, R3 is a hydrogen atom, lower alkyl, acyl, carboxyl or alkoxycarbonyl group and R is a hydrogen atom or a lower alkyl group and each of Y1 and Y2 is a fluorine, chlorine or bromine atom respectively, which is an acidic moiety of the useful synthetic insecticides of the pyrethrin type, which process comprises a combination of a series of sequential steps starting from alkyl 3-butenyl ketone derivative of the formula (I), which may be shown according to the following reaction scheme: STR2 According to this process, objective compound of the formula (VI) having any cis/trans ratio can be produced by selecting the reaction condition of the Stages II-1, II-2, and IV-2.
- -
-
-
- Process for the preparation of vinylcyclopropanecarboxylic acid derivatives
-
Disclosed is a process for preparing cis-trans isomer mixtures of 2,2-dimethyl-3(β,β-dichlorovinyl)-cyclopropane-1-carboxylic acid esters, having a high cis/trans isomer ratio, wherein a 4,4-dimethyl-5-halogen-6-alkoxytetrahydro-pyrone or a 3,3-dimethyl-4-halogen-5-oxo-pentanic acid ester is reacted with dichlorophosphonic acid esters in the presence of alkali alcoholates or alkali hydrides or lithium alkyls. Also disclosed are novel starting tetrahydropyrone compounds usable in the above process, and a process for preparation of the novel compounds which includes reacting β,β-dimethyl-γ,δ-dihalogen-δ-valerolactones with alkali alcoholates at reaction temperatures between -10° and +50° C.
- -
-
-
- Method of producing cyclopropanecarboxylic acids and esters
-
Novel γ-lactone derivatives are provided. These lactone derivatives, when reacted with hydrogen halide in alcohol, yield γ-halogeno-δ-unsaturated carboxylic acid esters. This ring-opening process is useful for the purpose of increasing the yield of pyrethrin analogs which are of value as insecticides and agricultural chemicals. Thus, the γ-lactone derivatives by-produced in the production process for dihalogenovinyl chrysanthemumates are caused to undergo ring-opening reaction to yield the corresponding γ-halogeno-δ-unsaturated carboxylic acid esters which are important intermediates for said pyrethrin analogs.
- -
-
-
- TRANSITION-METAL-CATALYSED REACTIONS OF DIAZOESTERS : SYNTHESIS OF CHRYSANTHEMIC AND PERMETHRIC ACID ESTERS BY CYCLOPROPANATION OF CONJUGATED DIENES
-
Pyrethroid precursors (permethric and chrysanthemic acid esters) are efficiently synthesized by rhodium(II)-catalysed cyclopropanation of the properly substituted conjugated diene.Reaction selectivities depend on both the catalyst counter-ion and the diazoester alkoxy-group (carbene precursor) and are attributed to non-bonded interactions.
- Demonceau, A.,Noels, A. F.,Anciaux, A. J.,Hubert, A. J.,Teyssie, P.
-
p. 949 - 952
(2007/10/02)
-
- Process of preparing dihalovinyl compounds
-
Conversion of esters (R1)(R2)C(C Hal3)OX, X being-P Hal2, --C(O)OR3 or STR1 R1, R3 and R4 being optionally substituted hydrocarbyl groups and R2 methyl or hydrogen, with zinc in acetic acid gives a very high yield of a dihalovinyl compound (R1)(R2)C=C Hal2, e.g., of the ethyl ester of the parent acid of pyrethroid insecticides.
- -
-
-
- 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 preparing high cis 3-(2,2,2-trichloroethyl)-2,2-dimethylcyclopropane-1-carboxylates
-
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.
- -
-
-
- Process for preparation of substituted cyclopropane carboxylic acids and esters thereof and intermediates of said acids and esters
-
When 1-halogeno-3-alkene-2-ol is reacted with an ortho-carboxylic ester and/or a ketene acetal, a γ-halogeno-δ-unsaturated-carboxylic ester is obtained as a main reaction product. When this intermediate is treated with a basic substance, a substituted cyclopropane-carboxylic ester is formed. This ester can be used as an insecticide or an agricultural chemical as it is or after the alcohol residue of the ester has been converted to other alcohol residue.
- -
-
-