65731-84-2

Basic information

• Product Name: BETA-CYPERMETHRIN
• Synonyms: ASYMETHRIN;(1R)-2,2-Dimethyl-3β-(2,2-dichlorovinyl)cyclopropane-1β-carboxylic acid (S)-α-cyano-3-phenoxybenzyl ester;(1R)-3β-(2,2-Dichloroethenyl)-2,2-dimethylcyclopropane-1β-carboxylic acid (S)-α-cyano-3-phenoxybenzyl ester;(1R,3R)-3-(2,2-Dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid (S)-α-cyano-3-phenoxybenzyl ester;(1R,3R)-3-(2,2-Dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid (αS)-α-cyano-3-phenoxybenzyl ester;(1R,αS)-cis-Cypermethrin;(1R-cis-αS)-Cypermethrin;NRDC-168S
• CAS NO: 65731-84-2
• Molecular Formula: C₂₂H₁₉Cl₂NO₃
• Molecular Weight: 416.3
• EINECS: 265-898-0
• Mol File: 65731-84-2.mol

Chemical Properties

• Melting Point: 53-55 °C
• Boiling Point: 511.3 °C at 760 mmHg
• Flash Point: 263 °C
• Appearance: /
• Density: 1.329 g/cm³
• Vapor Pressure: 2.03E-27mmHg at 25°C
• Water Solubility: 0.09 mg l-1(25 °C)
• CAS DataBase Reference: BETA-CYPERMETHRIN(CAS DataBase Reference)
• NIST Chemistry Reference: BETA-CYPERMETHRIN(65731-84-2)
• EPA Substance Registry System: BETA-CYPERMETHRIN(65731-84-2)

Safety Data

• Hazardous Substances Data: 65731-84-2(Hazardous Substances Data)

Usage

Uses

Used in Agriculture:
BETA-CYPERMETHRIN is used as an insecticide for controlling a wide range of insects, particularly Lepidoptera (moths and butterflies) and Coleoptera (beetles), in various crops. These crops include alfalfa, cotton, cereals, fruit, vines, vegetables, beans, beets, tobacco, and oilseed rape. Its effectiveness in controlling pests helps to protect the yield and quality of these crops.
Used in Public Health:
BETA-CYPERMETHRIN is also used for insect control in public health, targeting insects that transmit diseases or cause discomfort to humans. Its use in this context helps to reduce the spread of illnesses and improve overall public health.
Used in Ectoparasite Control on Animals:
In addition to its applications in agriculture and public health, BETA-CYPERMETHRIN is used for controlling ectoparasites on animals. This helps to protect livestock and pets from the harmful effects of parasites, such as skin irritation, blood loss, and the transmission of diseases.

Metabolic pathway

Beta-cypermethrin is composed of two of the four cis-cypermethrin isomers (1RcisaS and 1ScisaR isomers) [i.e. alpha-cypermethrin] and two of the four trans-cypermethrin isomers (1RtransaS and 1StransaR) [i.e. thetacypermethrin]. The fate of these four isomers (separately) has been reported for soils. Metabolite analysis was conducted in enough detail to indicate that the fate of the components was very similar to their fate when presented to biological systems as part of cypermethrin. Thus reference can be made to the cypermethrin entry for details. The structure and Scheme numbering used below refers to the cypermethrin entry.

Degradation

Beta-cypermethrin is stable as a solid but it is epimerised in weak base solution and readily hydrolysed at higher pH. Its half-lives at pH values 3, 7 and 9 (25 °C) were 50,40 and 15 days (PM). By analogy with cypermethrin, the rate-determining step in dilute solution is nucleophilic attack by OH-. Half-lives of cis-cypermethrin in river water and sea water at 25 °C were 21 and 24 days, respectively; the trans-isomer would be expected to be more rapidly degraded. Major products were 3-(2,2- dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid (2, DCVA), 3- phenoxybenzaldehyde (9, 3PBAl) and a-carbamoyl-3-phenoxybenzyl 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate( the amide 3); minor products were the a-carboxy analogue of 3 (4) and 3- phenoxybenzoic acid (10,3PBA) (see cypermethrin, Schemes la and lb). Photodecomposition would be expected to be similar to that of cypermethrin.

InChI:InChI=1/2C22H19Cl2NO3/c2*1-22(2)17(12-19(23)24)20(22)21(26)28-18(13-25)14-7-6-10-16(11-14)27-15-8-4-3-5-9-15/h2*3-12,17-18,20H,1-2H3/t2*17-,18-,20+/m10/s1

Upstream product

• 39515-47-4 2-hydroxy-2-(3-phenoxyphenyl)acetonitrile 
• 69831-14-7 (1R,3R)-(+)-3-(2,2-Dichlorvinyl)-2,2-dimethylcyclopropanecarboxylic acid chloride 
• 52315-07-8 cypermethrine 
• 65731-83-1 alpha-cypermethrin 
• 39515-51-0 3-Phenoxybenzaldehyde 
• 72812-59-0 (R)-1,1,1-Trichloro-4-methyl-3-penten-2-yl (S)-N-<1-(1-naphthyl)ethyl>carbamate 
• 72843-77-7 (1R,4R,5S)-(-)-6,6-Dimethyl-4-(trichloromethyl)-3-oxobicyclo<3.1.0>hexan-2-one 
• 73986-06-8 (R)-1,1,1-Trichloro-4-methyl-3-penten-2-yl diazoacetoacetate 
• 72800-50-1 (R)-1-trichloromethyl-3-methyl-2-butenyl acetoacetate 
• 72800-54-5 (R)-(+)-1,1,1-Trichloro-4-methyl-3-penten-2-yl diazoacetate 
• 73986-07-9 1,1,1-Trichloro-2-oxo-4-methyl-3-pentene 
• 72843-76-6 (R)-(-)-1,1,1-trichloro-2-hydroxy-4-methyl-3-pentene 
• 55667-40-8 1(R)-cis-permethrinic acid 
• 72800-48-7 1,1,1-trichloro-4-methyl-3-penten-2-ol 

Downstream Products

• 200798-95-4 4-{[2-[3-(2,2-Dichloro-vinyl)-2,2-dimethyl-cyclopropanecarbonyloxy]-2-(3-phenoxy-phenyl)-acetylamino]-methyl}-cyclohexanecarboxylic acid 2-trimethylsilanyl-ethyl ester 
• 200798-96-5 4-{[2-[3-(2,2-Dichloro-vinyl)-2,2-dimethyl-cyclopropanecarbonyloxy]-2-(3-phenoxy-phenyl)-acetylamino]-methyl}-cyclohexanecarboxylic acid 
• 200798-74-9 3-(2,2-Dibromo-vinyl)-2,2-dimethyl-cyclopropanecarboxylic acid (2-tert-butoxycarbonyl-ethylcarbamoyl)-(3-phenoxy-phenyl)-methyl ester 
• 200798-75-0 3-(2,2-Dichloro-vinyl)-2,2-dimethyl-cyclopropanecarboxylic acid (2-tert-butoxycarbonyl-ethylcarbamoyl)-(3-phenoxy-phenyl)-methyl ester 
• 200798-82-9 3-(2-tert-Butoxycarbonyl-ethylcarbamoyl)-2,2-dimethyl-cyclopropanecarboxylic acid cyano-(3-phenoxy-phenyl)-methyl ester 
• 200798-77-2 3-(2,2-Dibromo-vinyl)-2,2-dimethyl-cyclopropanecarboxylic acid (2-carboxy-ethylcarbamoyl)-(3-phenoxy-phenyl)-methyl ester 
• 200798-78-3 3-(2,2-Dichloro-vinyl)-2,2-dimethyl-cyclopropanecarboxylic acid (2-carboxy-ethylcarbamoyl)-(3-phenoxy-phenyl)-methyl ester 
• 200798-83-0 3-(2-Carboxy-ethylcarbamoyl)-2,2-dimethyl-cyclopropanecarboxylic acid cyano-(3-phenoxy-phenyl)-methyl ester 
• 200798-90-9 Succinic acid cyano-(3-phenoxy-phenyl)-methyl ester 2-trimethylsilanyl-ethyl ester 
• 200798-72-7 3-(2,2-Dibromo-vinyl)-2,2-dimethyl-cyclopropanecarboxylic acid carboxy-(3-phenoxy-phenyl)-methyl ester 
• 68749-35-9 3-(2,2-Dichloro-vinyl)-2,2-dimethyl-cyclopropanecarboxylic acid carboxy-(3-phenoxy-phenyl)-methyl ester 
• 92830-21-2 4-(cyano(3-phenoxyphenyl)methoxy)-4-oxobutanoic acid 

Relevant articles and documents

Stereoselective Degradation of alpha-Cypermethrin and Its Enantiomers in Rat Liver Microsomes

Alpha-cypermethrin (α-CP), [(RS)-a-cyano-3-phenoxy benzyl (1RS)-cis-3-(2, 2-dichlorovinyl)-2, 2-dimethylcyclopropanecarboxylate], comprises a diastereoisomer pair of cypermethrin, which are (+)-(1R-cis-αS)-CP (insecticidal) and (-)-(1S-cis-αR)-CP (inactive). In this experiment, the stereoselective degradation of α-CP was investigated in rat liver microsomes by high-performance liquid chromatography (HPLC) with a cellulose-tris- (3, 5-dimethylphenylcarbamate)-based chiral stationary phase. The results revealed that the degradation of (-)-(1S-cis-αR)-CP was much faster than (+)-(1R-cis-αS)-CP both in enantiomer monomers and rac-α-CP. As for the enzyme kinetic parameters, there were some variances between rac-α-CP and the enantiomer monomers. In rac-α-CP, the Vmax and CLint of (+)-(1R-cis-αS)-CP (5105.22 ± 326.26 nM/min/mg protein and 189.64 mL/min/mg protein) were about one-half of those of (-)-(1S-cis-αR)-CP (9308.57 ± 772.24 nM/min/mg protein and 352.19 mL/min/mg protein), while the Km of the two α-CP enantiomers were similar. However, in the enantiomer monomers of α-CP, the Vmax and Km of (+)-(1R-cis-αS) -CP were 2-fold and 5-fold of (-)-(1S-cis-αR)-CP, respectively, which showed a significant difference with rac-α-CP. The CLint of (+)-(1R-cis-αS)-CP (140.97 mL/min/mg protein) was still about one-half of (-)-(1S-cis-αR)-CP (325.72 mL/min/mg protein) in enantiomer monomers. The interaction of enantiomers of α-CP in rat liver microsomes was researched and the results showed that there were different interactions between the IC50 of (-)- to (+)-(1R-cis-αS)-CP and (+)- to (-)-(1S-cis-αR)-CP(IC50(-)/(+) / IC50(+)/(-) =0.61).

Epimerization of cypermethrin stereoisomers in alcohols

Isomerization induced by light, heat, and organic solvents has been shown to occur for some pyrethroid insecticides. Alcohols are popular solvents that are used in sample extraction, storage, and analysis. Thus, alcohol-induced epimerization may contribute to the incorrect interpretation of results from enantioselective chemical analysis and bioassay of pyrethroids like Cypermethrin. In this study, we investigated the relationship between the rate of epimerization of Cypermethrin stereoisomers: 1R-cis-αR and 1R-trans-αR and short-chain alkyl alcohol properties. In this study, complete epimerization of 1R-cis-αR produced an almost equal fraction of 1R-cis-αS, and that of 1R-trans-αR yielded 1R-trans-αS. For both stereoisomers, epimerization was most rapid in ethanol. The same stereoisomers underwent relatively rapid epimerization in methanol, n-propanol, 2-methyl1-propanol, and n-butanol but were stable in 2-butanol, suggesting that secondary alcohols have reduced reactivity, likely due to steric hindrance. We further evaluated epimerization of 1R-cis-αR and 1R-trans-αR stereoisomers of Cypermethrin as a function of water content in methanol. The presence of water in methanol generally increased the epimerization rate. For 1R-cis-αR, epimerization was most rapid with a water content of ≤2%, while for 1R-trans-αR, epimerization was most rapid with a water content of 10%. Results from this study clearly show that contact with commonly used primary alcohols may result in rapid abiotic epimerization, underscoring the importance of considering configurational stability in ensuring the analytical integrity and correct interpretation of bioassay data for stereoisomers of cypermethrin and similar pyrethroids. 2009 American Chemical Society.

Abiotic enantiomerization of permethrin and cypermethrin: Effects of organic solvents

All synthetic pyrethroids are chiral compounds, and isomerization has been frequently observed from exposure to certain solvents. However, so far, pyrethroid isomerization caused by solvents has not been characterized at the enantiomer level. In this study, we evaluated the occurrence of enantiomerization of two commonly used pyrethroids, permethrin and cypermethrin, in various organic solvents and solvent-water systems. The four stereoisomers of permethrin were stable under all test conditions. Rapid enantiomerization of cypermethrin was observed in isopropanol and methanol but not in n-hexane, acetone, or methylene chloride. After 4 days at room temperature, 18-39% conversions occurred for the different cypermethrin stereoisomers in isopropanol and methanol, and the enantiomerization invariably took place at the α-carbon position. The extent of enantiomerization was affected by temperature dependence and was also influenced by water as a cosolvent. In solvent-water mixtures, cypermethrin underwent gradual enantiomerization in acetone-water and rapid enantiomerization in isopropanol-water or methanol-water. The extent of enantiomerization varied among the solvents and as a function of the solvent-to-water ratio. Results from this study suggest that exposure to certain solvents and water may cause artifacts in chiral analysis and that for isomer-enriched pyrethroid products, such abiotic enantiomerization may render the products less effective because the conversion leads to the formation of inactive stereoisomers.

Synthesis of (1R,cis,αS)-cypermethrine via lipase catalyzed kinetic resolution of racemic m-phenoxybenzaldehyde cyanohydrin acetate

A technical scale preparation of optically active (1R,cis, αS)- cypermethrine 4 from racemic m-phenoxybenzaldehyde cyanohydrin acetate (RS)- 1 and (1R,cis)-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-carboxylic acid chloride (1R,cis)-3 is described. Key steps of the new procedure are a lipase catalyzed enantioselective transesterification of (RS)-1 with n-butanol and direct acylation of the mixture of (R)-1 and (S)-cyanohydrin (S)-2 with (1R,cis)-3 to give enantiomerically pure (1R,cis,αS)-4. The unchanged (R)-1 is removed from (1R,cis,αS)-4 by distillation, and is racemized with triethylamine to give (RS)-1 which is returned to the process. The total yield of (1R,cis,αS)-4 referred to (RS)-1 is 80%.

Stereospecific Total Synthesis of the Potent Synthetic Pyrethroid NRDC 182

A highly stereospecific synthesis of (1R,3R)-cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid was devised which allowed for a total synthesis of the potent synthetic pyrethroid insecticide (S)-cyano-(3-phenoxyphenyl)methyl (1R,3R)-cis-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropancarboxylate (NRDC 182).Asymmetric reduction of 1,1,1-trichloromesityl oxide with an LAH-ephedrine complex produced (2R)-1,1,1-trichloro-2-hydroxy-4-methylpent-3-ene which was transformed to a diazoacetate ester via the corresponding diazoacetoacetate.Copper-catalyzed thermal decomposition of the diazoacetate resulted in internal carbenoid cyclization onto the olefin in nearly quantitative stereoselectivity.The resultant bicyclic lactone was ring opened via a Boord-type reaction to give the requisite cyclopropane acid which was esterified with racemic 3-phenoxybenzaldehyde cyanohydrin followed by recrystallization and epimerization of the mother liquor to produce NRDC 182.