121-29-9

Basic information

• Product Name: PYRETHRIN 2
• Synonyms: (+)-pyrethronyl(+)-pyrethrate;2-methyl-4-oxo-3-(2,4-pentadienyl)-2-cyclopenten-1-yl3-(3-methoxy-2-methyl-3-o;2-methyl-4-oxo-3-(2,4-pentadienyl)-2-cyclopenten-1-ylester;2-methyl-4-oxo-3-(penta-2,4-dienyl)cyclopent-2-enyl3-(2-methoxycarbonylprop-1-enyl)-2,2-dimethylcyclopropanecarboxylate;3beta(e)))-*(z);3beta(e)]]-lpha[s(z);chrysanthemumdicarboxylicacidmonomethylesterpyrethroloneester;chrysanthemumdicarboxylicacidmonomethylesterpyrethroloneester.
• CAS NO: 121-29-9
• Molecular Formula: C₂₂H₂₈O₅
• Molecular Weight: 372.45472
• EINECS: 204-462-6
• Mol File: 121-29-9.mol
• Article Data: 1

Chemical Properties

• Boiling Point: bp0.007 192-193°
• Flash Point: 203.9 °C
• Appearance: /
• Density: 1.12 g/cm³
• Vapor Pressure: 3.84E-09mmHg at 25°C
• Refractive Index: nD20 1.5355
• CAS DataBase Reference: PYRETHRIN 2(CAS DataBase Reference)
• NIST Chemistry Reference: PYRETHRIN 2(121-29-9)
• EPA Substance Registry System: PYRETHRIN 2(121-29-9)

Safety Data

• Hazard Codes: Xn,N
• Statements: 20/21/22-50/53
• Safety Statements: 13-60-61
• RIDADR: 2902
• HazardClass: 6.1(b)
• PackingGroup: III
• Hazardous Substances Data: 121-29-9(Hazardous Substances Data)

Usage

Uses

Insecticide.

Indications

Pyrethrin (Licide, R&C, RID, Tisit) compounds and synthetic pyrethroids are used for the treatment of pediculosis. These are currently the drugs of choice in treating pediculosis. They demonstrate no scabicidal effect. Resistance has been shown to these compounds. They are absorbed through the chitinous exoskeleton and stimulate the nervous system, resulting in seizures and death of the insect.

Safety Profile

Poison experimentally by ingestion and intravenous routes. Moderately toxic to humans by unspecified route. An allergen. When heated to decomposition it emits acrid smoke and irritating fumes. An insecticide. See also other pyrethrin entries.

InChI:InChI=1/C22H28O5/c1-7-8-9-10-15-14(3)18(12-17(15)23)27-21(25)19-16(22(19,4)5)11-13(2)20(24)26-6/h7-9,11,16,18-19H,1,10,12H2,2-6H3/b9-8+,13-11+/t16-,18+,19+/m1/s1

Synthetic route

C21H26O5 + diazomethyl-trimethyl-silane (18107-18-1) → Pyrethrin II (121-29-9)

Conditions	Yield
With potassium carbonate In methanol; hexane; toluene at 20 - 25℃; for 16h; Inert atmosphere;	46%

(1R)-2.2-dimethyl-3t-<2-methoxycarbonyl-cis-propenyl>-cyclopropane-carboxylic acid-(1r)-chloride + (+)-cis-pyrethrolone → Pyrethrin II (121-29-9)

methyl (1R,3R)-3-formyl-2,2-dimethylcyclopropanecarboxylate (27335-33-7) → Pyrethrin II (121-29-9)

Conditions

Yield

Multi-step reaction with 5 steps 1.1: pyrrolidine / 1 h / 60 °C 2.1: potassium hydroxide / water; methanol; 5,5-dimethyl-1,3-cyclohexadiene / 16 h / 20 - 25 °C / Inert atmosphere 3.1: 1-methyl-1H-imidazole; p-toluenesulfonyl chloride; N-ethyl-N,N-diisopropylamine / acetonitrile / 0.5 h / 0 - 5 °C / Inert atmosphere 3.2: 2 h / 20 - 25 °C / Inert atmosphere 4.1: sodium dihydrogenphosphate; 2-methyl-but-2-ene; sodium chlorite / water; tert-butyl alcohol / 5 h / 20 - 25 °C 5.1: potassium carbonate / hexane; toluene; methanol / 16 h / 20 - 25 °C / Inert atmosphere View Scheme

(S)-(+)-4-hydroxy-3-methyl-2-(pent-4-en-2-ynyl)-2-cyclopenten-1-one → Pyrethrin II (121-29-9)

Conditions

Yield

Multi-step reaction with 4 steps 1.1: hydrogenchloride; zinc / ethanol; water / 16 h / 75 - 80 °C / Inert atmosphere 2.1: 1-methyl-1H-imidazole; p-toluenesulfonyl chloride; N-ethyl-N,N-diisopropylamine / acetonitrile / 0.5 h / 0 - 5 °C / Inert atmosphere 2.2: 2 h / 20 - 25 °C / Inert atmosphere 3.1: sodium dihydrogenphosphate; 2-methyl-but-2-ene; sodium chlorite / water; tert-butyl alcohol / 5 h / 20 - 25 °C 4.1: potassium carbonate / hexane; toluene; methanol / 16 h / 20 - 25 °C / Inert atmosphere View Scheme

(S)-(+)-pyrethrolone (487-67-2) → Pyrethrin II (121-29-9)

Conditions

Yield

Multi-step reaction with 3 steps 1.1: 1-methyl-1H-imidazole; p-toluenesulfonyl chloride; N-ethyl-N,N-diisopropylamine / acetonitrile / 0.5 h / 0 - 5 °C / Inert atmosphere 1.2: 2 h / 20 - 25 °C / Inert atmosphere 2.1: sodium dihydrogenphosphate; 2-methyl-but-2-ene; sodium chlorite / water; tert-butyl alcohol / 5 h / 20 - 25 °C 3.1: potassium carbonate / hexane; toluene; methanol / 16 h / 20 - 25 °C / Inert atmosphere View Scheme

ethyl trans-(+/-)-chrysanthemate (97-41-6, 1802-02-4, 7377-84-6, 15543-65-4, 16642-27-6, 34909-55-2, 41641-25-2, 41641-26-3, 41641-27-4) → Pyrethrin II (121-29-9)

Conditions

Yield

Multi-step reaction with 8 steps 1.1: potassium hydroxide / ethanol; water / 3 h 2.1: (S)-1-(1-Naphthyl)ethylamine / ethanol / 3 h / 20 °C 3.1: ozone / Acidic conditions 4.1: pyrrolidine / 1 h / 60 °C 5.1: potassium hydroxide / water; methanol; 5,5-dimethyl-1,3-cyclohexadiene / 16 h / 20 - 25 °C / Inert atmosphere 6.1: 1-methyl-1H-imidazole; p-toluenesulfonyl chloride; N-ethyl-N,N-diisopropylamine / acetonitrile / 0.5 h / 0 - 5 °C / Inert atmosphere 6.2: 2 h / 20 - 25 °C / Inert atmosphere 7.1: sodium dihydrogenphosphate; 2-methyl-but-2-ene; sodium chlorite / water; tert-butyl alcohol / 5 h / 20 - 25 °C 8.1: potassium carbonate / hexane; toluene; methanol / 16 h / 20 - 25 °C / Inert atmosphere View Scheme

trans-chrysanthemic acid (827-90-7, 2259-14-5, 2935-23-1, 4638-92-0, 10453-89-1, 15259-78-6, 26771-06-2, 26771-11-9, 705-16-8) → Pyrethrin II (121-29-9)

Conditions

Yield

Multi-step reaction with 7 steps 1.1: (S)-1-(1-Naphthyl)ethylamine / ethanol / 3 h / 20 °C 2.1: ozone / Acidic conditions 3.1: pyrrolidine / 1 h / 60 °C 4.1: potassium hydroxide / water; methanol; 5,5-dimethyl-1,3-cyclohexadiene / 16 h / 20 - 25 °C / Inert atmosphere 5.1: 1-methyl-1H-imidazole; p-toluenesulfonyl chloride; N-ethyl-N,N-diisopropylamine / acetonitrile / 0.5 h / 0 - 5 °C / Inert atmosphere 5.2: 2 h / 20 - 25 °C / Inert atmosphere 6.1: sodium dihydrogenphosphate; 2-methyl-but-2-ene; sodium chlorite / water; tert-butyl alcohol / 5 h / 20 - 25 °C 7.1: potassium carbonate / hexane; toluene; methanol / 16 h / 20 - 25 °C / Inert atmosphere View Scheme

(1R,3R)-trans-chrysanthemic acid (4638-92-0) → Pyrethrin II (121-29-9)

Conditions

Yield

Multi-step reaction with 6 steps 1.1: ozone / Acidic conditions 2.1: pyrrolidine / 1 h / 60 °C 3.1: potassium hydroxide / water; methanol; 5,5-dimethyl-1,3-cyclohexadiene / 16 h / 20 - 25 °C / Inert atmosphere 4.1: 1-methyl-1H-imidazole; p-toluenesulfonyl chloride; N-ethyl-N,N-diisopropylamine / acetonitrile / 0.5 h / 0 - 5 °C / Inert atmosphere 4.2: 2 h / 20 - 25 °C / Inert atmosphere 5.1: sodium dihydrogenphosphate; 2-methyl-but-2-ene; sodium chlorite / water; tert-butyl alcohol / 5 h / 20 - 25 °C 6.1: potassium carbonate / hexane; toluene; methanol / 16 h / 20 - 25 °C / Inert atmosphere View Scheme

(S)-4-hydroxy-3-methyl-2-(2-propynyl)-cyclopent-2-ene-1-one (77087-34-4) → Pyrethrin II (121-29-9)

Conditions

Yield

Multi-step reaction with 5 steps 1.1: copper(l) iodide; tetrakis(triphenylphosphine) palladium(0); triethylamine / toluene / 16 h / 20 - 25 °C / Inert atmosphere 2.1: hydrogenchloride; zinc / ethanol; water / 16 h / 75 - 80 °C / Inert atmosphere 3.1: 1-methyl-1H-imidazole; p-toluenesulfonyl chloride; N-ethyl-N,N-diisopropylamine / acetonitrile / 0.5 h / 0 - 5 °C / Inert atmosphere 3.2: 2 h / 20 - 25 °C / Inert atmosphere 4.1: sodium dihydrogenphosphate; 2-methyl-but-2-ene; sodium chlorite / water; tert-butyl alcohol / 5 h / 20 - 25 °C 5.1: potassium carbonate / hexane; toluene; methanol / 16 h / 20 - 25 °C / Inert atmosphere View Scheme

methyl (1R)-trans-2,2-dimethyl-3-[(E)-2-methyl-3-oxo-1-propenyl]cyclopropanecarboxylate (35867-05-1) → Pyrethrin II (121-29-9)

Conditions

Yield

Multi-step reaction with 4 steps 1.1: potassium hydroxide / water; methanol; 5,5-dimethyl-1,3-cyclohexadiene / 16 h / 20 - 25 °C / Inert atmosphere 2.1: 1-methyl-1H-imidazole; p-toluenesulfonyl chloride; N-ethyl-N,N-diisopropylamine / acetonitrile / 0.5 h / 0 - 5 °C / Inert atmosphere 2.2: 2 h / 20 - 25 °C / Inert atmosphere 3.1: sodium dihydrogenphosphate; 2-methyl-but-2-ene; sodium chlorite / water; tert-butyl alcohol / 5 h / 20 - 25 °C 4.1: potassium carbonate / hexane; toluene; methanol / 16 h / 20 - 25 °C / Inert atmosphere View Scheme

(1R,3R)-2,2-Dimethyl-3-((E)-2-methyl-3-oxoprop-1-en-1-yl)cyclopropane-1-carboxylic Acid → Pyrethrin II (121-29-9)

Conditions

Yield

Multi-step reaction with 3 steps 1.1: 1-methyl-1H-imidazole; p-toluenesulfonyl chloride; N-ethyl-N,N-diisopropylamine / acetonitrile / 0.5 h / 0 - 5 °C / Inert atmosphere 1.2: 2 h / 20 - 25 °C / Inert atmosphere 2.1: sodium dihydrogenphosphate; 2-methyl-but-2-ene; sodium chlorite / water; tert-butyl alcohol / 5 h / 20 - 25 °C 3.1: potassium carbonate / hexane; toluene; methanol / 16 h / 20 - 25 °C / Inert atmosphere View Scheme

C21H26O4 → Pyrethrin II (121-29-9)

Conditions	Yield
Multi-step reaction with 2 steps 1: sodium dihydrogenphosphate; 2-methyl-but-2-ene; sodium chlorite / water; tert-butyl alcohol / 5 h / 20 - 25 °C 2: potassium carbonate / hexane; toluene; methanol / 16 h / 20 - 25 °C / Inert atmosphere View Scheme

ethyl 2,2-dimethyl-3-(2-methylpropenyl)cyclopropanecarboxylate (97-41-6) → Pyrethrin II (121-29-9)

Conditions

Yield

Multi-step reaction with 9 steps 1.1: sodium hydride / mineral oil / 3 h / Inert atmosphere 2.1: potassium hydroxide / ethanol; water / 3 h 3.1: (S)-1-(1-Naphthyl)ethylamine / ethanol / 3 h / 20 °C 4.1: ozone / Acidic conditions 5.1: pyrrolidine / 1 h / 60 °C 6.1: potassium hydroxide / water; methanol; 5,5-dimethyl-1,3-cyclohexadiene / 16 h / 20 - 25 °C / Inert atmosphere 7.1: 1-methyl-1H-imidazole; p-toluenesulfonyl chloride; N-ethyl-N,N-diisopropylamine / acetonitrile / 0.5 h / 0 - 5 °C / Inert atmosphere 7.2: 2 h / 20 - 25 °C / Inert atmosphere 8.1: sodium dihydrogenphosphate; 2-methyl-but-2-ene; sodium chlorite / water; tert-butyl alcohol / 5 h / 20 - 25 °C 9.1: potassium carbonate / hexane; toluene; methanol / 16 h / 20 - 25 °C / Inert atmosphere View Scheme

Pyrethrin II (121-29-9) → (1S)-2-methyl-4-oxo-3-pentylcyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-en-1-yl)-2,2-dimethylcyclopropane-1-carboxylate

Conditions	Yield
With palladium 10% on activated carbon; hydrogen In tetrahydrofuran at 20℃; for 4h;	97%

Pyrethrin II (121-29-9) → (1S,4R)-4-hydroxy-2-methyl-3-((2Z)-penta-2,4-dien-1-yl)cyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-enyl)-2,2-dimethylcyclopropane-1-carboxylate

Conditions	Yield
With L-Selectride In tetrahydrofuran at 0℃; for 1h; Inert atmosphere; stereoselective reaction;	20%

Pyrethrin II (121-29-9) → 8',9'-epoxypyrethrin II + 10',11'-epoxypyrethrin II

Conditions	Yield
With 3-chloro-benzenecarboperoxoic acid In dichloromethane for 1.5h;	A 19% B 7%

Pyrethrin II (121-29-9) → (S)-2-methyl-4-oxo-3-(penta-1,3-dien-1-yl)cyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-en-1-yl)-2,2-dimethylcyclopropane-1-carboxylate + (1S)-2-methyl-4-oxo-3-((E)-penta-2,4-dien-1-yl)cyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-en-1-yl)-2,2-dimethylcyclopropane-1-carboxylate

Conditions	Yield
With formic acid; palladium 10% on activated carbon In tetrahydrofuran for 5h; Inert atmosphere; Reflux;	A 19% B 14%

Pyrethrin II (121-29-9) + acetic acid (64-19-7) → (1S,4R)-4-acetoxy-2-methyl-3-((2Z)-penta-2,4-dien-1-yl)cyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-enyl)-2,2-dimethylcyclopropane-1-carboxylate + (1S,4S)-4-acetoxy-2-methyl-3-((2Z)-penta-2,4-dien-1-yl)cyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-enyl)-2,2-dimethylcyclopropane-1-carboxylate + (1S,4R)-4-hydroxy-2-methyl-3-((2Z)-penta-2,4-dien-1-yl)cyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-enyl)-2,2-dimethylcyclopropane-1-carboxylate

Conditions	Yield
Stage #1: Pyrethrin II With 9-bora-bicyclo[3.3.1]nonane In tetrahydrofuran for 5h; Inert atmosphere; Stage #2: acetic acid In tetrahydrofuran for 1h; Inert atmosphere; Reflux;	A n/a B n/a C 19%

Pyrethrin II (121-29-9) → (-) trans-chrysanthemum dicarboxylic acid (72120-98-0)

Conditions	Yield
With potassium hydroxide In ethanol Hydrolysis;

Pyrethrin II (121-29-9) → 7',8'-epoxypyrethrin II + 7',8'-dihyroxypyrethrin II

Conditions	Yield
With 2,2'-azobis(isobutyronitrile) In benzene at 64℃; for 24h;	A n/a B 14 mg

Pyrethrin II (121-29-9) → 8',9'-dihydroxypyrethrin II

Conditions	Yield
Multi-step reaction with 2 steps 1: 3-chloro-benzenecarboperoxoic acid / dichloromethane / 1.5 h 2: water; sulfuric acid / methanol / 1 h / 20 °C View Scheme

Pyrethrin II (121-29-9) → (1S,4S)-4-hydroxy-2-methyl-3-((2Z)-penta-2,4-dien-1-yl)cyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-enyl)-2,2-dimethylcyclopropane-1-carboxylate + (1S,4R)-4-hydroxy-2-methyl-3-((2Z)-penta-2,4-dien-1-yl)cyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-enyl)-2,2-dimethylcyclopropane-1-carboxylate

Conditions	Yield
With sodium tetrahydroborate In tetrahydrofuran; methanol at 0℃; for 3h;	A 40 mg B 163 mg

Pyrethrin II (121-29-9) → (1S,4R)-4-acetoxy-2-methyl-3-((2Z)-penta-2,4-dien-1-yl)cyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-enyl)-2,2-dimethylcyclopropane-1-carboxylate

Conditions	Yield
Multi-step reaction with 2 steps 1.1: 9-bora-bicyclo[3.3.1]nonane / tetrahydrofuran / 5 h / Inert atmosphere 1.2: 1 h / Inert atmosphere; Reflux 2.1: triethylamine / dichloromethane / 4.5 h / Inert atmosphere; Reflux View Scheme
Multi-step reaction with 2 steps 1: L-Selectride / tetrahydrofuran / 1 h / 0 °C / Inert atmosphere 2: triethylamine / dichloromethane / 4.5 h / Inert atmosphere; Reflux View Scheme
Multi-step reaction with 2 steps 1: sodium tetrahydroborate / tetrahydrofuran; methanol / 3 h / 0 °C 2: triethylamine / dichloromethane / 4.5 h / Inert atmosphere; Reflux View Scheme

Pyrethrin II (121-29-9) → (1S,4S)-4-acetoxy-2-methyl-3-((2Z)-penta-2,4-dien-1-yl)cyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-enyl)-2,2-dimethylcyclopropane-1-carboxylate

Conditions	Yield
Multi-step reaction with 2 steps 1: sodium tetrahydroborate / tetrahydrofuran; methanol / 3 h / 0 °C 2: triethylamine / dichloromethane / 4.5 h / Inert atmosphere; Reflux View Scheme

Pyrethrin II (121-29-9) → (S)-2-methyl-4-oxo-3-((Z)-pent-2-en-1-yl)cyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-en-1-yl)-2,2-dimethylcyclopropane-1-carboxylate (1172-63-0) + (1S)-2-methyl-4-oxo-3-pentylcyclopent-2-en-1-yl (1R,3R)-3-((E)-3-methoxy-2-methyl-3-oxoprop-1-en-1-yl)-2,2-dimethylcyclopropane-1-carboxylate

Conditions	Yield
With copper(ll) sulfate pentahydrate; hydrazine hydrate; acetic acid In tetrahydrofuran	A 66 %Chromat. B 26 %Chromat.

Upstream product

• 188745-17-7 3-(3-chlorocarbonyl-2,2-dimethyl-cyclopropyl)-2-methyl-acrylic acid methyl ester 
• 18107-18-1 diazomethyl-trimethyl-silane 
• 97-41-6 ethyl 2,2-dimethyl-3-(2-methylpropenyl)cyclopropanecarboxylate 
• 93132-69-5 (1R,3R)-2,2-Dimethyl-3-((E)-2-methyl-3-oxoprop-1-en-1-yl)cyclopropane-1-carboxylic Acid 
• 35867-05-1 methyl (1R)-trans-2,2-dimethyl-3-[(E)-2-methyl-3-oxo-1-propenyl]cyclopropanecarboxylate 
• 77087-34-4 (S)-4-hydroxy-3-methyl-2-(2-propynyl)-cyclopent-2-ene-1-one 
• 4638-92-0 (1R,3R)-trans-chrysanthemic acid 
• 827-90-7 trans-chrysanthemic acid 
• 97-41-6 ethyl trans-(+/-)-chrysanthemate 
• 487-67-2 (S)-(+)-pyrethrolone 
• 27335-33-7 methyl (1R,3R)-3-formyl-2,2-dimethylcyclopropanecarboxylate 

Downstream Products

• 1172-63-0 jasmolin II 
• 131486-45-8 8',9'-dihydroxypyrethrin II 
• 131380-56-8 8',9'-epoxypyrethrin II 
• 131484-61-2 10',11'-epoxypyrethrin II 

Relevant articles and documents

Total Syntheses of All Six Chiral Natural Pyrethrins: Accurate Determination of the Physical Properties, Their Insecticidal Activities, and Evaluation of Synthetic Methods

Chiral total syntheses of all six insecticidal natural pyrethrins (three pyrethrin I and three pyrethrin II compounds) contained in the chrysanthemum (pyrethrum) flower were performed. Three common alcohol components [(S)-cinerolone, (S)-jasmololone, and (S)-pyrethrolone] were synthesized: (i) straightforward Sonogashira-type cross-couplings using available (S)-4-hydroxy-3-methyl-2-(2-propynyl)cyclopent-2-en-1-ones (the prallethrin alcohol) for (S)-cinerolone (overall 52% yield, 98% ee) and (S)-pyrethrolone (overall 54% yield, 98% ee) and (ii) traditional decarboxylative-aldol condensation and lipase-catalyzed optical resolution for (S)-jasmololone (overall 16% yield, 96% ee). Two counter acid segments [(1R,3R)-chrysanthemic acid (A) and (1R,3R)-second chrysanthemic acid precursor (B)] were prepared: (i) C(1) epimerization of ethyl (±)-chrysanthemates and optical resolution using (S)-naphthylethylamine to afford A (96% ee) and (ii) concise derivatization of A to B (96% ee). All six pyrethrin esters (cinerin I/II, jasmolin I/II, and pyrethrin I/II) were successfully synthesized utilizing an accessible esterification reagent (TsCl/N-methylimidazole). To investigate the stereostructure-activity relationship, all four chiral stereoisomers of cinerin I were synthesized. Three alternative syntheses of (±)-jasmololone were investigated (methods utilizing Piancatelli rearrangement, furan transformation, and 1-nitropropene transformation). Insecticidal activity assay (KD50 and IC50) against the common mosquito (Culex pipiens pallens) revealed that (i) pyrethrin I > pyrethrin II, (ii) pyrethrin I (II) > cinerin I (II) ? jasmolin I (II), and (iii) "natural" cinerin I ? three "unnatural" cinerin I compounds (apparent chiral discrimination).