10453-89-1Relevant articles and documents
Unprecedented dual reactivity of anhydrous potassium hydroxide in cascade cyclopropannelation/Haller-Bauer-scission/Grob-fragmentation reactions
Krief, Alain,Kremer, Adrian
, p. 4306 - 4309 (2010)
We report an unprecedented type of reactivity of 'anhydrous potassium hydroxide' ('APH') in which it plays, over a large variety of related educts, sequentially the role of base and nucleophile. Some insight into the structure of reactive species as well as comparative reactivity of related reagents prepared by fusion of commercially available potassium hydroxide or by adding stoichiometric amount of water to potassium hydride is provided.
A New Photochemical Synthesis of Cyclopropanecarboxylic Acids Present in Pyrethroids by the Aza-di-?-methane Rearrangement
Armesto, Diego,Gallego, Mar G.,Horspool, William M.,Agarrabeitia, Antonia R.
, p. 9223 - 9240 (1995)
A novel synthetic route to chrysanthemic acid, 2-cyclopentylidenmethyl-3,3-dimethylcyclopropanecarboxylic acid, fluorenespiro-2,2-dimethylcyclopropanecarboxylic acid and indenespiro-2,2-dimethylcyclpropanecarboxylic acid, all of them present in pyrethroids of known insecticidal activity, is described.The key step in the synthesis is the aza-di-?-methane rearrangement of some 1-aza-1,4,6-trienes and some 1-aza-1,4-dienes, using triplet sensitization.
Lipase catalysed kinetic resolution of racemic (±)2,2-dimethyl-3-(2-methyl-1-propenyl)-cyclopropane carboxyl esters
Bhaskar Rao,Rehman,Krishnakumari,Yadav
, p. 2611 - 2614 (1994)
Optically active (1R)(-) and (1S)(+)-trans-Chrysanthemic acid and its esters were prepared from corresponding racemic methyl ester by lipase mediated enantioselective hydrolysis, is described.
Electron transfer photochemistry of chrysanthemol: An intramolecular S(N)2' reaction of a vinylcyclopropane radical cation
Herbertz, Torsten,Roth, Heinz D.
, p. 10954 - 10962 (1996)
The electron transfer photochemistry of optically pure (1R,3S)-(+)-cis-chrysanthemol (cis-2) results in the formation of (R)-5-(1-(p-cyanophenyl)-1-methylethyl)-2,2-dimethyl oxacyclohex-3-ene (4) with significant retention of optical activity. The product is rationalized via nucleophilic attack of the alcoholic function of the radical cation on the terminal carbon of the vinyl group with simultaneous replacement of an isopropyl radical as an intramolecular leaving group in an apparent S(N)2' reaction. This mode of attack is unprecedented in vinylcyclopropane radical cations and is interpreted as evidence for the significant role that relief of ring strain and its avoidance play in determining the course of nucleophilic capture in radical cationic systems.
Total Syntheses of All Six Chiral Natural Pyrethrins: Accurate Determination of the Physical Properties, Their Insecticidal Activities, and Evaluation of Synthetic Methods
Ashida, Yuichiro,Kawamoto, Momoyo,Matsuo, Noritada,Moriyama, Mizuki,Tanabe, Yoo
, p. 2984 - 2999 (2020/03/24)
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).
Cyclopropanation of Terminal Alkenes through Sequential Atom-Transfer Radical Addition/1,3-Elimination
Tappin, Nicholas D. C.,Michalska, Weronika,Rohrbach, Simon,Renaud, Philippe
supporting information, p. 14240 - 14244 (2019/08/26)
An operationally simple method to affect an atom-transfer radical addition of commercially available ICH2Bpin to terminal alkenes has been developed. The intermediate iodide can be transformed in a one-pot process into the corresponding cyclopropane upon treatment with a fluoride source. This method is highly selective for the cyclopropanation of unactivated terminal alkenes over non-terminal alkenes and electron-deficient alkenes. Due to the mildness of the procedure, a wide range of functional groups such as esters, amides, alcohols, ketones, and vinylic cyclopropanes are well tolerated.
Clean production method of pyrethroid intermediate chrysanthemic acid
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Paragraph 0042-0047, (2018/03/26)
The invention discloses a clean production method of a pyrethroid intermediate chrysanthemic acid. The clean production method comprises: mixing a Lewis acid and water to form an acid aqueous solution; pouring chrysanthemate and the acid aqueous solution into an acidolysis reaction kettle, heating the system, and carrying out a reflux reaction, wherein the upper layer oil layer in the acidolysis reaction kettle is crude chrysanthemic acid and the lower layer water layer is the acid aqueous solution after the reflux reaction is completed; and introducing the oil layer into a water washing kettle, adding water, carrying out water washing, and carrying out standing layering, wherein the upper layer is the water washing liquid, the lower layer oil layer is the finished product chrysanthemic acid, the finished product chrysanthemic acid is directly harvested, and the lower layer acid aqueous solution in the acidolysis reaction kettle and the upper layer water washing liquid in the water washing kettle can be recycled after the combination. According to the present invention, the used acid aqueous solution can be recycled and applied indefinitely, the hydrolysis is acidic hydrolysis anddoes not produce any high-salt wastewater, and the product chrysanthemic acid is the product with the purity of 99.5% without extraction and concentration.
Syntheses of racemic and scalemic cis-chrysanthemic acid from β,γ-unsaturated cyclohexanol
Krief, Alain,Jeanmart, Stéphane,Gondal, Humaira Y.,Kremer, Adrian
, p. 2123 - 2167 (2013/02/23)
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.
A practical method for O-acylation of N -hydroxythiazole-2(3 H)-thiones
Schur, Christine,Gross, Andreas,Hartung, Jens
experimental part, p. 538 - 542 (2010/06/13)
O-Acylation of 4- and 4,5-substituted N-hydroxythiazole-2(3H)-thiones occurred in solutions of acetone upon treatment with solid K2CO3 and a variety of neat acyl chlorides (primary, secondary, and tertiary alkyl, aryl; 60-87% yield; ～10 g scale).
Betulin-derived compounds as inhibitors of alphavirus replication
Pohjala, Leena,Alakurtti, Sami,Ahola, Tero,Yli-Kauhaluoma, Jari,Tammela, Paeivi
supporting information; experimental part, p. 1917 - 1926 (2010/04/29)
This paper describes inhibition of Semliki Forest virus (SFV) replication by synthetic derivatives of naturally occurring triterpenoid betulin (1). Chemical modifications were made to OH groups at C-3 and C-28 and to the C-20-C-29 double bond. A set of heterocyclic betulin derivatives was also assayed. A free or acetylated OH group at C-3 was identified as an important structural contributor for anti-SFV activity, 3,28-di-O-acetylbetulin (4) being the most potent derivative (IC50 value 9.1 μM). Betulinic acid (13), 28-O-tetrahydropyranylbetulin (17), and a triazolidine derivative (41) were also shown to inhibit Sindbis virus, with IC50 values of 0.5, 1.9, and 6.1 μM, respectively. The latter three compounds also had significant synergistic effects against SFV when combined with 3′-amino-3′-deoxyadenosine. In contrast to previous work on other viruses, the antiviral activity of 13 was mapped to take place in virus replication phase. The efficacy was also shown to be independent of external guanosine supplementation.
