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.
Goldberg et al.
, p. 43,48 (1965)
Allen et al.
, p. 79,82 (1977)
Welch,Valdes
, p. 2108 (1977)
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).
Clean production method of pyrethroid intermediate chrysanthemic acid
-
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.
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).
