- Unprecedented dual reactivity of anhydrous potassium hydroxide in cascade cyclopropannelation/Haller-Bauer-scission/Grob-fragmentation reactions
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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.
- Krief, Alain,Kremer, Adrian
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- A New Photochemical Synthesis of Cyclopropanecarboxylic Acids Present in Pyrethroids by the Aza-di-?-methane Rearrangement
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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.
- Armesto, Diego,Gallego, Mar G.,Horspool, William M.,Agarrabeitia, Antonia R.
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- Lipase catalysed kinetic resolution of racemic (±)2,2-dimethyl-3-(2-methyl-1-propenyl)-cyclopropane carboxyl esters
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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.
- Bhaskar Rao,Rehman,Krishnakumari,Yadav
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- Electron transfer photochemistry of chrysanthemol: An intramolecular S(N)2' reaction of a vinylcyclopropane radical cation
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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.
- Herbertz, Torsten,Roth, Heinz D.
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- Total Syntheses of All Six Chiral Natural Pyrethrins: Accurate Determination of the Physical Properties, Their Insecticidal Activities, and Evaluation of Synthetic Methods
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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).
- Ashida, Yuichiro,Kawamoto, Momoyo,Matsuo, Noritada,Moriyama, Mizuki,Tanabe, Yoo
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p. 2984 - 2999
(2020/03/24)
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- Cyclopropanation of Terminal Alkenes through Sequential Atom-Transfer Radical Addition/1,3-Elimination
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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.
- Tappin, Nicholas D. C.,Michalska, Weronika,Rohrbach, Simon,Renaud, Philippe
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supporting information
p. 14240 - 14244
(2019/08/26)
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- Clean production method of pyrethroid intermediate chrysanthemic acid
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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.
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Paragraph 0042-0047
(2018/03/26)
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- Syntheses of racemic and scalemic cis-chrysanthemic acid from β,γ-unsaturated cyclohexanol
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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.
- Krief, Alain,Jeanmart, Stéphane,Gondal, Humaira Y.,Kremer, Adrian
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p. 2123 - 2167
(2013/02/23)
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- A practical method for O-acylation of N -hydroxythiazole-2(3 H)-thiones
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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).
- Schur, Christine,Gross, Andreas,Hartung, Jens
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experimental part
p. 538 - 542
(2010/06/13)
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- Betulin-derived compounds as inhibitors of alphavirus replication
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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.
- Pohjala, Leena,Alakurtti, Sami,Ahola, Tero,Yli-Kauhaluoma, Jari,Tammela, Paeivi
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supporting information; experimental part
p. 1917 - 1926
(2010/04/29)
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- BETULIN DERIVED COMPOUNDS USEFUL AS ANTIBACTERIAL AGENTS
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The invention relates to compouns derived from betulin, and to the use thereof as antibacterial agents in pharmaceutical and cosmetic applications.
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Page/Page column 61
(2008/06/13)
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- BETULIN DERIVED COMPOUNDS AS ANTI-FEEDANTS FOR PLANT PESTS
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The invention relates to compounds derived from betulin, and to the use thereof in plant pest control, particularly as antifeedants for butterfly larvae, beetles and snails. Further, the invention relates to novel betulin derivatives and methods for the production thereof either directly from betulin, or via intermediates derived therefrom.
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Page/Page column 36-37
(2008/06/13)
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- OPTICALLY ACTIVE BISOXAZOLINE COMPOUNDS, PROCESS FOR PRODUCTION OF THE SAME AND USE THEREOF
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Optically active bisoxazoline compounds represented by the general formula (1), a process for producing the compounds, and a process for producing cyclopropanecarboxylic esters by using the same: wherein R1 and R2 are the same and each represents C1-6 alkyl, substituted or unsubstituted aralkyl, or substituted or unsubstituted phenyl or R1 and R2 are bonded each other together with the carbon atom of oxazoline ring to which they are bonded to form a ring; R3 is substituted or unsubstituted naphthyl; R4 and R5 are the same and each represent hydrogen or C1-6 alkyl, or R4 and R5 are bonded each other together with the carbon atom to which they are bonded to form a cycloalkyl ring having 3 to 6 carbon atoms; and * represents an asymmetric center.
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(2008/06/13)
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- Process for racemizing optically active vinyl-substituted cyclopropanecarboxylic acid compound
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There is disclosed a process for the racemization of a vinyl-substituted cyclopropanecarboxylic acid or a derivative thereof, which is characterized by reacting an optically active vinyl-substituted cyclopropanecarboxylic acid compound of formula (1): 1wherein R1, R2, R3 and R4 each independently represent a hydrogen atom, a halogen atom, alkyl which may be substituted having 1-4 carbon atoms, aryl which may be substituted, or alkoxycarbonyl which may be substituted, or R1 and R2 are bonded to form an alkylene group, which may be substituted; and wherein X represents hydroxyl, a halogen atom, alkoxy which may be substituted having 1-20 carbon atoms, or aryloxy which may be substituted, with a nitric compound or a nitrogen oxide.
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- Asymmetric Copper-Catalyzed Cyclopropanation of Trisubstituted and Unsymmetrical cis-1,2-Disubstituted Olefins: Modified Bis-Oxazoline Ligands
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The Cu(I) complexes of new bis-oxazolines (3-7) prepared from the corresponding amino alcohols and malono-bis-imidate exhibit high enantioselectivity of up to 94 percent ee in the catalytic cyclopropanation of trisubstituted and unsymmetrical cis-1,2-disubstituted olefins.New diazoacetate reagents have also been developed giving high trans/cis ratios of up to 99:1 trans.
- Lowenthal, Richard E.,Masamune, Satoru
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p. 7373 - 7376
(2007/10/02)
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- Fluorobenzyl esters
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A compound of formula: STR1 wherein R is selected from hydrogen, cyano, methyl, and ethynyl, and X represents the residue of any carboxylic acid of formula X-COOH which forms an insecticidally active ester with a 3-phenoxybenzyl alcohol. The compounds are useful as insecticides and acaricides.
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- Process for producing 3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylates
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Disclosed is a Wittig-type process for preparing 3-(2-chloro-3,3,3-trifluoropropenyl)-2,2-dimethylcyclopropanecarboxylates which comprises reacting 1,1,1-trichlorotrifluoroethane with hexamethylphosphorous triamide at a temperature in the range of about -80° C. to 10° C. in the presence of an inert aprotic solvent and a carbonaldehyde ester, and thereafter maintaining the reaction mixture at a temperature in the range of about 0° C. to 30° C. Also disclosed are the novel caronaldehyde ester (2-methyl[1,1'-biphenyl]-3-yl)methyl 2,2-dimethyl-3-formylcyclopropanecarboxylate and a precursor compound, (2-methyl[1,1'-biphenyl]-3-yl)methyl 2,2-dimethyl-3-(1,2-epoxy-2-methylpropyl)cyclopropanecarboxylate, and methods for producing them.
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- Process for the preparation of optically active cyclopropane carboxylic acids
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The invention relates to a process for the preparation of enantiomers of trans vinyl-cyclopropane carboxylic acids of the formula I, STR1 wherein R is a methyl group or chlorine atom, by resolution of racemic trans compound or mixture of racemic cis and trans compounds by using (+)- or (-)-N-(1-formamido-2,2,2-trichloroethyl)-piperazine as a resolving agent in a polar solvent then separating the crystallizing salt of (+)-trans carboxylic acid and (-)-resolving agent or (-)-trans carboxylic acid and (+)-resolving agent from the mother liquor by filtration and obtaining the enantiomers by acidifying the mother liquor or the salts suspended in water followed by extraction with a solvent and evaporation. The products so obtained may be used as starting materials for the preparation of insecticides.
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- Oxo Complexes of Ruthenium(VI) and (VII) as Organic Oxidants
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Oxidation of a variety of saturated and unsaturated primary and secondary alcohols by tetraoxoruthenate(VI), 2-, tetraoxoruthenate(VII), -, barium trans-trioxodihydroxoruthenium(VI), trans-Ba, dioxotrichlororuthenate(VI), -, and dioxodichlorobipyridylruthenate(VI),, has been studied; 2- may be used catalytically in conjunction with 2- under basic aqueous conditions.For some of these systems, the oxidation of several aldehydes and amines were also examined.Both 2- and - oxidise primary alcohols to carboxylic acids and secondary alcohols to ketones; the reactivity of these reagents towards unsaturated alcohols was studied in particular.The new species and also cleanly oxidise a wide range of alcohols to aldehydes and ketones without attack of double bonds.Ba functions as a heterogeneous oxidant in dichloromethane, oxidising only the most reactive alcohols to aldehydes.
- Green, Graham,Griffith, William P.,Hollinshead, David M.,Ley, Steven V.,Schroeder, Martin
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p. 681 - 686
(2007/10/02)
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- Studies of Chrysanthemic Acid Derivatives: Catalyses Reactions of 3-(2-Hydroxymethyl-3,3-dimethylcyclopropyl)-2-methylpropanol and Formation of a Novel Eight-membered Cyclic Sulphite
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Acid catalysed reaction of the cyclopropanediol (3) derived from cis-chrysanthemic acid cis-(1) afforded, depending on the reaction conditions, 3-vinyl-2,2,5,5-tetramethyltetrahydrofuran (4) and 4,4,7,7-tetramethyl-3-oxabicycloheptane (5).On treatment with thionyl chloride-pyridine complex there was obtained in addition the eight-membered cyclic sulphite, 6,6,9,9-tetramethyl-3,5-dioxa-4-thiabicyclononane 4-oxide (6).X-Ray analysis confirms a boat-chair conformation with the S=O group trans to the cyclopropane ring in an equatorial situation.Thermal reaction of (6) gave either (4) or a mixture of (5), cis-chrysanthemol (7), and cis-isochrysanthemol (8).
- Crammer, Bernard,Goldschmidt, Zeev,Ikan, Raphael,Cohen, Shmuel
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p. 887 - 891
(2007/10/02)
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- Deaminative Rearrangements of 1-Phenylthio- and 1-Oxy-Substituted Chrysanthemylamines
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Metalation of chrysanthemic nitrile 1 with lithium diisopropylamide followed by sulfenylation with diphenyl disulfide or oxygenation with a molybdenum peroxide complex gave chrysanthemic nitrile derivatives bearing phenylthio (3 and 4) or hydroxyl (6) substituents at C-1.These compounds provided access to the following series of 1-substituted chrysanthemylamines: 1-(phenylthio)chrysanthemylamine (5), 1-methoxychrysanthemylamine (8), 1-methoxydihydrochrysanthemylamine (10), and the N-nitrosooxazolidinone (13) derived from 1-hydroxychrysanthemylamine (11).Nitrous acid deamination of 5 and 8 and hydrolytic deamination of 13 gave acyclic alcohols (14, 17, and 18) related in structure to yomogi alcohol as major products by cleavage of the 1-3 cyclopropane ring bond.Products formed by cleavage of the 1-2 cyclopropane ring bond (15 and 24) and related in structure to santolinatriene were obtained in lesser amounts from the deamination of 5 and 13.Pinacol-type ring expansion to the isomeric cyclobutanones 19 and 20 was observed as a minor reaction pathway in the deaminations of 8 and 13.In contrast, deamination of 10 gave dihydrocyclobutanones 21 and 22 as the major isolated products.
- VanCantfort, Christopher K.,Coates, Robert M.
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p. 4331 - 4339
(2007/10/02)
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- Racemization of optically active 2,2-dimethyl-3-(1'-alkenyl)-cyclopropane-1-carboxylic acids
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A method for racemization of optically active 2,2-dimethyl-3-(1'-alkenyl)-cyclopropane-1-carboxylic acids of the formula: STR1 wherein R1 and R2 are each a hydrogen atom or an alkyl group having 1 to 4 carbon atoms or, when taken together with the carbon atom to which they are attached, represent a cycloalkylidene group having 4 to 6 carbon atoms, which comprises the step of contacting the corresponding acid halide with boron halide at a temperature of not more than 20° C.
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- A NOVEL SYNTHESIS OF (+/-)-TRANS-CHRYSANTHEMIC ACID
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A novel approach to (+/-) trans chrysanthemic acid, from commercially avaiable 2,5-dimethyl-3-hexyne-2,5-diol /30 percent overall yield) is described.
- Genet, J.P.,Piau, F.,Ficini, J.
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p. 3183 - 3186
(2007/10/02)
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