- NEW ROUTES TO 1,1-DICHLORO-4-METYL-1,3-PENTADIENE
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1,1,1-trichloro-2-hydroxy-4-methyl-pentene-3 (1b) was chlorinated to afford tri- and tetra-chlorinated compounds 2,3,4.Compounds 2 and 3 were transformed by reductive dechlorination into 1,1-dichloro-4-methyl-1,3-pentadiene.Another route starting from the same alcohol or its isomer was also developed.
- Bitter, Istvan,Toeke, Laszlo,Bende, Zoltan,Karpati-Adam, Eva,Soos, Rudolf
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Read Online
- 5,5-dichloro-2-methyl 2,4-pentadiene preparation method
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The invention relates to the field of pesticides, particularly to a simple preparation method of a permethric acid intermediate 5,5-dichloro-2-methyl 2,4-pentadiene, wherein 3,3-dichloro-2-propenyl phosphate and acetone are subjected to a condensation reaction under the action of an alkali to the product 5,5-dichloro-2-methyl 2,4-pentadiene, According to the present invention, the process route for preparing the permethric acid intermediate 5,5-dichloro-2-methyl 2,4-pentadiene has advantages of mild condition, simple operation, less side reaction, high yield and simple post-treatment, and is suitable for industrial production, wherein the by-product phosphate can be used for the manufacture of fertilizers; and the content and the yield of the target product are relatively high.
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Paragraph 0024; 0025
(2019/05/11)
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- Liebeskind-Srogl cross-coupling on γ-carboxyl-γ-butyrolactone derivatives: Application to the side chain of amphidinolides C and F
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The synthetic approach for the C20-C29 and C20-C34 fragments of amphidinolide F and C was based on an original Liebeskind-Srogl cross-coupling reaction with a glutamic acid-derived building-block. Further highly diastereoselective reduction of the ketone was achieved by using an uncommon Ph3SiH/TBAF/HMPA system. The amphidinolide C side chain was built through a reductive elimination of chiral epoxide to install the stereogenic center at C29.
- Fenneteau, Johan,Vallerotto, Sara,Ferrié, Laurent,Figadère, Bruno
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supporting information
p. 3758 - 3761
(2015/06/08)
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- Asymmetric copper complex and cyclopropanation reaction using the same
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There are disclosed asymmetric copper complex comprising, as components, (a) an optically active bisoxazoline compound of formula (1): wherein R1 and R2 are different and each represent a hydrogen atom, an alkyl group, a cycloalkyl group, or a phenyl or aralkyl group which may be substituted, R3 and R4 each represent a hydrogen atom, an alkyl group, a cycloalkyl group, or a phenyl or aralkyl group which may be substituted, or R3 and R4 may be bonded to each other to form a C3-5 cyclic alkylene group, R5 represents a hydrogen atom or a C1-6 alkyl group, or the two R5 groups may be bonded to each other to represent a C3-5 cyclic alkylene group, (b) a monovalent or divalent copper compound, and (c) a strong acid or a Lewis acid or a mixture thereof, and a process for producing an optically active cyclopropanecarboxylate using the same.
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- Electrochemical Synthesis of 1,1-Dichloro-4-methylpenta-1,3-diene
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Reaction of 1,1,1-trichloro-4-methylpent-3-en-2-ol (2) with inorganic acid halides yielded several polychloroalkenes (3-5).These compounds were utilized for the electrochemical synthesis of 1,1-dichloro-4-methylpenta-1,3-diene (1).
- Fechtel, U.,Matschiner, H.
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p. 545 - 551
(2007/10/02)
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- Simple synthesis of 2-alkenyl- and 2-aryl-substituted 1,1-dichloroethylenes from unsaturated aldehydes
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A three-step synthesis has been proposed for the preparation of 2-alkenyl- and 2-aryl-1,1-dichloroethylenes, involving the conversion of an aldehyde to its acylal (or α-trichloromethylcarbinol), α-trichloromethylcarbinol acetate, and 2-substituted 1,1-dichloro-olefin. The best procedure for the dechloroacetoxylation by the action of zinc powder in a mixture of acetic acid and ether.
- Zhdankina,Kryshtal',Serebryakov,Yanovskaya
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p. 2589 - 2591
(2007/10/02)
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- REGIOSPECIFICITY IN THE NUCLEOPHILIC RING OPENING REACTIONS OF gem-DICHLOROCYCLOPROPYLCARBINYL CATIONS
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gem-Dichlorocyclopropylcarbinyl cations, generated under acidific conditions from the corresponding alcohol or alkene, undergo ring opening by nucleophilic attack exclusively at the halogenated carbon when the alternative electrophilic ring carbon is unsubstituted.In one case, a novel trifluoroacetoxydichloromethyl function has been produced and characterized as a masked carboxylic acid chloride.
- DeWeese, F. Thane,Minter, David E.,Nosovitch, John T.,Rudel, Michael G.
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p. 239 - 244
(2007/10/02)
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- Preparation of 1,1-dihalogeno-alkenes
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In the preparation of a 1,1-dihalogenoalkene of the formula STR1 in which R1 is a hydrogen atom or an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, aralkyl, aralkenyl or aryl radical, and R2 is an optionally substituted alkyl, alkenyl, alkynyl, cycloalkyl, aralkyl, aralkenyl or aryl radical, or R1 and R2 together form an optionally branched and/or optionally benzo-fused hydrocarbon chain, and X1 and X2 each independently is a halogen atom, wherein a carbonyl compound of the formula STR2 is reacted with a trihalogenoacetate of the formula STR3 in which X3 is a halogen atom, and M≈ is an alkali metal ion or one equivalent of an alkaline earth metal ion, in the presence of an approximately equimolar amount of a phosphorus-containing compound, the improvement which comprises employing as said phosphorus-containing compound a phosphorous acid trialkyl ester or a phosphorous acid triamide and effecting the reaction at a temperature between about 0° and 200° C. A preferred end product is STR4 and the preferred phosphorus-containing compound is trimethyl phosphite, triethyl phosphite, tripropyl phosphite or phosphorous acid tris-dimethyl-amide.
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- Process for the preparation of unsaturated geminal dihalogen compounds
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The invention relates to a new process for preparing unsaturated geminal dihalogen compounds. More particularly, the invention concerns a process for preparing compounds of the formula (I) STR1 wherein X is halogen, R1 is a straight or branched chained alkenyl group having 2 to 6 carbon atoms, by clearing the corresponding 1-substituted 2,2,2-trihaloethylesters.
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- Process for the preparation of 1,1-dichloroalkenes
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A process for the preparation of a 1,1-dichloroalkene of the formula STR1 in which R1 is hydrogen or an optionally substituted alkyl, alkenyl, alkynyl, aralkyl or aryl radical, and R2 is an optionally substituted alkyl, alkenyl, alkynyl, aralkyl, aralkenyl or aryl radical, or cycloalkyl which is optionally substituted by halogen, alkyl, alkanoyl, carbamoyl, cyano or phenyl, or R1 and R2 together form a hydrocarbon chain which is optionally branched and/or optionally contains a fused benzene ring, comprising reacting an aldehyde or ketone of the formula STR2 with a dichloromethane-phosphonic acid ester of the formula STR3 in which R3 each independently is alkyl or phenyl or the two radicals R3 together are alkanediyl, in the presence of a base at a temperature between about -50° and +50° C. Preferably either the base is metered into a mixture of the aldehyde or ketone and phosphonic acid ester or the ester is added to a mixture of the base and aldehyde or ketone.
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- Manufacture of gamma halogen substituted adducts
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Halogen-substituted olefin addition compounds that contain a carbonyl group are formed by oxidatively adducting an olefin and a carbonyl compound such as a ketone, aldehyde, or ester. The method consists of reacting the olefin and the carbonyl component, in solution, with an oxidizing ion of manganese, cerium or vanadium in the presence of fluoride, chloride or bromide ion. This ionic component is incorporated in the adduct and appears on the olefin-derived carbon atom gamma to the carbonyl group. The gamma halogen substituted adducts are readily converted to cyclopropane derivatives, including pyrethroid intermediate compounds.
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- 1,1-Dichloro-4-methyl-3-hydroxy-pent-1-ene
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A 1,1-dichloro-4-methyl-3-hydroxy-pent-1-ene and a process for its production.
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- Process for the preparation of 1,1-dihalo-4-methyl-1,3-pentadiene compounds
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Process for making 1,1-dihalo-4-methyl-1,3-pentadiene compounds which process comprises reacting a 2-2-dimethyl-3,5,5,5-tetrahelogenopent-1-yl derivative of the formula STR1 in which Hal1 is defined as above, Hal2 is halogen, and R is hydrogen or alkanoyl of up to 5 carbon atoms with a substance having a basic reaction in a temperature range from 20° to 160° C. Certain intermediates produced in such process can also be used as the initial starting material.
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- (2,2-Disubstituted vinyl)γ-butyrolactones
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(2,2-Disubstituted vinyl)-γ-butyrolactones of the formula: STR1 in which R1 and R2 are hydrogen or C1 -C6 alkyl, preferably methyl, R3 and R4 are hydrogen, C1 -C6 alkyl, preferably methyl, or halogen, or, together with the carbon atom to which they are attached, form a cycloalkyl group, and R5 is C1 -C6 alkyl, are prepared by condensing an epoxide of the formula: STR2 with a malonic acid ester of the formula: STR3 in a basic medium. The butyrolactones of formula I are valuable intermediates for the synthesis of synthetic pyrethroids having insecticidal activity.
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- Process to 1,1-dihalo-4-methyl-1,3-pentadienes, pyrethroid insecticide intermediates
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1,1-Dihalo-4-methyl-1,3-pentadienes, key intermediates in the synthesis of insecticidal dihalovinylcyclopropanecarboxylates, result from the condensation of 3-methyl-1-butene with a carbon tetrahalide in the presence of a catalyst, followed by the base-induced dehydrohalogenation of the 1,1,1,3-tetrahalo-4-methylpentane resulting from the condensation.
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- Process for preparing 1,1-dihalo-4-methyl-1,3-pentadienes
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1,1-Dihalo-4-methyl-1,3-pentadienes, key intermediates in the syntehsis of insecticidal dihalovinylcyclopropanecarboxylates, may be prepared in three steps beginning with the Friedel Crafts condensation of a vinylidene halide and an isobutyryl halide in the presence of a Lewis acid catalyst, followed by reduction of the 1,1-dihalo-4-methyl-1-penten-3-one produced thereby, and dehydration of the resulting 1,1-dihalo-3-hydroxy-4-methyl-1-pentene.
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- Process for the preparation of dienes
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A process for the preparation of a diene of the formula STR1 in which X and Y are independently fluorine, chlorine or bromine Which comprises contacting a 1,1,1-trihalo-4-methyl-4-hydroxypentane of the formula STR2 in which X and Y have the previously assigned significance and Z is a chorine or bromine atom With a dehydrohalogenating agent and a dehydration agent.
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- Electrochemical synthesis of insecticide intermediates
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1,1,1-Trihalo-4-methylpentenes, carrying 2-substituents selected from those conjugate bases of Bronsted acids which are leaving groups in beta eliminations, are reduced electrochemically to 1,1-dihalo-4-methylpentadienes, intermediates in the synthesis of pyrethroid insecticides.
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- 1,1,1-Trihalogeno-4-methylpentenes, method of preparing the same and use of the same in the preparation of 1,1-dihalogeno-4-methyl-1,3-pentadienes
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1,1,1-Trihalogeno-4-methyl pentenes and 1,1-dihalogeno-4-methyl-1,3-pentadienes are produced. These compounds are of value as intermediates for the production of pyrethrin analogs which are of use as insecticides or agricultural chemicals.
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