- 1-alkenylcalcium iodide: Synthesis and stability
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To enhance the scope of heavy calcium-based Grignard reagents, 1,2-dihydro-4-iodonaphthalene (1) was reduced with calcium in THF giving tetrakis(thf) (1,2-dihydronaphth-4-yl)calcium iodide (2). This derivative represents a 1-alkenylcalcium complex based on X-ray structure determination and NMR data. The stability of this compound is significantly reduced compared with the aromatic naphthylcalcium iodide. Complex diversity: The class of heavy Grignard reagents is extended by a 1-alkenylcalcium iodide. This tetrakis(thf) (1,2-dihydronaphth-4-yl)calcium iodide contains a 1-alkenyl moiety based on structural and NMR spectroscopic studies (see figure).
- Koehler, Mathias,Goerls, Helmar,Langer, Jens,Westerhausen, Matthias
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Read Online
- Microenvironment Engineering of Ruthenium Nanoparticles Incorporated into Silica Nanoreactors for Enhanced Hydrogenations
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It is a challenging task to promote the activity and selectivity of a catalyst via precisely engineering the microenvironment, an important factor related with the catalytic performance of natural catalysts. Motivated by the water effect in promoting the
- Ren, Xiaomin,Guo, Miao,Li, He,Li, Chengbin,Yu, Liang,Liu, Jian,Yang, Qihua
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Read Online
- Macrolactam Synthesis via Ring-Closing Alkene-Alkene Cross-Coupling Reactions
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Reported herein is a practical method for macrolactam synthesis via a Rh(III)-catalyzed ring closing alkene-alkene cross-coupling reaction. The reaction proceeded via a Rh-catalyzed alkenyl sp2 C-H activation process, which allows access to macrocyclic molecules of different ring sizes. Macrolactams containing a conjugated diene framework could be easily prepared in high chemoselectivities and Z,E stereoselectivities.
- Goh, Jeffrey,Loh, Teck-Peng,Maraswami, Manikantha
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supporting information
p. 9724 - 9728
(2020/12/21)
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- Preparation method of cyclohexenecarboxylic acid
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The invention discloses a preparation method of cyclohexenecarboxylic acid. The preparation method comprises the following steps of S1, preparing a catalyst: weighing sodium tungstate, performing dissolving with water, slowly dropwise adding hydrochloric
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Paragraph 0014-0023
(2020/12/08)
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- Synthetic method for 3-acetoxy-2-cyclohexenyl-1-one and derivatives thereof
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The invention discloses a synthetic method for 3-acetoxy-2-cyclohexenyl-1-one and derivatives thereof. The synthetic method comprises the following steps: (1) reacting a substance as described in thespecification with nitromethane at 110 DEG C to obtain a product I as described in the specification, wherein R in the product I is H or CH3; (2) reacting the product I of the step (1) with sodium nitrite and acetic acid at 37 DEG C to obtain a product II as described in the specification; (3) reacting the product II of the step (2) with methanol and concentrated sulfuric acid at 88 DEG C to obtain a product III as described in the specification; and (4) weighing the product III of the step (3), potassium carbonate, palladium on activated carbon and t-butyl hydroperoxide, adding the weighed materials into dichloromethane, carrying out a reaction at 0 DEG C, and allowing temperature to naturally rise to room temperature so as to obtain a product IV, wherein R in the product IV is H or CH3.The synthetic method of the invention is simpler and more efficient, and has high total yield; the toxicity of reagents used in the preparation is smaller than the toxicity of m-methoxybenzoic acid, thionyl chloride and the like used in the prior art; and the method is low in cost, simple and convenient in separation and purification, applicable to large-scale preparation and capable of realizingindustrial mass production. The synthetic method is applicable as a general synthetic method for 3-acetoxy-2-cyclohexenyl-1-one and 4-substituted derivatives thereof.
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Paragraph 0019; 0021; 0023
(2019/10/01)
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- Palladium catalyzed carbonylations of alkenyl halides with formic acid to get corresponding Α,Β-unsaturated carboxylic acids and esters
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Palladium-catalysed carbonylation reactions have been developed in the presence of formic acid as carbon monoxide source. α,β-Unsaturated carboxylic acids and esters were synthesized by the transformation of alkenyl halides in moderate to good yields. The selection of the base proved to be crucial regarding the reaction outcome. A set of various substrates were proven under optimised reaction conditions. Compared to aliphatic alcohols, phenols showed excellent reactivity as O-nucleophiles.
- Bartal, Brigitta,Mikle, Gábor,Kollár, László,Pongrácz, Péter
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p. 143 - 149
(2019/02/15)
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- Iodine-Catalyzed Nazarov Cyclizations
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The Nazarov cyclization is an important pericyclic reaction that allows the synthesis of substituted cyclopentenones. We now demonstrate that this reaction can be performed under very mild, metal-free reaction conditions using molecular iodine as the catalyst. A variety of different divinyl ketones including aromatic systems undergo the iodine-catalyzed reaction with moderate to very good yields in both polar and apolar solvents. Our mechanistic studies indicate that the Nazarov system is activated through a halogen bond between the carbonyl group and the catalyst, and other modes of action like Br?nsted acid or iodonium ion catalysis are unlikely. Furthermore, addition of iodine to the double bond or a putative iodine-catalyzed cis-trans isomerization of the employed olefins seem not to be an important side reaction here.
- Koenig, Jonas J.,Arndt, Thiemo,Gildemeister, Nora,Neud?rfl, J?rg-M.,Breugst, Martin
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p. 7587 - 7605
(2019/06/27)
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- Zinc Oxide-Catalyzed Dehydrogenation of Primary Alcohols into Carboxylic Acids
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Zinc oxide has been developed as a catalyst for the dehydrogenation of primary alcohols into carboxylic acids and hydrogen gas. The reaction is performed in mesitylene solution in the presence of potassium hydroxide, followed by workup with hydrochloric acid. The transformation can be applied to both benzylic and aliphatic primary alcohols and the catalytically active species was shown to be a homogeneous compound by a hot filtration test. Dialkylzinc and strongly basic zinc salts also catalyze the dehydrogenation with similar results. The mechanism is believed to involve the formation of a zinc alkoxide which degrades into the aldehyde and a zinc hydride. The latter reacts with the alcohol to form hydrogen gas and regenerate the zinc alkoxide. The degradation of a zinc alkoxide into the aldehyde upon heating was confirmed experimentally. The aldehyde can then undergo a Cannizzaro reaction or a Tishchenko reaction, which in the presence of hydroxide leads to the carboxylic acid.
- Monda, Fabrizio,Madsen, Robert
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supporting information
p. 17832 - 17837
(2018/11/23)
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- Macrolide Synthesis through Intramolecular Oxidative Cross-Coupling of Alkenes
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A RhIII-catalyzed intramolecular oxidative cross-coupling between double bonds for the synthesis of macrolides is described. Under the optimized reaction conditions, macrocycles containing a diene moiety can be formed in reasonable yields and with excellent chemo- and stereoselectivity. This method provides an efficient approach to synthesize macrocyclic compounds containing a 1,3-conjugated diene structure.
- Jiang, Bing,Zhao, Meng,Li, Shu-Sen,Xu, Yun-He,Loh, Teck-Peng
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supporting information
p. 555 - 559
(2018/02/21)
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- Preparation of cyclopentyl (f) ene-1-boronic acid frequency that ester method
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The invention discloses a method of preparing cyclopenten/cyclohexen-1-yl-boronic acid pinacol ester from methyl 1-cyclopentene/cyclohexene-1-carboxylate by three-step continuous operations. The method includes subjecting the raw material to alkaline hydrolysis to form the corresponding 1-alkylene carboxylic acid; performing addition with bromine; performing elimination and decarboxylation at the same time under the existence of DBU or DMAP to produce 1-bromo cyclopentene/cyclohexene; and allowing the 1-bromo cyclopentene/cyclohexene and methoxyboronic acid pinacol ester to form an ester under the existence of magnesium metal by a one-pot process to obtain the cyclopenten/cyclohexen-1-yl-boronic acid pinacol ester. The method is high in continuity, simple and convenient in operations, free of low-temperature reactions, and capable of obtaining the 1-bromo cyclopentene/cyclohexene intermediate with high purity and meeting market demands. The method adopts one-pot-process of Grignard reaction/esterification, so that the method is more convenient in operations and has less by-products, and the product is easier in rectification purification.
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Paragraph 0021; 0022
(2016/10/31)
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- Direct ortho-thiolation of arenes and alkenes by nickel catalysis
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The direct thiolation of arenes and alkenes with diaryl disulfides was developed by nickel catalysis. The reaction displayed exceptional compatibility with a wide range of functional groups to regioselectively give the diaryl sulfides and alkenyl sulfides in high yields.
- Lin, Cong,Li, Danyang,Wang, Binjie,Yao, Jinzhong,Zhang, Yuhong
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p. 1328 - 1331
(2015/03/14)
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- Enzyme cascade reactions: Synthesis of furandicarboxylic acid (FDCA) and carboxylic acids using oxidases in tandem
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A one-pot tandem enzyme reaction using galactose oxidase M3-5 and aldehyde oxidase PaoABC was used to convert hydroxymethylfurfural (HMF) to the pure bioplastics precursor FDCA in 74% isolated yield. A range of alcohols was also converted to carboxylic acids in high yield under mild conditions.
- McKenna, Shane M.,Leimkühler, Silke,Herter, Susanne,Turner, Nicholas J.,Carnell, Andrew J.
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supporting information
p. 3271 - 3275
(2015/06/25)
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- Solvent and structural effects on the activation parameters of the reaction of carboxylic acids with diazodiphenylmethane
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The kinetics of the reaction of benzoic, 2-methylbenzoic, phenylacetic, cyclohex-1-enecarboxylic, 2-methylcyclohex-1-enecarboxylic, and cyclohex-1-eneacetic acids with diazodiphenylmethane was studied at 30, 33, 37, 40, and 45°C in a set of 12 protic and aprotic solvents. The reactions were found to follow the second-order kinetics. The activation energy as well as the activation parameters, such as the standard entropy, the standard enthalpy, and the standard Gibbs energy of the activation, was calculated from the second-order rate constants. The solvent and structural effects on the activation energy and the standard Gibbs energy of activation, for each examined compound, were analyzed. The results of Kamlet-Taft multiple correlation analysis show that the specific solvent-solute interactions play a dominant role in the governing of the reaction. The signs of the equation coefficients support the proposed reaction mechanism.
- Nikolic,Uscumlic
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p. 256 - 265
(2013/04/24)
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- Improved synthesis and in vitro study of antimicrobial activity of α,β-unsaturated and α-bromo carboxylic acids
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A series of α,β-unsaturated and α-bromo carboxylic acids were identified as potent antimicrobial agents. The antimicrobial activity was evaluated using the broth microdilution method. All acids 1-12 exhibited a significant activity against nine laboratory control strains of bacteria and two strains of yeast Candida albicans. The tested acids were efficiently prepared by optimized phase-transfer-catalyzed (PTC) reactions of ketones with bromoform and aqueous lithium hydroxide in alcoholic solvent with triethylbenzyl ammonium chloride (TEBA) as catalyst.
- Vitnik, Vesna D.,Milenkovi, Marina T.,Dilber, Sanda P.,Vitnik, Zeljko J.,Juranic, Ivan O.
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scheme or table
p. 741 - 750
(2012/10/07)
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- One-step conversion of ketones to conjugated acids using bromoform
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Phase-transfer-catalyzed (PTC) reactions of ketones with bromoform and aqueous lithium hydroxide in alcoholic solvent result in the formation of ,-unsaturated carboxylic acids. The reaction was performed at room temperature for 24h. The corresponding conj
- Vitnik,Ivanovic,Vitnik,Orevic,Zizak,Juranic,Juranic
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experimental part
p. 1457 - 1471
(2009/09/26)
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- Selective oxidation of aromatic primary alcohols to aldehydes using molybdenum acetylide oxo-peroxo complex as catalyst
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Selective oxidation of various aromatic alcohols to aldehydes has been carried out with very high conversion (90%) and selectivity (90%) for aldehydes using cyclopentadienyl molybdenum acetylide complex, CpMo(CO)3(C{triple bond, long}CPh) (1) as catalyst and hydrogen peroxide as environmentally benign oxidant. Water-soluble Mo acetylide oxo-peroxo species is formed in situ after reaction of 1 with aqueous hydrogen peroxide during the course of reaction as catalytically active species. Interestingly even though the catalyst is homogeneous it could be recycled very easily by separating the products in organic phase and catalyst in aqueous phase using separating funnel. Even after five recycles no appreciable loss in alcohol conversion and aldehyde selectivity was observed.
- Biradar, Ankush V.,Dongare, Mohan K.,Umbarkar, Shubhangi B.
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experimental part
p. 2885 - 2888
(2009/09/06)
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- The chemoselective and efficient deprotection of silyl ethers using trimethylsilyl bromide
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An efficient and chemoselective cleavage of silyl ethers (primary, secondary and aromatic) by using catalytic quantities of trimethylsilyl bromide (TMSBr) in methanol is reported. A wide range of alkyl silyl ethers such as TBS, TIPS, and TBDPS can be chemoselectively cleaved in high yield in the presence of aryl silyl ethers. The deprotection of silyl esters was also achieved employing catalytic quantities of TMSBr. The Royal Society of Chemistry 2008.
- Shah, Syed Tasadaque A.,Guiry, Patrick J.
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experimental part
p. 2168 - 2172
(2009/02/01)
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- Palladium-catalyzed hydroxycarbonylation of aryl and vinyl triflates by in situ generated carbon monoxide under microwave irradiation
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An operationally simple hydroxycarbonylation of aryl and vinyl inflates to the corresponding carboxylic acids with a palladium-mediated microwave system was carried out in water. Georg Thieme Verlag Stuttgart.
- Lesma, Giordano,Sacchetti, Alessandro,Silvani, Alessandra
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p. 594 - 596
(2007/10/03)
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- Tandem alkylation-cyclization process via an O,C-dianion
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A general protocol for preparing densely functionalized cyclopentenones through a tandem nucleophilic addition-deprotonation-alkylation-cyclization process is described. Addition of lithioallene 2 to enamides 1 generates tetrahedral intermediate 3. Deprotonation of the γ carbon atom of the allene function in situ, followed by trapping by a suitable electrophile and cyclization during workup leads to C6 substituted cyclopentenones 6.
- Banaag, April R.,Berger, Gideon O.,Dhoro, Francis,Delos Santos, Derrick B.,Dixon, Darryl D.,Mitchell, James P.,Tokeshi, Bradley K.,Tius, Marcus A.
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p. 3419 - 3428
(2007/10/03)
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- Synthesis of α,β-unsaturated carboxylic acids by nickel(II)-catalyzed electrochemical carboxylation of vinyl bromides
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Electrochemical carboxylation of alkyl-substituted vinyl bromides (1a-1g) in the presence of 20 mol% of NiBr2?bpy under an atmospheric pressure of carbon dioxide with a platinum cathode and a magnesium anode gave the corresponding α,β-unsaturated carboxylic acids (2a-2g) in yields of 53-82%.
- Kamekawa, Hisato,Kudoh, Hiroki,Senboku, Hisanori,Tokuda, Masao
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p. 917 - 918
(2007/10/03)
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- A New Indirect Application of Aggregative Activation: Synthesis of Esters by Cobalt-Catalyzed Carbonylation of Aryl, Heterocyclic, and Vinyl Halides under Atmospheric Pressure
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Sun lamp illuminated alkoxycarbonylation of aryl, heteroaryl, and vinyl halides was performed under atmospheric pressure of CO in the presence of a cobalt catalyst in situ generated from Co(OAc)2.Illunination through a Pyrex flask was sufficient to catalyze the reaction.This process avoids the use of Co2(CO)8 and excess CH3I, which were required in the earlier procedure.A SRN1 mechanism is proposed.
- Marchal, Joel,Bodiguel, Jacques,Fort, Yves,Caubere, Paul
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p. 8336 - 8340
(2007/10/02)
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- Structure-activity relationships of unsaturated analogues of valproic acid
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The principal metabolite of valproic acid (VPA), 2-ene VPA, appears to share most of VPA's pharmacological and therapeutic properties while lacking its hepatotoxicity and teratogenicity, thus making it a useful lead compound for the development of safer antiepileptic drugs. Analogues of 2-ene VPA were evaluated for anticonvulsant activity in mice using the subcutaneous pentylenetetrazole test. Cyclooctylideneacetic acid exhibited a potency markedly exceeding that of VPA itself with only modest levels of sedation. Potency, as either ED50 or brain concentration, was highly correlated (r > 0.85) with volume and lipophilicity rather than with one of the shape parameters calculated by molecular modeling techniques, arguing against the existence of a specific receptor site. Instead, a role for the plasma membrane in mediating the anticonvulsant effect is suggested.
- Palaty,Abbott
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p. 3398 - 3406
(2007/10/02)
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- Dienediolates of Unsaturated Carboxylic Acids in Synthesis. Synthesis of Cyclohexenones and Polycyclic Ketones by Tandem Michael-Dieckmann Decarboxylative Annulation of Unsaturated Carboxylic Acids.
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Substituted 2-cyclohexenones 4 to 7 and hexahydronaphthalenones and hexahydroindenones 13 to 18 are prepared by tandem Michael-Dieckmann addition of lithium dienediolates of acyclic and alicyclic unsaturated carboxylic acids to the lithium salts of the same or other unsaturated carboxylic acids.
- Aurell, Maria J.,Gavina, Pablo,Mestres, Ramon
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p. 2571 - 2582
(2007/10/02)
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- Preferential Oxygenation of 4-Cycloalkylideneoxazol-5(4H)-ones: Synthesis of N-Acylcycloalk-1-enecarboxamides
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The addition of oxygen, in the presence of base, to 4-cycloalkylideneoxazol-5(4H)-ones led to new substituted N-acylcycloalkenecarboxamides in high yiedl, via base-catalysed isomerisation, oxygenation and subsequent fragmentation of a hydro- or endo-peroxide intermediate.
- Lalitha, Nagabundi,Bhalerao, Uday Triamakraj,Iyengar, Divi Sarangapani
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p. 737 - 738
(2007/10/02)
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- The Reactivity of 2-Substituted Cyclohex-1-enecarboxylic Acid With Diazodiphenylmethane in Various Alcohols
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The reactivities of 2-substituted cyclohex-1-enecarboxylic acids with diazodiphenylmethane in several alcohols were investigated.The rate data for these acids were correlated with a simple Hammett equation by means of the ?p constants.The transmission of polar effects through the double bond, in terms of polar susceptibility constant ρ, has been discussed.For the reactions of a given acid in the various alcohols, the log k and ρ values were correlated through multiple regression on appropriate solvent parameters.The results obtained for 2-substituted cyclohex-1-enecarboxylic acids were compared with the results for ortho-substituted benzoic acids under the same experimental conditions.
- Uscumlic, Gordana S.,Krstic, Vera V.,Muskatirovic, Milan D.
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p. 999 - 1002
(2007/10/02)
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- Antiparasitic agents
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The invention provides novel compounds having the formula: STR1 wherein R when taken individually is H; R1 when taken individually is H or OH; R and R1 when taken together represent a double bond; R2 is an alpha-branched C3 -C8 alkyl, alkenyl, alkynyl, alkoxyalkyl or alkylthioalkyl group; a C3 -C8 cycloalkyl, C5 -C8 cycloalkenyl or C5 -C8 cycloalkylalkyl group, any of which may be substituted by methylene or one or more C1 -C4 alkyl groups or halo atoms; or a 3 to 6 membered oxygen or sulphur containing heterocyclic ring which may be substituted by one or more C1 -C4 alkyl groups or halo atoms; R3 is hydrogen or methyl; R4 is H or 4'-(alpha-L-oleandrosyl)-alpha-L-oleandrosyloxy with the proviso that when R2 is alkyl it is not isopropyl or sec-butyl; when R4 is H, each of R and R1 is H, and R2 is not methyl or ethyl; and when R4 is H, R is H, R1 is OH, and R2 is not 2-buten-2-yl, 2-penten-2-yl or 4-methyl-2-penten-2-yl. The compounds are broad spectrum antiparasitic agents having utility as anthelmintics, ectoparasiticides, insecticides and acaricides. The invention also provides a process for producing the novel avermectin and milbemycin derivatives by adding a carboxylic acid or derivative thereof to a fermentation of an avermectin or milbemycin producing organism.
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- Straightforward Synthesis of 2-Alkenoic Acids from the Corresponding Saturated Aldehydes
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2-Alkenoic acids may be prepared in good yields from saturated aldehydes via α-selenenylation with 4-(phenylseleno)morpholine formed in situ, followed by hydrogen peroxide oxidation.The actual oxidizing agent is benzeneperseleninic acid which is formed in the reaction medium.
- Outurquin, Francis,Paulmier, Claude
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p. 690 - 691
(2007/10/02)
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- STEREOSPECIFIC NICKEL AND PHASE TRANSFER CATALYZED CARBONYLATION OF VINYL BROMIDES AND CHLORIDES
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Nickel cyanide catalyzes the carbonylation of vinyl bromides and chlorides to α,β-unsaturated acids.
- Alper, Howard,Amer, Ibrahim,Vasapollo, Giuseppe
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p. 2615 - 2616
(2007/10/02)
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- Sunlamp-Irradiated Phase-Transfer Catalysis. 1. Cobalt Carbonyl Catalyzed SRN1 Carbonylations of Aryl and Vinyl Halides
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Cobalt carbonyl catalyzed carbonylation (1 atm) of aryl and vinyl halides may be easily achieved under phase-transfer-catalysis conditions provided that the reaction medium is irradiated.Irradiation may be achieved by a commercial sunlamp.Most of these reactions may also be performed without organic solvent and in some cases without a phase-transfer agent.Finally, this new, inexpensive carbonylation method allows very efficient synthesis of benzolactams and benzolactones.
- Brunet, Jean-Jacques,Sidot, Christian,Caubere, Paul
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p. 1166 - 1171
(2007/10/02)
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- ASYMMETRIC HALOLACTONISATION REACTION-4 ASYMMETRIC SYNTHESIS OF OPTICALLY ACTIVE α,β-EPOXYALDEHYDES FROM α,β-UNSATURATED ACIDS
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The bromolactones (5) stereoselectively produced by the asymmetric bromolactonisation of (S)-N-(α,β-unsaturated)acylprolines (3), were elaborated to highly optically active 2(R),3(S)-epoxyaldehydes (8) (84-98percent ee) by successive epoxide formation and reductive cleavage of the proline moiety.The overall process constitutes a highly efficient asymmetric synthesis of 8 from α,β-unsaturated acids (1).
- Hayashi, M.,Terashima, S.,Koga, K.
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p. 2797 - 2803
(2007/10/02)
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- Studies on the rearrangement of (trichloromethyl)carbinols to α-chloroacetic acids
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Phenyl(trichloromethyl)carbinol undergoes an unimolecular, predominantly intramolecular conversion into potassium α-chlorophenylacetate on stirring with 10percent aqueous potassium hydroxide at 0 deg C for several days.Besides providing an interesting example of a 1-2 chlorine shift, the reaction is of potential importance for the synthesis of α-chloro acids.The study of a variety of (trichloromethyl)carbinols shows the reaction is general for secondary (trichloromethyl)carbinols as well as trichloroethanol.The mechanism of the reaction involves the preliminary formation of an epoxide.Several mechanisms are considered for the conversion of the epoxide to the α-chloroacetate anion, but none accounts for all of the experimental facts.Tertiary carbinols break down at the epoxide stage into a ketone and carbon monoxide.
- Reeve, Wilkins,McKee, James R.,Brown, Robert,Lakshmanan, Sitarama,McKee, Gertrude A.
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p. 485 - 493
(2007/10/02)
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