- Synthesis of 1-methyl-3-oxo-7-oxabicyclo[2.2.1]hept-5-ene-2-carboxylic acid methyl ester
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A simple and efficient method for the preparation of 1-methyl-3-oxo-7- oxabicyclo[2.2.1]hept-5-en-2-carboxylic acid methyl ester (1) is described. The first step is a highly regioselective Diels-Alder reaction between 2-methylfuran and methyl-3-bromopropiolate. A remarkably difficult ketal hydrolysis reaction was effected by treatment with HCl, a simple reagent that was shown to be more efficient, in this case, than commonly used more elaborate methods.
- Aragao, Valquiria,Constantino, Mauricio Gomes,Beatriz, Adilson,Da Silva, Gil Valdo Jose
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- Asymmetric synthesis of dihydrocarbazoles through a Friedel-Crafts alkylation/annulation sequential reaction of indoles
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An enantioselective tandem Friedel-Crafts alkylation/annulation of indoles with diazoacetoacetate enones is realized in one pot. A series of dihydrocarbazoles were obtained in moderate yields with good to excellent ee values by using a RhII/ScIII dual-metallic catalyst system. Control experiments revealed that ScIII is critical to both the alkylation and annulation.
- Hu, Linfeng,Cao, Weidi,Wang, Kaixuan,Liu, Xiaohua,Feng, Xiaoming
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supporting information
p. 13138 - 13141
(2021/12/16)
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- Environment-friendly preparation method of propiolic acid derivatives
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The invention discloses an environment-friendly preparation method of propiolic acid derivatives. The preparation method comprises the following steps: (1) with 2,3-dibromosuccinic acid as a raw material, generating a butynedioic acid salt under alkaline conditions; (2) under an acidic condition, carrying out high-temperature decarboxylation to obtain propiolic acid; and (3) adding corresponding methanol or ethanol into propiolic acid in an extraction solvent, and preparing high-yield propiolate under acidic catalytic conditions under the condition that trimethyl orthoformate or triethyl orthoformate participates in dehydration. In the invention, the propiolic acid preparation method is friendly to environment and high in safety coefficient; and the method provided by the invention can beused for preparing methyl propiolate and ethyl propiolate, and has the advantages of small alcohol consumption, thorough reaction, high yield and easiness in separation.
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Paragraph 0031-0034
(2020/02/14)
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- Carboxylation of terminal alkynes promoted by silver carbamate at ambient pressure
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Transition metal carbamates constitute a class of compounds with unique properties, however their catalytic potential has been sparingly explored so far. The easily available silver N,N-dimethylcarbamate, Ag(O2CNMe2), worked as a catalyst in the carboxylation reaction of terminal alkynes with CO2 at atmospheric pressure. Different reaction parameters (solvent, base, temperature, time and the amount of catalyst) were investigated in order to establish the optimal conditions.
- Bresciani, Giulio,Marchetti, Fabio,Pampaloni, Guido
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p. 10821 - 10825
(2019/07/15)
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- Oxidant speciation and anionic ligand effects in the gold-catalyzed oxidative coupling of arenes and alkynes
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The mechanism of the gold-catalyzed oxidative cross-coupling of arenes and alkynes has been studied in detail combining stoichiometric experiments with putative reaction intermediates and DFT calculations. Our data suggest that ligand exchange between the alkyne, the Au(i)-catalyst and the hypervalent iodine reagent is responsible for the formation of both an Au(i)-acetylide complex and a more reactive "non-symmetric" I(iii) oxidant responsible for the crucial Au(i)/Au(iii) turnover. Further, the reactivity of the in situ generated Au(iii)-acetylide complex is governed by the nature of the anionic ligands transferred by the I(iii) oxidant: while halogen ligands remain unreactive, acetato ligands are efficiently displaced by the arene to yield the observed Csp2-Csp cross-coupling products through an irreversible reductive elimination step. Finally, the nature of competitive processes and catalyst deactivation pathways has also been unraveled. This detailed investigation provides insights not only on the specific features of the species involved in oxidative gold-catalyzed cross couplings but also highlights the importance of both ancillary and anionic ligands in the reactivity of the key Au(iii) intermediates.
- Hofer, Manuel,De Haro, Teresa,Gómez-Bengoa, Enrique,Genoux, Alexandre,Nevado, Cristina
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p. 8411 - 8420
(2019/09/30)
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- Palladium-Catalyzed Regio- and Stereoselective Coupling-Addition of Propiolates with Arylsulfonyl Hydrazides: A Pattern for Difunctionalization of Alkynes
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A new pattern for difunctionalization of alkynes via a palladium-catalyzed regio- and stereoselective coupling-addition of propiolates with arylsulfonyl hydrazides is disclosed. The approach enables the synthesis of various highly functionalized (E)-vinylsulfones in satisfactory yields. Arylsulfonyl hydrazides act as both aryl and sulfonyl sources via selective cleavage of Ar(C)-S and S-N bonds, which are simultaneously incorporated onto the terminal carbon atom of an alkyne molecule.
- Liu, Lixin,Sun, Kang,Su, Lebin,Dong, Jianyu,Cheng, Lei,Zhu, Xiaodong,Au, Chak-Tong,Zhou, Yongbo,Yin, Shuang-Feng
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supporting information
p. 4023 - 4027
(2018/07/15)
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- Palladium(II) Acetate-Catalyzed Dual C–H Functionalization and C–C Bond Formation: A Domino Reaction for the Synthesis of Functionalized (E)-Bisindole-2-ones from Diarylbut-2-ynediamides
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A domino reaction of palladium(II)-catalyzed dual C–H functionalization with subsequent intramolecular annulation is presented. This method provides a convenient synthesis of a range of symmetrical and unsymmetrical biologically important (E)-bisindole-2-ones under extremely mild reaction conditions – room temperature, green oxidant and no additive. The reaction mechanism is elucidated in light of the yield values as well as additional control experiment results. (Figure presented.).
- Li, Guangchen,Zhou, Guangshuai,Zhang-Negrerie, Daisy,Du, Yunfei,Huang, Jianhui,Zhao, Kang
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supporting information
p. 3534 - 3540
(2016/11/25)
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- Synthesis and evaluation of hybrid molecules targeting the vinca domain of tubulin
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Some hybrids of vinca alkaloids and phomopsin A, linked by a glycine pattern, have been synthesized in one or two steps, by an insertion reaction and shown to inhibit microtubule assembly. These compounds have been elaborated in order to interact with both the "vinca site" and the "peptide site" of the vinca domain in tubulin. Two out of three hybrids are potent inhibitors of microtubules assembly and they present good cytotoxicity against different cell lines. Molecular modelling studies show that they could bind, within the vinca domain, in similar spatial regions as those of vinca and phomopsin thanks to the flexibility provided by the glycine linker used to elaborate these hybrids. This journal is
- Gherbovet,Sánchez-Murcia, Pedro A.,García Alvarez,Bignon,Thoret,Gago,Roussi
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p. 3144 - 3154
(2015/03/18)
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- Syntheses of α-pyrones using gold-catalyzed coupling reactions
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Sequential alkyne activation of terminal alkynes and propiolic acids by gold(I) catalysts yields compounds having α-pyrone skeletons. Novel cascade reactions involving propiolic acids are reported that give rise to α-pyrones with different substitution patterns.
- Luo, Tuoping,Dai, Mingji,Zheng, Shao-Liang,Schreiber, Stuart L.
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supporting information; experimental part
p. 2834 - 2836
(2011/07/07)
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- Boronic acid catalysis for mild and selective [3+2] dipolar cycloadditions to unsaturated carboxylic acids
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Herein, the concept of boronic acid catalysis (BAC) for the activation of unsaturated carboxylic acids is applied in several classic dipolar [3 + 2] cycloadditions involving azides, nitrile oxides, and nitrones as partners. These cycloadditions can be used to produce pharmaceutically interesting, small heterocyclic products, such as triazoles, isoxazoles, and isoxazolidines. These cycloadducts are formed directly and include a free carboxylic acid functionality that can be employed for fur-ther transformations, thereby avoiding prior masking or functionalization. In all cases, BAC provides faster reactions, under milder conditions, with much improved product yields and regioselectivities. In some instances, such as triazole formation from the reaction of azides with 2-alkynoic acids, catalysis with ort/io- nitrophenylboronic acid circumvents the undesirable product decarboxylation observed when using thermal activation. By using NMR spectroscopic studies, the boronic acid catalyst was shown to provide activation by a LUMO-lowering effect in the unsaturated carboxylic acid, likely via a monoacylated hemiboronic ester intermediate.
- Zheng, Hongchao,McDonald, Robert,Hall, Dennis G.
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supporting information; experimental part
p. 5454 - 5460
(2010/09/15)
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- Combination of additives for lubricating oils
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A composition comprising a compound of formula I: wherein W represents O, S—A2, or two groups, R3and R4; bonds a and b are single or double bonds, provided that one of a and b is a single bond and the other is a double bond; c is a single or double bond, and d is a single bond, double bond, or two single bonds, provided that d is a single bond when c is a double bond, d is not a single bond when c is a single bond, and W is R3and R4when d is two single bonds; A1, A2, B1and B2are independently hydrogen, alkyl, alkenyl, aralkyl or one of the groups depicted in Scheme 1: and a dithiophosphate.
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- Preparation of preparing substituted indanones
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a process for the preparation of indanones of the formula II from, indanones of the formula I or of indanones of the formula IIa from indanones of the formula Ia comprises reacting an indanone of the formula I or Ia with a coupling component.
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- Combination of additives for lubricating oils
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A composition comprising a compound of formula I: wherein W represents O, S—A2, or two groups, R3 and R4; bonds a and b are single or double bonds, provided that one of a and b is a single bond and the other is a double bond; c is a single or double bond, and d is a single bond, double bond, or two single bonds, provided that d is a single bond when c is a double bond, d is not a single bond when c is a single bond, and W is R3 and R4 when d is two single bonds; A1, A2, B1 and B2 are independently hydrogen, alkyl, alkenyl, aralkyl or one of the groups depicted in Scheme 1: and a dithiophosphate.
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- Synthesis and characterization of coordinatively unsaturated alkynyl- and aryl-cobalt complexes with 15 valence electrons, TpiPr2Co-R, bearing the hydrotris(3,5-diisopropylpyrazolyl)borato ligand (TpiPr2)
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Coordinatively unsaturated 15e alkynyl- (TpiPr2Co-C≡C-R) and aryl-cobalt complexes (TpiPr2Co-aryl) bearing the hydrotris(3,5-diisopropylpyrazolyl)borato ligand (TpiPr2) are prepared by dehydrative condensation of the hydroxo complex [TpiPr2Co(μ-OH)2]2 with 1-alkyne and arylation of the chloro complex TpiPr2Co-Cl with Grignard reagents, respectively. Spectroscopic and crystallographic analyses reveal the apparent C3-symmetrical tetrahedral structures with high-spin electronic configuration (S = 3/2), which should result from the property of the TpiPr2 ligand as a tetrahedral enforcer. The TpiPr2Co and hydrocarbyl fragments, are connected dominantly through σ-bonding interaction, and π-interaction including back-donation is not significant as revealed by EHMO calculations. The Co-C bonds are so polarized as to be readily protonated even by moisture to give the corresponding hydrocarbons, but the reactivity toward unsaturated hydrocarbons turns out to be sluggish. TpiPr2Co-C≡C-COOMe is found to catalyze a rare example of specific linear trimerization of methyl propiolate to give (E,E)-MeOOC(H)C=CH-CH=C(COOMe)-C≡C-COOMe.
- Yoshimitsu, Shin-Ichi,Hikichi, Shiro,Akita, Munetaka
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p. 3762 - 3773
(2008/10/08)
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- Ruthenium-Dihydrogen Complexes via C-H Cleavage in Alk-1-ynes. Crystal Structure of CPh)(dippe)2>
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The reaction of the monohydride complex + with alk-1-ynes yields the dihydrogen complexes CR)(dippe)2>+ CPh)(dippe)2> has been determined, a
- Tenorio, Manuel Jimenez,Puerta, M. Carmen,Valerga, Pedro
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p. 1750 - 1751
(2007/10/02)
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- Formation and Reaction of Acyl Substituted Nitrile Ylide through the Rh2(OAc)4-Catalyzed Reaction of α-Diazocarbonyl Compounds with Benzonitrile
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The rhodium(II) acetate-catalyzed reaction of α-diazocarbonyl compounds with benzonitrile and dimethyl acetylenedicarboxylate gave oxazoles and pyrrole-3,4-dicarboxylates through the 1,5-cyclization and 1,3-dipolar cycloaddition of the acyl substituted nitrile ylide intermediates generated by the reaction of ketocarbenoids with benzonitrile.
- Ibata, Toshikazu,Fukushima, Kazuaki
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p. 2197 - 2200
(2007/10/02)
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- Reactions retrodieniques XX. Synthese et thermolyse eclair de bis-adduits de Diels-Alder : creation d'une triple liaison fonctionnalisee par double cycloreversion
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La thermolyse eclair de bis-adduits de Diels-Alder appropries peut conduire a des alcynes fonctionnels.Cette reaction a ete testee sur les bis-adduits 1-3 du propiolate de methyle avec le cyclopentadiene, le furanne et l'anthracene respectivement et une double cycloreversion specifique en les composes de depart a ete obtenue a partir de 3.Une application a la mise en evidence de l'ethynol et de l'ethynamine a ete tentee avec la synthese et la thermolyse eclair des bis-adduits 9 et 10.Alors que seuls les tautomeres stables, cetene ou acetonitrile, ont ete detectes par RMN ou spectrometrie de masse, l'analyse par IR a basse temperature montre de plus des bandes faibles disparaissant a - 150 deg C et qui pourraient etre respectivement attribuees a l'ethynol (2230 cm-1) et a l'ethynamine (2160 cm-1).
- Lasne, Marie-Claire,Ripoll, Jean-Louis
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p. 766 - 770
(2007/10/02)
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- Rates of Base-Catalyzed Hydrogen Exchange of Terminal Acetylenes in Aqueous Solution. Absence of Resonance Interaction
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Rates of detritiation of 13 monosubstituted acetylenes labeled at the acetylenic hydrogen position were measured in aqueous amine buffer solution at 25 deg C, and hydroxide ion catalytic coefficients were evaluated.These rate constants, plus a few additional values from the literature, give a good correlation against inductive or field substituent constants: log(kHO-/M-1s-1) = 1.46+/-0.12 + (8.00+/-0.50)?I.This correlation is not improved by addition of resonance substituted constants, and the coefficients of the resonance term in two different dual parameter (resonance plus field) treatments of the data are in fact zero.
- Kresge, A. J.,Powell, M. F.
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p. 819 - 822
(2007/10/02)
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- Esterification, Etherification, and Aldol Condensation Using Cathodically-Generated Organic Olate Anions
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Cathodic methods for the esterification of carboxylic acids and the etherification of phenol and benzenethiol under mild conditions were developed.The esterification was successfully carried out at room temperature by the reaction of alkylating reagents with cathodically-generated quaternary ammonium carboxylates.The etherification was similarly achieved using electrogenerated quaternary ammonium phenolate and halonitrobenzenes.A hindered phenolate anion cathodically-generated from 2,6-di-t-butyl-p-cresol remarkably promoted aldol condensation of aromatic ketones and aldehydes, and allowed subsequent Michael reaction to provide efficiently symmetrical 1,5-diketones.
- Fuchigami, Toshio,Awata, Takeshi,Nonaka, Tsutomu,Baizer, Manuel M.
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p. 2873 - 2880
(2007/10/02)
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- CATHODIC ESTERIFICATION OF CARBOXYLIC ACIDS
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A cathodic method for the esterification of carboxylic acids under mild conditions was found.The esterification proceeded smoothly at room temperature by the reaction of alkylating with quaternary ammonium carboxylates formed in a cathode chamber.
- Awata, Takeshi,Baizer, Manuel M.,Nonaka, Tsutomu,Fuchigami, Toshio
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p. 371 - 374
(2007/10/02)
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- CYCLOPROPANE-1,1 prime -INDENES.
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The relative concentrations of stereoisomers in product mixtures were determined as a function of time by using a combination of analytical techniques: vapor phase chromatography, polarimetry, NMR spectroscopy, and NMR spectroscopy in the presence of an optically active lanthanide shift reagent. The stereochemical reaction kinetics reveal that the Smith mechanism is not a plausible model for one-center epimerization; two trimethylenes, produced through two distinct cyclopropane C-C bond cleavages, are implicated, since all three possible one-center epimerizations are seen.
- Baldwin,Black
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p. 1029 - 1040
(2007/10/02)
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- Pharmaceutical heterocyclic compounds and compositions
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The compounds of the formula: STR1 wherein: R1, R2, R3, R4, R5 and R7, which may be the same or different, each represent hydrogen, hydroxy, alkyl or alkoxy of 1 to 6 carbon atoms, amino, acyl or acylamino of 2 to 6 carbon atoms, alkenyl of 2 to 6 carbon atoms, halogen, or alkoxy of 1 to 6 carbon atoms substituted by phenyl, X is a hydrocarbon chain of 1 to 10 carbon atoms optionally substituted by a hydroxy group, A is oxygen or is absent, Q represents a straight or branched alkylene, alkenylene or alkynylene group of 2 to 6 carbon atoms, and D represents carboxy, 5-tetrazolyl or carboxamido-5-tetrazolyl, and pharmaceutically acceptable salts, esters and amides thereof, are pharmaceutically active, being antagonists of the slow reacting substance of anaphylaxis (SRS-A) or its pathological effects. Pharmaceutical compositions containing the compounds are also described, as well as processes for preparing the compounds.
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