- HETEROGENOUS PHASE TRANSFER CATALYSTS. 1. SYNTHESIS AND CATALYTIC PROPERTIES OF POLYMERIC CROWN -ETHERS ON INORGANIC SUPPORTS
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A number of new heterogeneous phase transfer catalysts based on polymeric dibenzo-crown-ethers supported on the carbonaceous material "Sibunite", ultrafine diamonds, or silica gel are synthesized.The activity of several of the catalysts for the reaction of 1-bromooctane with KI is higher than that of previously known analogs.The catalytic effect depends on the support, linker, and solvent.
- Loktev, V. F.,Morozova, I. Yu.,Tashmukhamedova, A. K.,Likholobov, V. A.
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- Cation participation in nucleophilic substitution reactions promoted by complexes of polyether ligands with alkali and alkaline-earth metal salts
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Cation electrophilic catalysis has been studied in nucleophilic substitution reactions of octyl methanesulfonate (1) promoted by complexes of macrocyclic polyethers 2-5 with alkali and alkaline-earth metal salts in chlorobenzene. The catalytic effect increases with increasing Lewis acid character of the cation, in the order Cs+ ～ Rb+ ～ K+ + + and Ba2+ 2+ 2+, and is mainly related to the ability of the polyether to shield the metal ion charge. Kinetic data clearly indicate that crown ethers 2-4 allow the metal ion participation in the activation process, whereas the cryptand [2.2.2,C10] (5), which more effectively binds the cation, inhibits catalysis. The lower reactivity of the complexes of alkaline-earth metal salts with both crown ethers and cryptands is most likely due to a higher interaction of the divalent cation with the anion in the ion-pair.
- Gobbi, Alessandro,Landini, Dario,Maia, Angelamaria,Penso, Michele
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- Aggregation behavior of sodium 3-(octyloxy)-4-nitrobenzoate in aqueous solution
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Ester 3-(octanoyloxy)-4-nitrobenzoic acid is a standard for the assay of the activity of phospholipase enzymes (the main toxins involved in tissue-damaging after snake bites). Because of its amphiphilic nature, it probably behaves as a surfactant but the instability of the ester bond prevents its characterization. Its ether analogue, 3-(octyloxy)-4-nitrobenzoic acid, is also an interesting compound as it is an inhibitor of the phospholipase activity and can be accepted as a model of the ester derivative. Its sodium salt, stable at basic pH, was studied by surface tension measurements, isothermal titration calorimetry, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The aggregation number, fraction of bound counterions, critical micelle concentration and thermodynamic parameters involved in demicellization were obtained. The positive value for the change in the heat capacity for demicellization indicates that a larger hydrophobic surface area of each monomer is exposed to a hydrophilic environment after dissociation. Semiempirical calculations are in agreement with DLS and TEM measurements. For several carboxylate surfactants, the plot of enthalpy vs. entropy is linear. Although the slope has been named the compensation temperature, Tc, it merely is an experimental temperature without any extra-thermodynamic meaning.
- Soto, Victor H.,Vázquez-Tato, M. Pilar,Meijide, Francisco,Alvarado, María José,Seijas, Julio A.,De Frutos, Santiago,Lomonte, Bruno,Vázquez Tato, José
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- Di(1H,1H,2H,2H-perfluorooctyl)-dibenzo-18-crown-6: A "light fluorous" recyclable phase transfer catalyst
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A series of dibenzo-18-crown-6 lariat ethers containing two C 7H15 (11), (CH2)2C6F 13 (14), (CH2)2C8F17 (15), NHC7H15 (18) and NHCH2C6F 13 (19) sidearms were prepared and the single crystal X-ray structure of cis-4,4′-di(1H,1H,2H,2H-perfluorodecyl)-dibenzo-18-crown-6 (15a) is reported. The "light fluorous" dibenzo-18-crown-6 ether (14) has emerged as a stable and robust PTC catalyst, which can be recycled efficiently by fluorous solid-phase extraction, and gives better PTC catalytic activity compared to the parent, non-fluorinated PTC catalyst, dibenzo-18-crown-6, and the alkylated derivative (11) in aliphatic and aromatic nucleophilic substitutions.
- Gourdet, Benoit,Singh, Kuldip,Stuart, Alison M.,Vidal, José A.
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- Cooperation between catalytic sites on a bicipital supported phosphonium phase-transfer catalyst
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A novel bicipital tetraarylphosphonium salt grafted to silica gel is prepared and characterised, and gives unusually high catalytic rate enhancements in some nucleophilic substitution reactions, which suggest cooperation between the neighbouring phosphonium centres.
- Clark, James H.,Tavener, Stewart J.,Barlow, Simon J.
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- Contra-thermodynamic Olefin Isomerization by Chain-Walking Hydroboration and Dehydroboration
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We report a dehydroboration process that can be coupled with chain-walking hydroboration to create a one-pot, contra-thermodynamic, short-or long-range isomerization of internal olefins to terminal olefins. This dehydroboration occurs by a sequence comprising activation with a nucleophile, iodination, and base-promoted elimination. The isomerization proceeds at room temperature without the need for a fluoride base, and the substrate scope of this isomerization is expanded over those of previous isomerizations we have reported with silanes.
- Bloomer, Brandon,Butcher, Trevor W.,Ciccia, Nicodemo R.,Conk, Richard J.,Hanna, Steven,Hartwig, John F.
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supporting information
p. 1005 - 1010
(2022/02/10)
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- Radical induced disproportionation of alcohols assisted by iodide under acidic conditions
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The disproportionation of alcohols without an additional reductant and oxidant to simultaneously form alkanes and aldehydes/ketones represents an atom-economical transformation. However, only limited methodologies have been reported, and they suffer from a narrow substrate scope or harsh reaction conditions. Herein, we report that alcohol disproportionation can proceed with high efficiency catalyzed by iodide under acidic conditions. This method exhibits high functional group tolerance including aryl alcohol derivatives with both electron-withdrawing and electron-donating groups, furan ring alcohol derivatives, allyl alcohol derivatives, and dihydric alcohols. Under the optimized reaction conditions, a 49% yield of 5-methyl furfural and a 49% yield of 2,5-diformylfuran were obtained simultaneously from 5-hydroxymethylfurfural. An initial mechanistic study suggested that the hydrogen transfer during this redox disproportionation occurred through the inter-transformation of HI and I2. Radical intermediates were involved during this reaction.
- Huang, Yang,Jiang, Haiwei,Li, Teng,Peng, Yang,Rong, Nianxin,Shi, Hexian,Yang, Weiran
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supporting information
p. 8108 - 8115
(2021/10/29)
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- A rings-in-pores net: Crown ether-based covalent organic frameworks for phase-transfer catalysis
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We herein present a new family of crown ether-based covalent organic frameworks (CE-COFs) for the first time. The CE-COFs show excellent phase-transfer catalytic performance in various nucleophilic substitution reactions.
- Guo, Wen-Di,Hu, Bingwen,Jiang, Wei-Ling,Lou, Xiaobing,Ma, De-Li,Qi, Qiao-Yan,Shen, Ji-Chuang,Shen, Ming,Yang, Hai-Bo,Zhao, Xin
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supporting information
p. 595 - 598
(2020/01/29)
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- Cuprous complex containing diphospho-ortho-carborane ligand as well as preparation method and application thereof (by machine translation)
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The method comprises the following steps, adding :1) solution to the ortho-carborane solution n - BuLi, reacting, at room temperature for 30 - 60min;2), adding, and reacting 1 - 3h;3) with high yield CuI, of the monovalent copper complex to react alcohol and iodide to synthesize the iodo-hydrocarbon 3 - 6h, and synthesizing the iodo-hydrocarbon; through post-treatment at room temperature for synthesizing the iodo-copper complex, by the following steps: reacting the alcohol with the iodide at room temperature and carrying out post-treatment to obtain the monovalent copper complex . The preparation method comprises the following steps: catalyzing alcohol and iodide to react with the iodide, to synthesize the iodo- hydrocarbyl complex; and the method comprises the following steps: catalyzing alcohol and iodide to react. (by machine translation)
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Paragraph 0047-0049; 0052-0056
(2020/05/02)
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- Grafted Polyethylene Glycol–Graphene Oxide as a Novel Triphase Catalyst for Carbenes and Nucleophilic Substitution Reactions
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Abstract: Separation and reusability had been main problems for the using of polyethylene glycol (PEG) as phase transfer catalysts (PTCs). To solve these problems, PEG was firstly and successfully grafted on graphene oxide (GO) using BF3·C2H5OC2H5 as Lewis acid catalyst. The solid GO-PEG composites were systemically investigated by characterization techniques (TG, FT-IR, XPS, ICP-AES etc.) and then applied to some carbenes and nucleophilic substitution reactions as novel triphase catalysts. As the results, GO-PEG showed not only equally excellent catalytic activity (≥ 93% yield of 7,7-dichlorobicyclo[4.1.0]heptane and iodooctane) but also incomparable reusability (≥ 85% yield of iodooctane after using for four times) in comparison with traditional PTCs (PEG). Graphic Abstract: [Figure not available: see fulltext.].
- Yang, Xiaohai,Zhai, Jie,Xu, Tongchun,Xue, Bing,Zhu, Jie,Li, Yongxin
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p. 2767 - 2775
(2019/06/17)
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- SN2 Reactions in Hydrocarbon Solvents Using Ammonium-Terminated Polyisobutylene Oligomers as Phase-Solubilizing Agents and Catalysts
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Although SN2 reactions have been thoroughly studied in polar aprotic and protic solvents, not many studies have been done to study the rate of SN2 reaction in nonpolar solvents like alkanes due to the insolubility of anionic nucleophiles in these solvents. In this study, we investigated the use of N,N-diethyl-N-methylammonium-terminated polyisobutylene oligomers as phase-solubilizing agents for nucleophilic anions that could react with hydrocarbon-soluble substrates in alkanes. The results of these kinetic studies showed alkanes were comparable to MeCN as solvents in many reactions. Based on these studies, we developed a solid/liquid catalytic process using insoluble alkali metal carboxylate salts and a recyclable soluble polyisobutylene-bound catalyst that can be used to carry out SN2 reactions both in heptane and in hydrocarbon oligomeric solvents known as poly(α-olefins) (PAOs).
- Samunual, Peerada,Bergbreiter, David E.
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p. 11101 - 11107
(2018/08/06)
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- Rhodium-Catalyzed Generation of Anhydrous Hydrogen Iodide: An Effective Method for the Preparation of Iodoalkanes
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The preparation of anhydrous hydrogen iodide directly from molecular hydrogen and iodine using a rhodium catalyst is reported for the first time. The anhydrous hydrogen iodide generated was proven to be highly active in the transformations of alkenes, phenyl aldehydes, alcohols, and cyclic ethers to the corresponding iodoalkanes. Therefore, the present methodology not only has provided convenient access to anhydrous hydrogen iodide but also offers a practical preparation method for various iodoalkanes in excellent atom economy.
- Zeng, Chaoyuan,Shen, Guoli,Yang, Fan,Chen, Jingchao,Zhang, Xuexin,Gu, Cuiping,Zhou, Yongyun,Fan, Baomin
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supporting information
p. 6859 - 6862
(2018/10/25)
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- Ferric(III) Chloride Catalyzed Halogenation Reaction of Alcohols and Carboxylic Acids Using α,α-Dichlorodiphenylmethane
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A new method for chlorination of alcohols and carboxylic acids, using α,α-dichlorodiphenylmethane as the chlorinating agent and FeCl3 as the catalyst, was developed. The method enables conversions of various alcohols and carboxylic acids to their corresponding alkyl and acyl chlorides in high yields under mild conditions. Particulary interesting is the observation that the respective alkyl bromides and iodides can be generated from alcohols when either LiBr or LiI are present in the reaction mixtures.
- Lee, Chang-Hee,Lee, Soo-Min,Min, Byul-Hana,Kim, Dong-Su,Jun, Chul-Ho
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supporting information
p. 2468 - 2471
(2018/04/25)
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- Electron-Transfer-Induced Intramolecular Heck Carbonylation Reactions Leading to Benzolactones and Benzolactams
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A metal-catalyst-free intramolecular Heck carbonylation reaction of benzyl alcohols and benzyl amines with carbon monoxide under heating at 250 °C affords the corresponding benzolactones and benzolactams in good to excellent yields. A hybrid radical/ionic chain mechanism, involving electron transfer from radical anions generated by nucleophilic attack of alcohols or amines on intermediate acyl radicals, is proposed.
- Fukuyama, Takahide,Bando, Takanobu,Ryu, Ilhyong
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p. 3015 - 3021
(2018/06/08)
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- Catalytic halodefluorination of aliphatic carbon-fluorine bonds
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A variety of halosilanes, in conjunction with aluminum catalysts, convert fluorocarbons into higher halocarbons. Bromination and iodination of fluorocarbons are more effective than chlorination in terms of yield and activity. The mechanism for the reaction is investigated utilizing experimental and computational evidence and preliminary results suggest an alternate mechanism to that reported for the related hydrodefluorination reaction.
- Goh, Kelvin K.K.,Sinha, Arup,Fraser, Craig,Young, Rowan D.
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p. 42708 - 42712
(2016/05/19)
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- Configurational Assignment of ‘Cryptochiral’ 10-Hydroxystearic Acid Through an Asymmetric Catalytic Synthesis
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An asymmetric catalytic total synthesis of (S)-10-hydroxystearic acid (1) for comparison of its absolute configuration to that of samples obtained by fermentative hydration of oleic acid is reported. The synthesis involves two catalytic key-steps, namely Ru-catalyzed anti-Markovnikov hydration of 9-decynoic acid (7) to 10-oxodecanoic acid (5), followed by titanium-mediated asymmetric catalytic addition of dioctylzinc (25) to 5 in presence of the chiral ligand N,N’-((1R,2R)-cyclohexane-1,2-diyl)bis(1,1,1-trifluoromethanesulfonamide) (6). The synthesis is short and efficient and avoids use of protecting groups. Ozonolysis of 10-undecynoic acid (9) to 5 provides an alternative entry point into the synthetic route. The double dehydrobromination of (ω,ω-1)-dibromoalkanoic acids to ω-alkynoic acids under a variety of conditions was investigated with 10,11-dibromoundecanoic acid (11) as model substrate and using qNMR to quantify all reaction products. The synthetic approaches presented here have the potential to be generalized to the asymmetric catalytic synthesis of a variety of n-hydroxy-fatty acids.
- Brunner, Andreas,Hintermann, Lukas
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p. 928 - 943
(2016/12/09)
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- A mild and highly chemoselective iodination of alcohol using polymer supported DMAP
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The synthesis of organic compounds using polymer supported catalysts and reagents, where the required product is always in solution, has been of great interest in recent years, both in industries and academia especially in pharmaceutical research. Here, a simple and efficient method for conversion of alcohols into their iodides in high yield using polymer supported 4-(Dimethylamino)pyridine (DMAP) is described. Polymer supported DMAP is used in catalytic amount and is recovered and reused several times. Additionally, this method is highly chemoselective. [Figure not available: see fulltext.]
- Das, Diparjun,H Anal, Jasha Momo,Rokhum, Lalthazuala
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p. 1695 - 1701
(2017/03/08)
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- One-Pot Transformation of Aliphatic Carboxylic Acids into N-Alkylsuccin-imides with NIS and NCS/NaI
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Primary aliphatic carboxylic acids were treated with N-iodosuccinimide (NIS) in 1,2-dichloroethane to form the corresponding alkyl iodides under warming conditions. Based on these results, those aliphatic carboxylic acids were treated with NIS, followed by the reaction with K2CO3to give the corresponding N-alkylsuccinimides in good yields in one pot. Moreover, those aliphatic carboxylic acids were treated with N-chlorosuccinimide (NCS) and NaI, followed by the reaction with K2CO3to provide the corresponding N-alkylsuccinimides in good to moderate yields in one pot. By using the present method, successive treatment of primary aliphatic carboxylic acids (10 mmol) with NIS, K2CO3, and then hydrazine provided the corresponding decarboxylated primary amines in good yield.
- Nakai, Yuhta,Moriyama, Katsuhiko,Togo, Hideo
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p. 768 - 772
(2017/01/18)
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- Halogen Exchange Reaction of Aliphatic Fluorine Compounds with Organic Halides as Halogen Source
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The halogen exchange reaction of aliphatic fluorine compounds with organic halides as the halogen source was achieved. Treatment of alkyl fluorides (primary, secondary, or tertiary fluorides) with a catalytic amount of titanocene dihalides, trialkyl aluminum, and polyhalomethanes (chloro or bromo methanes) as the halogen source gave the corresponding alkyl halides in excellent yields under mild conditions. In the case of a fluorine/iodine exchange, no titanocene catalyst is needed. Only C-F bonds are selectively activated under these conditions, whereas alkyl chlorides, bromides, and iodides are tolerant to these reactions.
- Mizukami, Yuki,Song, Zhiyi,Takahashi, Tamotsu
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supporting information
p. 5942 - 5945
(2016/01/09)
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- Application of "click" chemistry in solid phase synthesis of alkyl halides
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A convenient and highly selective microwave assisted procedure for the conversion of allylic, benzylic and aliphatic alcohols to their corresponding halides using polymer-bound triphenylphosphine and iodine is presented. In case of symmetrical diols, mono-iodination product is obtained in very high yield. Additionally, highly regioselective behavior is observed in our procedure. Simplicity in operation, no column chromatography required for the purification of the products, recyclability of the reagents used, short reaction times and good to excellent yields are the advantages of our protocol. Most functional groups remain unaffected under our reaction condition.
- Das, Diparjun,Chanda, Tridib,Rokhum, Lalthazuala
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p. 775 - 783
(2016/01/20)
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- A powerful tool for acid catalyzed organic addition and substitution reactions
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A novel green chemistry tool for acid catalyzed reactions has been developed. The multipurpose tool is based on the ability of dry solid materials to donate protons (H+) to starting materials combined with the simultaneous use of a nucleophile (e.g. NaI). The methods enable the following reactions to be conducted at 20-50 °C: selective addition of iodine or alcohols to more substituted carbon in R2CCH2 systems (R ≠ H), esterification reactions, e.g. free fatty acids with methanol, and at higher temperatures, (60-100 °C): esterification of free fatty acids with hindered alcohols (isopropanol), addition of iodine to CC bonds, opening of oxygen(s) containing heterocyclic rings, selective substitution of primary OH groups to iodine in the presence of other functional groups or secondary alcohol groups, esterification of alcohols with nitriles (R-CN), transesterification of fatty acid triglycerides to biodiesel and selective derivatization of primary hydroxyl groups (-CH2OH) over secondary moieties of sugars without any protection. Most of the reactions were also performed by a re-used Dowex cation exchange resin.
- Turhanen, Petri A.,Veps?l?inen, Jouko J.
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p. 26218 - 26222
(2015/10/20)
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- Solvent-free, microwave-assisted conversion of tosylates into iodides
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A highly efficient method for the conversion of primary tosylates into the corresponding iodides is outlined. The method involves heating a neat mixture of the tosylate and solid sodium iodide in a microwave cavity. Reaction times are short, usually about 60 minutes, delivering high yields. This procedure is especially useful for the in situ generation of volatile primary iodides, and for most of the primary iodides, the crude product is sufficiently pure.
- Cao, Jia,Perlmutter, Patrick
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p. 1360 - 1361
(2014/11/07)
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- Ionic liquid-induced conversion of methoxymethyl-protected alcohols into nitriles and iodides using [Hmim][NO3]
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This Letter reports a one-pot efficient conversion of methoxymethyl-ethers into their corresponding nitriles and iodides using the ionic liquid, 1-methyl-3H-imidazolium nitrate ([Hmim][NO3]) under microwave irradiation. A variety of products were prepared in high yields using this method.
- Noei, Jalil,Mirjafari, Arsalan
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supporting information
p. 4424 - 4426
(2014/08/05)
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- Microwave assisted synthesis of spirocyclic pyrrolidines - σ1 receptor ligands with modified benzene-N-distance
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Two series of σ1 ligands with a spiro[[2]benzopyran-1, 3′-pyrrolidine] (3) and a spiro[[2]benzofuran-1,3′-pyrrolidine] (4) framework were synthesized and pharmacologically evaluated. Several reaction steps were considerably improved by microwave irradiation. The σ1 affinity of the spirocyclic ligands correlates nicely with the benzene-N-distance, i.e. 2 1 affinity of both compound classes could be increased with large N-substituents (e.g. 2-phenylethyl, octyl). Nevertheless the benzyl derivative 4a represents the most promising σ1 ligand (Ki = 25 nM) due to its high selectivity against the σ2 subtype (>40-fold), the NMDA receptor and 5-HT6 and 5-HT7 receptors. Moreover, 4a did not inhibit the hERG channel in the heart.
- Jasper, Annemarie,Schepmann, Dirk,Lehmkuhl, Kirstin,Vela, Jose Miguel,Buschmann, Helmut,Holenz, Joerg,Wuensch, Bernhard
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experimental part
p. 327 - 336
(2012/08/13)
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- A facile and green protocol for nucleophilic substitution reactions of sulfonate esters by recyclable ionic liquids [bmim][X]
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Ionic liquids [bmim][X] (X = Cl, Br, I, OAc, SCN) are highly efficient reagents for nucleophilic substitution reactions of sulfonate esters derived from primary and secondary alcohols. The counter anions (X-) of the ionic liquids, [bmim][X], effectively replace the sufonates affording the corresponding substitution products such as alkyl halides, acetates, and thiocyanides in excellent yields. The newly developed protocol is very environmentally attractive because the reactions use stoichiometric amounts of ionic liquids as sole reagents in most cases and do not require additional solvents, any other activating reagents, non-conventional equipment, or special precautions. Moreover, these ionic liquids can be readily recycled without loss of reactivity, making the whole process greener.
- Liu, Yajun,Xu, Yongnan,Jung, Sun Ho,Chae, Junghyun
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p. 2692 - 2698,7
(2012/12/12)
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- A facile and green protocol for nucleophilic substitution reactions of sulfonate esters by recyclable ionic liquids [bmim][X]
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Ionic liquids [bmim][X] (X = Cl, Br, I, OAc, SCN) are highly efficient reagents for nucleophilic substitution reactions of sulfonate esters derived from primary and secondary alcohols. The counter anions (X-) of the ionic liquids, [bmim][X], effectively replace the sufonates affording the corresponding substitution products such as alkyl halides, acetates, and thiocyanides in excellent yields. The newly developed protocol is very environmentally attractive because the reactions use stoichiometric amounts of ionic liquids as sole reagents in most cases and do not require additional solvents, any other activating reagents, non-conventional equipment, or special precautions. Moreover, these ionic liquids can be readily recycled without loss of reactivity, making the whole process greener. Georg Thieme Verlag KG Stuttgart · New York.
- Liu, Yajun,Xu, Yongnan,Jung, Sun Ho,Chae, Junghyun
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p. 2692 - 2698
(2013/01/15)
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- Efficient organic transformations mediated by ZrOCl28H 2O in Water
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Operationally simple and environmentally benign methods for some organic transformations comprising reductive coupling of sulfonyl chlorides, chemoselective deoxygenation of sulfoxides, and halogenation of alcohols mediated by ZrOCl28H2O/MX in water have been developed.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Heidari, Mahdieh
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experimental part
p. 1470 - 1482
(2011/10/05)
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- Cobalt-catalyzed photopromoted carbonylation of chloroalkanes in the presence of KI
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The photopromoted carbonylation of chloroalkanes with carbon monoxide catalyzed by cobalt compounds [Co(OAc)2, CoCl2] in the presence of KI was carried out under ambient conditions. The results revealed that the catalytic activity of Co(OAc)2 was higher than that of CoCl2. A basic additive NaOAc was beneficial to the reaction. Interestingly, with NaOAc as an additive, Co(OAc)2 and CoCl2 exhibited similar catalytic activity. Preliminary work showed that the role of iodide ion was initially to form active iodoalkanes via substituting chloride ion in chloroalkanes in situ, and then, the carbonylation of iodoalkanes proceeded under irradiation.
- Jia, Ying Ping,Cui, Ying Na,Yin, Jing Mei,Zhou, Guang Yun,Li, Shen Min,Gao, Da Bin,Wang, Xiang Sheng
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scheme or table
p. 1033 - 1036
(2011/10/05)
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- H3PW12O40-[bmim][FeCl4]: A novel and green catalyst-medium system for microwave-promoted selective interconversion of alkoxymethyl ethers into their corresponding nitriles, bromides and iodides
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In the present work, the catalytic activity of 12-tungstophosphoric acid immobilized on [bmim][FeCl4] ionic liquid as a highly efficient and eco-friendly catalytic system for rapid and chemoselective direct conversion of MOM- or EOM-ethers into their corresponding nitriles, bromides and iodides under microwave irradiation is reported. In these reactions, the products are obtained in high yields. The catalyst exhibited remarkable reactivity and was reused several times.
- Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiolah,Mirjafari, Arsalan
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experimental part
p. 1468 - 1473
(2011/10/09)
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- Microwave-promoted, one-pot conversion of alkoxymethylated protected alcohols into their corresponding nitriles, bromides, and iodides using [bmim][InCl4] as a green catalyst
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The Lewis acid room temperature ionic liquid, [bmim][InCl4], was found to be an efficient and green catalyst for the highly chemoselective and one-pot conversion of MOM- or EOM-ethers into their corresponding nitriles, bromides, and iodides under microwave irradiation. The procedures are simple, rapid, and high yielding. The catalyst exhibited a remarkable reactivity and is reusable.
- Mirjafari, Arsalan,Mohammadpoor-Baltork, Iraj,Moghadam, Majid,Tangestaninejad, Shahram,Mirkhani, Valiollah,Khosropour, Ahmad Reza
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supporting information; experimental part
p. 3274 - 3276
(2010/07/18)
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- Mono-ionizable calix[4]arene-benzocrown-6 ligands in 1,3-alternate conformations: synthesis, structure and silver(I) extraction
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Two series of novel mono-ionizable calix[4]arene-benzocrown-6 ligands in 1,3-alternate conformations are synthesized. In one series, the proton-ionizable group (PIG) is attached to the para position of one aromatic ring in the calixarene framework, thereby positioning it over the polyether ring cavity. In the other series, the PIG is a substituent on the benzo group in the polyether ring. This orients the PIG away from the crown ether cavity. In addition to carboxylic acid functions, the PIGs include N-(X)sulfonyl carboxamide groups. With X group variation from methyl to phenyl to 4-nitrophenyl to trifluoromethyl, the acidity of the PIG is 'tuned'. Solvent extraction of Ag+ from aqueous solutions into chloroform is used to probe the influence of structural variation within the mono-ionizable calixcrown ligand on metal ion extraction efficiency, including the identity and acidity of the PIG and its orientation with respect to the polyether ring.
- Surowiec, Malgorzata,Custelcean, Radu,Surowiec, Kazmiriez,Bartsch, Richard A.
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supporting information; experimental part
p. 7777 - 7783
(2009/12/24)
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- Cerulenin analogues as inhibitors of efflux pumps in drug-resistant candida albicans
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Overexpression of the ABC transporters Cdrl and Cdr2 or the major facilitator Mdrl causes multidrug resistance in the human fungal pathogen Candida albicans. The fatty acid synthesis inhibitor cerulenin and the structurally unrelated Golgi transport inhibitor brefeldin A are substrates for both types of efflux pumps in Candida albicans. In an effort to overcome efflux pump-mediated drug resistance in Candida albicans, cerulenin analogues were generated using a variety of synthesis pathways. The so obtained cerulenin derivatives were tested on multidrug-resistant Candida albicans isolates which constitutively overexpress either Mdr1 or Cdr1 and Cdr2. Some of these compounds were found to decrease Mdr1-mediated resistance to brefeldin A up to eight-fold compared to the control. 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
- Diwischek, Florian,Morschhae, Joachim,Holzgrabe, Ulrike
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experimental part
p. 150 - 164
(2009/05/07)
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- Iron-catalyzed cross-coupling of alkyl sulfonates with arylzinc reagents
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Iron-catalyzed cross-coupling reactions of primary and secondary alkyl sulfonates with arylzinc reagents proceed smoothly In the presence of excess TMEDA and a concomitant magnesium salt. The arylzinc reagents are prepared from the corresponding aryllithium or magnesium reagents with ZnI2. The In situ formation of alkyl Iodides and consecutive rapid cross-coupling avoids discrete preparation of the unstable secondary alkyl halides and also achieves high product selectivity.
- Ito, Shingo,Fujiwara, Yu-Ichi,Nakamura, Eiichi,Nakamura, Masaharu
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supporting information; experimental part
p. 4306 - 4309
(2009/12/26)
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- Perfluorocarbon soluble crown ethers as phase transfer catalysts
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Fluorous derivatives of dibenzo-18-crown-6 ether were readily prepared by means of metal-catalyzed cross-coupling reactions, and then successfully applied as catalysts in representative solid-liquid phase transfer catalysis (PTC) reactions, which were performed in standard organic solvents, such as chlorobenzene and toluene, and also in fluorous solvents, such as perfluoro-1,3-dimethylcyclohexane (PFDMC). It was clearly shown that properly designed fluoroponytailed crown ethers can promote the disintegration of the crystal lattice of alkali salts and transfer anions from the solid surface into an apolar, non-coordinating perfluorocarbon phase. Far from beinga simple chemical curiosity, this unprecedented observation has relevant implications in the design of PTC scenarios of wide applicability. This new paradigm represents an advance in crown ether chemistry, and their use as recyclable phase transfer catalysts.
- Pozzi, Gianluca,Quici, Silvio,Fish, Richard H.
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experimental part
p. 2425 - 2436
(2009/10/06)
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- Simple synthesis of fresh alkyl iodides using alcohols and hydriodic acid
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A simple synthesis of fresh alkyl iodides using alcohols and hydriodic acid (HI) is reported. The alkyl iodides were obtained in quick and easy work-up with good to excellent yields (66-94%) and very high purities (97-99%). Freshly prepared iodomethane and 1-iodobutane were applied to synthesize biologically relevant 3,7-dimethyladenine and 9-butyladenine, which were characterized thoroughly using 1D and 2D NMR, individually.
- Klein, Suzane M.,Zhang, Cungen,Jiang, Yu Lin
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p. 2638 - 2641
(2008/09/19)
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- New non-hydrolysing poly(oxyethylene) silicon compounds as ligands for phase-transfer catalysis
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The non-hydrolysing silicon-containing ligands have been synthesised via hydrosilylation and studied as catalysts for liquid-liquid and solid-liquid phase-transfer catalysis.
- Gierczyk, B?azej,Schroeder, Grzegorz
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- Reactivity of anionic nucleophiles in ionic liquids and molecular solvents
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The nucleophilic reactivity of a representative series of anions has been measured in [hmim][ClO4] 3i, [hm2im][ClO4] 3′i, and [hmim][PF6] 3l ILs in the reaction with n-alkyl methanesulfonates and compared with that found in common molecular solvents (MeOH, DMSO, PhCl). The reactivity is found to depend on both the imidazolium cation-anion interaction and the specific solvation by water present in the IL, the water playing the main effect, in particular with hydrophilic anions. Removal of the largest quantity of water remarkably increases the ion pair reactivity in the IL up to rate constant value k comparable with those obtained in DMSO and in low polarity media (PhCl).
- Betti, Cecilia,Landini, Dario,Maia, Angelamaria
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p. 1689 - 1695
(2008/09/18)
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- Conversion of (sp3)C-F bonds of alkyl fluorides to (sp 3)C-heteroatom (heteroatom = I, SR, SeR, TeR) bonds by the use of magnesium reagents having heteroatom substituents
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A convenient method for conversion of (sp3)C-F bonds to (sp 3)C-Z (Z = I, SR, SeR, TeR) bonds has been developed. The reaction proceeds at room temperature using magnesium salts (Z-MgX). SN2 mechanism for substitiution of primary alkyl fluorides with MgI2 in ether was supported by the inversion of the stereochemistry of the carbon connecting to F. Copyright
- Begum, Shameem Ara,Terao, Jun,Kambe, Nobuaki
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p. 196 - 197
(2008/02/03)
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- Perfluoroalkylated 4,13-diaza-18-crown-6 ethers: Synthesis, phase-transfer catalysis, and recycling studies
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(Chemical Equation Presented) A series of N,N′-dialkyl-4,13-diaza-18- crown-6 lariat ethers possessing two C8H17 (2), (CH 2)3C8F17 (3), (CH2) 3C10F21 (4), and (CH2) 2C8F17 (5) side arms were synthesized in good yields by N-alkylation of 4,13-diaza-18-crown-6. Potassium picrate could be extracted from an aqueous solution into an organic phase by all of the perfluoroalkylated macrocycles demonstrating their potential to be used as phase-transfer catalysts, and preliminary studies on a classical nucleophilic substitution established that they each gave higher catalytic activities under solid-liquid than under liquid-liquid phase-transfer conditions. The light fluorous macrocycles gave similar, if not better, catalytic activity compared to the parent, non-fluorinated phase-transfer catalyst 2 under solid-liquid conditions in conventional organic solvents in both an aliphatic and an aromatic nucleophilic substitution. N,N′-Bis(1H,1H,2H,2H,3H,3H-perfluoroundecyl)- 4,13-diaza-18-crown-6 (3) was recycled six times in the iodide displacement reaction of 1-bromooctane and four times in the fluoride displacement reaction of 2,4-dinitrochlorobenzene using fluorous solid-phase extraction without any loss in activity.
- Stuart, Alison M.,Vidal, Jose A.
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p. 3735 - 3740
(2008/02/03)
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- Magnetic nanoparticle-supported crown ethers
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Magnetic nanoparticle (MNP)-supported crown ethers were successfully prepared and evaluated as catalysts for solid-liquid phase-transfer reactions; the catalytic activities of the MNP-supported crown ethers were not inferior to those of non-supported crown ethers; after the reactions, the catalysts could be readily separated using an external magnet and reused without significant loss of catalytic efficiency. The Royal Society of Chemistry.
- Kawamura, Masato,Sato, Kazuhiko
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p. 3404 - 3405
(2008/02/13)
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- Magnetically separable phase-transfer catalysts
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Magnetic nanoparticles-supported quaternary ammonium and phosphonium salts were prepared and evaluated as phase-transfer catalysts. Some of them exhibited good activities that were comparable to that of tetra-n-butylammonium iodide. The catalysts were readily separated using an external magnet and reusable without significant loss of their catalytic efficiency. The Royal Society of Chemistry.
- Kawamura, Masato,Sato, Kazuhiko
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p. 4718 - 4719
(2007/10/03)
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- A new type of B-podand catalysts for solid-liquid phase transfer reactions
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Boron podands 1-4 (B-podands) were studied as strong complexing agents of alkali metal cations and very powerful catalysts in typical anion promoted reactions under solid-liquid conditions, even in chlorobenzene and acetonitrile. The results were comparable with the catalytic activity of classical phase transfer catalysts: crown ethers, polyethylene glycols (PEG) and previously studied Si-podands.
- ?eska, Bogus?awa,Pankiewicz, Rados?aw,Schroeder, Grzegorz,Maia, Angelamaria
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p. 5673 - 5676
(2007/10/03)
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- 4-Aminophenyldiphenylphosphinite (APDPP), a new heterogeneous and acid scavenger phosphinite - Conversion of alcohols, trimethylsilyl, and tetrahydropyranyl ethers to alkyl halides with halogens or N-halosuccinimides
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A new heterogeneous phosphinite, 4-aminophenyldiphenylphosphinite (APDPP), is prepared and used for the efficient conversion of alcohols, trimethylsilyl ethers, and tetrahydropyranyl ethers to their corresponding bromides, iodides, and chlorides in the presence of molecular halogens or N-halosuccinimides. The amino group in this phosphinite acts as an acid scavenger and removes the produced acid. A simple filtration easily removes the phosphinate by-product.
- Iranpoor, Nasser,Firouzabadi, Habib,Gholinejad, Mohammad
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p. 1006 - 1012
(2007/10/03)
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- Facile conversion of alcohols into their bromides and iodides by N-bromo and N-iodosaccharins/triphenylphosphine under neutral conditions
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N-Bromo and N-iodosaccharins in the presence of triphenylphosphine convert alcohols into the corresponding bromides and iodides in good to excellent yields at room temperature under neutral conditions.
- Firouzabadi, Habib,Iranpoor, Nasser,Ebrahimzadeh, Farzaneh
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p. 1771 - 1775
(2007/10/03)
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- A convenient and genuine equivalent to HZrCp2Cl generated in situ from ZrCp2Cl2-DIBAL-H
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Slow addition of 1 equiv of 1Bu2AlH to ZrCp 2Cl2 in THF provides a convenient route to either HZrCp2Cl-1Bu2AlCl (Reagent I) or HZrCp 2Cl (Reagents II and III). The latter represents a highly convenient route to genuine HZrCp2Cl, while Reagent I is useful for regio- and stereoselective conversion of 1- and 2-alkynes into (E)-1-iodo-1-alkenes and (E)-2-iodo-2-alkenes, respectively.
- Huang, Zhihong,Negishi, Ei-Ichi
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p. 3675 - 3678
(2007/10/03)
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- Catalytic activity and anion activation in SN2 reactions promoted by complexes of silicon polypodands. Comparison with traditional polyethers
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The catalytic activity of silicon polypodands was evaluated in anion-promoted reactions under solid-liquid phase-transfer catalysis (SL-PTC) conditions and compared with that exhibited by common PTC agents. Results showed that these many-armed ligands are
- Maia, Angelamaria,Landini, Dario,Betti, Cecilia,Leska, Boguslawa,Schroeder, Grzegorz
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p. 1195 - 1198
(2007/10/03)
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- Anion nucleophilicity in ionic liquids: A comparison with traditional molecular solvents of different polarity
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The nucleophilic reactivity of a homogeneous series of anions (halides, pseudohalides and organic anions) in the ionic liquids [hexmim] [ClO 4] and [hexmim] [PF6] has been measured in their reaction with n-alkyl methanesulfonates, and compared with that found in traditional molecular solvents of different polarity, that is, chlorobenzene, DMSO, and MeOH.
- Landini, Dario,Maia, Angelamaria
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p. 3961 - 3963
(2007/10/03)
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- A simple, efficient, and highly selective method for the iodination of alcohols using ZrCl4/NaI
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Iodination of primary, secondary, allylic, and benzylic alcohols giving their corresponding iodides was achieved with ZrCl4/NaI in anhydrous CH3CN with excellent yields and selectivities.
- Firouzabadi, Habib,Iranpoor, Nasser,Jafarpour, Maasoumeh
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p. 7451 - 7454
(2007/10/03)
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- Silicon polypodands: A new class of efficient solid-liquid phase-transfer catalysts
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Silicon polypodands 1-7 were found to be powerful complexing agents of alkali metal salts, even in low polarity media (chlorobenzene) and hence very efficient phase-transfer catalysts. Their catalytic activity was measured in typical anion-promoted reactions under solid-liquid phase-transfer catalysis (SL-PTC) conditions. It is mainly determined by the complexing ability of the ligand, increasing with the number of silicon atoms and binding sites. Comparison with traditional phase-transfer catalysts showed that these polypodands are better catalysts not only than open-chain PEG400Me2 and TRIDENT, but even than more sophisticated macrocyclic polyethers such as DCH18C6.
- Maia, Angelamaria,Landini, Dario,Leska, Boguslawa,Schroeder, Grzegorz
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p. 10111 - 10115
(2007/10/03)
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- Ionic liquid as an efficient promoting medium for two-phase nucleophilic displacement reactions
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The use of the room temperature ionic liquid (RTIL) 1-n-butyl-3-methylimidazolium hexafluorophosphate as an efficient catalyst and solvent for several representative nucleophilic substitution reactions under aqueous-RTIL phase transfer conditions was explored. Recycling and reuse of the reaction medium was demonstrated for the azide formation.
- Louren?o, Nuno M.T.,Afonso, Carlos A.M.
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p. 789 - 794
(2007/10/03)
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- Silicon polypodands: Powerful metal cation complexing agents and solid-liquid phase-transfer catalysts of new generation
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Silicon polypodands 5-7 are found to be powerful complexing agents of alkali metal salts in low polarity solvents and very efficient catalysts in anion-promoted reactions under solid-liquid PTC conditions. The catalytic activity is comparable with that of the cyclic polyether PHDB18C6 8.
- Maia, Angelamaria,Landini, Dario,Leska, Boguslawa,Schroeder, Grzegorz
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p. 4149 - 4151
(2007/10/03)
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- Highly efficient, general procedure for the preparation of alkylzinc reagents from unactivated alkyl bromides and chlorides
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(Matrix presented) Alkylzinc bromides have been efficiently prepared by the direct insertion of zinc metal (dust, powder, granule, shot), activated with 1-5 mol % I2, into alkyl bromides in a polar aprotic solvent. The zinc reagents thus formed undergo Ni- and Pd-catalyzed cross-coupling with aryl halides to produce functionalized alkylarenes in excellent yields.
- Huo, Shouquan
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p. 423 - 425
(2007/10/03)
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