- Controlled synthesis of polyphosphazenes with chain-capping agents
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N-alkyl phosphoranimines were synthesized via the Staudinger reaction of four different alkyl azides with tris(2,2,2-trifluoroethyl) phosphite. N-adamantyl, N-benzyl, N-t-butyl, and N-trityl phosphoranimines were thoroughly characterized and evaluated as
- Matyjaszewski, Krzysztof,Montague, Robert A.
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- Arsa-diazonium salts with an arsenic-nitrogen triple bond
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Arsenic triply bound: Arsa-diazonium salts containing a cation with an arsenic-nitrogen triple bond ([R-N≡As]+), which is stable at room temperature, are isolated and fully characterized for the first time. Analogous to the diazonium salts, ars
- Kuprat, Marcus,Schulz, Axel,Villinger, Alexander
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- Molecular batteries based on carbon - Carbon bond formation and cleavage in titanium and vanadium Schiff base complexes
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The reduction of titanium(III) and vanadium(III) salophen complexes led to the reductive coupling of imino groups in the ligands, and thus to the formation of C-C-bonded dimers which released electrons on subsequent cleavage of the C-C bond. On reduction
- Franceschi, Federico,Solari, Euro,Floriani, Carlo,Rosi, Marzio,Chiesi-Villa, Angiola,Rizzoli, Corrado
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- Facile Direct Coupling Reactions of MOM-protected Benzylic Alcohols Using Aluminum Chloride
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MOM group is one of the most commonly used protecting groups for alcohols. This study describes novel direct functionalization of the MOM-protected benzylic alcohols. Preparation of allylic compounds from benzyl MOM ethers was successfully achieved by utilization of allyltrimethylsilane and AlCl3. In addition, direct azidation of benzyl MOM ethers using TMSN3 was successful carried out under AlCl3-mediated reaction conditions. These results demonstrate that this novel synthetic procedure is a promising approach to direct functionalization of MOM-protected alcohols including allylation and azidation.
- Bui, Tien Tan,Kim, Hee-Kwon
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supporting information
p. 1195 - 1198
(2021/08/03)
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- Mangana(iii/iv)electro-catalyzed C(sp3)-H azidation
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Manganaelectro-catalyzed azidation of otherwise inert C(sp3)-H bonds was accomplished using most user-friendly sodium azide as the nitrogen-source. The operationally simple, resource-economic C-H azidation strategy was characterized by mild reaction conditions, no directing group, traceless electrons as the sole redox-reagent, Earth-abundant manganese as the catalyst, high functional-group compatibility and high chemoselectivity, setting the stage for late-stage azidation of bioactive compounds. Detailed mechanistic studies by experiment, spectrophotometry and cyclic voltammetry provided strong support for metal-catalyzed aliphatic radical formation, along with subsequent azidyl radical transfer within a manganese(iii/iv) manifold.
- Meyer, Tjark H.,Samanta, Ramesh C.,Del Vecchio, Antonio,Ackermann, Lutz
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p. 2890 - 2897
(2021/03/14)
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- Direct AlCl3-catalyzed transformation of benzyl THP ethers and allyl benzyl ethers
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THP and allyl groups are frequently used for the protection of alcohols. In this study, novel direct transformations of benzyl THP ethers and allyl benzyl ethers, protected forms of alcohols, are reported. TMSN3 and AlCl3 were employ
- Bui, Tien Tan,Kim, Hee-Kwon
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p. 388 - 397
(2020/10/15)
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- Iron-catalysed 1,2-aryl migration of tertiary azides
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1,2-Aryl migration of α,α-diaryl tertiary azides was achieved by using the catalytic system of FeCl2/N-heterocyclic carbene (NHC) SIPr·HCl. The reaction generated aniline products in good yields after one-pot reduction of the migration-resultant imines.
- Wei, Kaijie,Yang, Tonghao,Chen, Qing,Liang, Siyu,Yu, Wei
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supporting information
p. 11685 - 11688
(2020/10/19)
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- Manganese-Catalyzed Oxidative Azidation of C(sp3)-H Bonds under Electrophotocatalytic Conditions
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The selective installation of azide groups into C(sp3)-H bonds is a priority research topic in organic synthesis, particularly in pharmaceutical discovery and late-stage diversification. Herein, we demonstrate a generalized manganese-catalyzed oxidative azidation methodology of C(sp3)-H bonds using nucleophilic NaN3 as an azide source under electrophotocatalytic conditions. This approach allows us to perform the reaction without the necessity of adding an excess of the substrate and successfully avoiding the use of stoichiometric chemical oxidants such as iodine(III) reagent or NFSI. A series of tertiary and secondary benzylic C(sp3)-H, aliphatic C(sp3)-H, and drug-molecule-based C(sp3)-H bonds in substrates are well tolerated under our protocol. The simultaneous gram-scale synthesis and the ease of transformation of azide to amine collectively advocate for the potential application in the preparative synthesis. Good reactivity of the tertiary benzylic C(sp3)-H bond and selectivity of the tertiary aliphatic C(sp3)-H bond in substrates to incorporate nitrogen-based functionality at the tertiary alkyl group also provide opportunities to manipulate numerous potential medicinal candidates. We anticipate our synthetic protocol, consisting of metal catalysis, electrochemistry, and photochemistry, would provide a new sustainable option to execute challenging organic synthetic transformations.
- Niu, Linbin,Jiang, Chongyu,Liang, Yuwei,Liu, Dingdong,Bu, Faxiang,Shi, Renyi,Chen, Hong,Chowdhury, Abhishek Dutta,Lei, Aiwen
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supporting information
p. 17693 - 17702
(2020/11/12)
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- Site-Selective Copper-Catalyzed Azidation of Benzylic C-H Bonds
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Site selectivity represents a key challenge for non-directed C-H functionalization, even when the C-H bond is intrinsically reactive. Here, we report a copper-catalyzed method for benzylic C-H azidation of diverse molecules. Experimental and density functional theory studies suggest the benzyl radical reacts with a CuII-azide species via a radical-polar crossover pathway. Comparison of this method with other C-H azidation methods highlights its unique site selectivity, and conversions of the benzyl azide products into amine, triazole, tetrazole, and pyrrole functional groups highlight the broad utility of this method for target molecule synthesis and medicinal chemistry.
- Suh, Sung-Eun,Chen, Si-Jie,Mandal, Mukunda,Guzei, Ilia A.,Cramer, Christopher J.,Stahl, Shannon S.
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supporting information
p. 11388 - 11393
(2020/07/21)
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- Functionalization of a Single C?F Bond of Trifluoromethylarenes Assisted by an ortho-Silyl Group Using a Trityl-Based All-in-One Reagent with Ytterbium Triflate Catalyst
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Catalytic thiolation and azidation of a single C?F bond of trifluoromethylarenes were achieved assisted by an ortho-silyl group with all-in-one reagents to generate a trityl cation and nucleophiles. The reactions catalyzed by ytterbium triflate efficientl
- Kim, Youngchan,Kanemoto, Kazuya,Shimomori, Ken,Hosoya, Takamitsu,Yoshida, Suguru
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supporting information
p. 6136 - 6140
(2020/05/20)
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- A Direct Br?nsted Acid-Catalyzed Azidation of Benzhydrols and Carbohydrates
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Benzhydryl alcohols were converted into their corresponding diarylazidomethane analogues using azidotrimethylsilane (TMSN3) in the presence of a catalytic amount of a Br?nsted acid HBF4·OEt2. The azidation reactions proceeded in high yields and demonstrated excellent functional group tolerance to electron-donating and electron-withdrawing substituents. In addition, a range of unprotected functional groups including amine, amide, aldehyde and alcohol were well-tolerated. Furthermore, this methodology was successfully applied to carbohydrates for the preparation of the corresponding azide derivatives.
- Regier, Jeffery,Maillet, Robert,Bolshan, Yuri
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p. 2390 - 2396
(2019/04/14)
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- A Bismuth–Arene σ-Complex – On the Edge of Menshutkin-Type Complexes
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Mes*N(SiMe3)BiCl2 (1, Mes* = 2,4,6-tri-tert-butylphenyl) can be referred to as a hidden iminobismuthane, Mes*N=BiCl, which was thought to be generated in-situ upon Me3SiCl elimination triggered by a Lewis acid such as GaCl
- Bresien, Jonas,Schulz, Axel,Thomas, Max,Villinger, Alexander
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supporting information
p. 1279 - 1287
(2019/02/19)
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- Recyclable zinc (II) ionic liquid catalyzed synthesis of azides by direct azidation of alcohols using trimethylsilylazide at room temperature
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A new efficient method has been reported for the synthesis of azides by direct azidation of alcohols with TMSN3 in presence of recyclable task specific ionic liquid (TSIL) [bmim]ZnCl3 as a catalyst in DCM at room temperature. Ionic liquid [bmim]ZnCl3 was synthesized under solvent free conditions and characterized by IR, 1H NMR, 13C NMR and HRMS. The Lewis acidity of catalyst was also examined using IR spectroscopy. The main features of this new methodology are high yields of products, recyclability of catalyst, scalability of reaction to gram scale and short reaction time.
- Singh, Ashima,Singh, Harjinder,Khurana
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supporting information
p. 2498 - 2502
(2017/05/31)
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- Direct Conversion of Aldehydes and Ketones into Azides by Sequential Nucleophilic Addition and Substitution
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This report describes the direct conversion of aldehydes and ketones into alkyl azides by the addition of common organometallic reagents and tandem conversion of the resulting alkoxides without isolation of the intermediate alcohols. A wide range of aldehydes and organometallic reagents (R–Li or R–MgX) are suitable participants in this process. Additional reaction telescoping beyond azide formation is demonstrated.
- Goswami, Pratik P.,Suding, Victoria P.,Carlson, Angela S.,Topczewski, Joseph J.
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supporting information
p. 4805 - 4809
(2016/10/13)
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- A combination of trimethylsilyl chloride and hydrous natural montmorillonite clay: An efficient solid acid catalyst for the azidation of benzylic and allylic alcohols with trimethylsilyl azide
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We present a new procedure to convert in situ natural montmorillonite clay into a partially acidified one using a catalytic amount of trimethylsilyl chloride and trace water. We demonstrate that the acidic montmorillonite can catalyze the direct azidation
- Tandiary, Michael A.,Masui, Yoichi,Onaka, Makoto
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p. 15736 - 15739
(2015/02/19)
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- Synthesis and structure of tritylium salts
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Several tritylium compounds [Ph3C][A] have been isolated by salt metathesis or halide abstraction reactions starting from Ph3C-X (X = halogen) and Lewis acids in good yields (A = BF4, BCl4, AlCl4, GaCl4, PF6, AsF6, SbF6, SbCl6, CHB11H5Cl6, CHB11Cl11, CHB11H5Br6, CF3COO, CF3SO3, N3). The structures of 15 tritylium salts bearing different types of weakly coordinating anions (A-) have been determined. The structures are discussed on the basis of ion pairing versus covalent bond formation and solid-state interactions in comparison with gas-phase data.
- Hinz, Alexander,Labbow, René,Rei?, Fabian,Schulz, Axel,Sievert, Katharina,Villinger, Alexander
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p. 1641 - 1650
(2015/10/28)
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- Chemoselective and direct functionalization of methyl benzyl ethers and unsymmetrical dibenzyl ethers by using iron trichloride
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Methyl and benzyl ethers are widely utilized as protected alcohols due to their chemical stability, such as the low reactivity of the methoxy and benzyloxy groups as leaving groups under nucleophilic conditions. We have established the direct azidation of chemically stable methyl and benzyl ethers derived from secondary and tertiary benzyl alcohols. The present azidation chemoselectively proceeds at the secondary or tertiary benzylic positions of methyl benzyl ethers or unsymmetrical dibenzyl ethers and is also applicable to direct allylation, alkynylation, and cyanation reactions, as well as the azidation. The present methodologies provide not only a novel chemoselectivity but also the advantage of shortened synthetic steps, due to the direct process without the deprotection of the methyl and benzyl ethers. Ethers exchanged: Methyl and benzyl ethers are chemically stable and generally tolerant under nucleophilic substitution conditions. Iron-catalyzed direct functionalizations (e.g., azidation, allylation, alkynylation, and cyanation) of methyl and benzyl ethers derived from secondary and tertiary benzyl alcohols were established with excellent regioselectivities (see scheme; PG: protecting group; Bn: benzyl; Nu: nucleophile; TMS: trimethylsilyl). Copyright
- Sawama, Yoshinari,Goto, Ryota,Nagata, Saori,Shishido, Yuko,Monguchi, Yasunari,Sajiki, Hironao
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supporting information
p. 2631 - 2636
(2014/03/21)
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- A reagent for safe and efficient diazo-transfer to primary amines: 2-azido-1,3-dimethylimidazolinium hexafluorophosphate
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Organic azides were prepared from primary amines in high yields by a metal free diazo-transfer reaction using 2-azido-1,3-dimethylimidazolinium hexafluorophosphate (ADMP), which is safe and stable crystalline. The choice of base was important in the diazo-transfer reaction. In general, 4-(N,N-dimethyl)aminopyridine (DMAP) was efficient, but a stronger base such as alkylamine or DBU was more appropriate for the reaction of nucleophilic primary amines. X-ray single crystal structural analysis and geometry optimization using density functional theory (B3LYP/6-31G**) were conducted to study the ADMP structure, and the diazo-transfer reaction mechanism was explained with the help of the results of these analyses. the Partner Organisations 2014.
- Kitamura, Mitsuru,Kato, So,Yano, Masakazu,Tashiro, Norifumi,Shiratake, Yuichiro,Sando, Mitsuyoshi,Okauchi, Tatsuo
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p. 4397 - 4406
(2014/06/23)
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- Direct synthesis of organic azides from alcohols using 2-azido-1,3- dimethylimidazolinium hexafluorophosphate
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Direct synthesis of organic azides from alcohols was developed. Azide transfer of 2-azido-1,3-dimethylimidazolinium hexafluorophosphate (ADMP) to alcohols proceeds to give the corresponding azides under mild reaction conditions, which were easily isolated because the byproducts are highly soluble in water. Georg Thieme Verlag Stuttgart · New York.
- Kitamura, Mitsuru,Koga, Tatsuya,Yano, Masakazu,Okauchi, Tatsuo
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experimental part
p. 1335 - 1338
(2012/07/13)
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- Direct synthesis of organic azides from primary amines with 2-azido-1,3-dimethylimidazolinium hexafluorophosphate
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Organic azides were prepared from primary amines in high yields by metal-free diazo transfer with 2-azido-1,3-dimethylimidazolinium hexafluorophosphate, which is a stable, crystalline solid that is easy to handle. Organic azides were prepared from primary
- Kitamura, Mitsuru,Yano, Masakazu,Tashiro, Norifumi,Miyagawa, Satoshi,Sando, Mitsuyoshi,Okauchi, Tatsuo
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experimental part
p. 458 - 462
(2011/03/18)
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- Conversion of alkenes and alcohols to azides over zeolite-supported sodium azide
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Zeolite-supported sodium azide reagents are versatile catalysts for the conversion of various alkenes and alcohols to the corresponding azides in good yield under mild conditions.
- Sreekumar,Padmakumar,Rugmini
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p. 1133 - 1134
(2007/10/03)
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- Reactivities of triarylmethyl and diarylmethyl cations with azide ion investigated by laser flash photolysis. Diffusion-controlled reactions
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By use of the technique of laser flash photolysis, rate constants kAz and ks have been directly measured for the reactions at 20 °C in acetonitrile-water (AN-W) solutions of varying composition of 18 triarylmethyl and 10 diarylmethyl cations with azide and solvent. The cations have ks that depend on substituent and vary from ~101 to ~107 s-1. For the more stable ions kAz also varies, increasing with decreased electron donation and also increasing by as much as 103 with increasing acetonitrile content. For less stable cations, however, the rate constant becomes independent of substituent. The break occurs when ks has reached ~105 s-1. The limiting rate constants have magnitudes in the vicinity of 1010 M-1 s-1; these do depend on solvent and type of cation, with diarylmethyl cations reacting at the limit 1.6 ± 0.2 times faster than triarylmethyl. The data can be fit by a model where there is diffusional encounter of the cation and azide to form an ion pair, with the combination within the ion pair rate-limiting for the more stable cations and the diffusion step rate-limiting for the less stable ones. The limiting rate constants represent the latter, diffusional encounter of the cation and azide. The Debye-Smoluchowski equation for diffusion-controlled reactions predicts rate constants that are larger than observed by factors of 2-2.5 for diarylmethyl and 4 for triarylmethyl. Deviations can be attributed to nonproductive encounters where the anion has approached the cation in the plane of one of the rings and thus cannot form a proper reacting configuration. The difference between the two types of cations is explained by the greater difficulty of achieving this configuration with the more sterically congested triarylmethyl cation. Ratios kAz/ks obtained from product analysis (competition kinetics) have previously been found to show adherence to the reactivity-selectivity principle. This has been interpreted (Rappoport, Jencks) in terms of the reaction with azide having reached the diffusion limit. The directly measured kAz establish that this is indeed the case. This study also validates the use of azide as a "clock" (Jencks, Richard) for converting such ratios to absolute rate constants through use of a value of 5 × 109 M-1 s-1 for kAz. The directly measured diffusion-limited kAz are somewhat larger than this, but the differences are small, at most a factor of 4.
- McClelland, Robert A.,Kanagasabapathy,Banait, Narinder S.,Steenken, Steen
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p. 1009 - 1014
(2007/10/02)
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- Nucleophilic Substitution Reactions of Alkyl Halides By Using New Polymer-Supported Reagents Containing Hemin
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A new polymer reagent consisting of hemin, divinylbenzene, and 2-methyl-5-vinylpyridine was synthesized by suspension copolymerization.Substitution reactions of primary, secondary, and tertiary alkyl halides with the hemin copolymer combined with cyanide, azide, and thiocyanate ions were given satisfactory yields.This reaction mechanism was revealed to be a SNi type on the basis of stereochemical study.The hemin copolymer was not only a polymer-supported reagent with functional capabilities, but also served to separate the product from the reaction mixture.
- Saito, Kiyoshi,Harada, Kaoru
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p. 2562 - 2566
(2007/10/02)
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- Electrophilic Reactivity of the Triphenylmethyl Carbocation in Aqueous Solutions
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The triphenylmethyl (trityl) carbocation has been generated as a transient intermediate by laser flash photolysis of 1:2 (v/v) acetonitrile:water solutions of trityl acetate and trityl 4-cyanophenyl ether.Identification of the transient as the free carbocation in the ground state was based on its characteristic absorption spectrum and upon conductivity changes.Rate constants have been measured for the reaction of the cation in this solvent with a series of ionic and neutral nucleophiles.The solvent rate constant at 20 deg C is 1.5 x 105 s-1.Azide ions reacts at 4.1 x 109 M-1s-1; the directly measured azide:water ratio is compared to literature values determined by product analysis.Chloride ion reacts at 2 x 106 M-1 s-1; with bromide the equilibrium addition can be observed with k(comb) = 5 x 106 M-1 s-1 and k(ion) for Ph3CBr = 8 x 105 s-1.Rate constants do not adhere to the N+ relationship.This predicts a slope of unity in a plot of log k(Ph3C+) vs.N+, with the better nucleophiles reacting at the 1010 encounter-controlled limit.Azide is the only nucleophile of those studied to approach this.Sulfite and thiolate ions, which are better N+ nucleophiles, react at 2-3 x 108 M-1s-1, while amines react in the 106-107 M-1s-1 range.The plot vs.N+ has a slope of 0.3-0.4.One explanation is that rate constants for the better nucleophiles do level, but this occurs considerably below the 1010 limit.Alternatively, the less than unit slope is real and this more reactive cation, in contrast to more stable analogues, is exhibiting selectivity.
- McClelland, Robert A.,Banait, Narinder,Steenken, Steen
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p. 7023 - 7027
(2007/10/02)
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- Triphenyl-1,2,3-triazolyl-(1)-methanes, and compositions and methods for combating fungi and bacteria employing them
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Triphenyl-1,2,3-triazolyl-(1)-methanes of the formula STR1 in which X and Z each independently is hydrogen, alkyl, halogen, nitrile or thiocyano, and Y is hydrogen, halogen, alkyl, halogenoalkyl or nitro, Which possess fungicidal and bactericidal properti
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