- Regio- And stereoselective electrochemical synthesis of sulfonylated enethers from alkynes and sulfonyl hydrazides
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An electrooxidative direct difunctionalization of internal alkynes with sulfonyl hydrazides has been developed for the construction of sulfonated enethers. In this transformation, metal catalysts or stoichiometric amount of oxidants are not required and molecular nitrogen and hydrogen are the sole byproducts, providing a simple and green approach for preparing various sulfonyl tetrasubstituted alkenes. Notably, the protocol could be efficiently scaled up and the follow-up procedures of the corresponding functionalized alkenes demonstrate the practicality of the electrochemical synthesis.
- Du, Wu-Bo,Wang, Ning-Ning,Pan, Chao,Ni, Shao-Fei,Wen, Li-Rong,Li, Ming,Zhang, Lin-Bao
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supporting information
p. 2420 - 2426
(2021/04/07)
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- Method for the Preparation of Diamine Derivative
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The present invention relates to high yield. The present invention relates to a process for preparing high purity ethaboxate p - toluenesulphonate or hydrates thereof. To the present invention, generation of a dielectric toxic substance and a side reaction product can be suppressed, and high yield, high purity of edoxaba p - toluenesulphonate or a hydrate thereof can be advantageously used.
- -
-
Paragraph 0284-0288
(2021/03/23)
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- Regioselective Ring Expansion of 3-Ylideneoxindoles with Tosyldiazomethane (TsDAM): A Metal-Free and Greener Approach for the Synthesis of Pyrazolo-[1,5- c]quinazolines
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An efficient, metal-free approach to access pyrazolo-[1,5-c]quinazolines with 3-ylideneoxindoles and tosyldiazomethane (TsDAM) under mild aqueous reaction conditions has been developed and the solvent involvement in the present reaction has also been explored for the first time. This greener approach involves 1,3-dipolar cycloaddition, regioselective ring expansion, followed by the elimination of tosyl group with aqueous base in a single operation, and the product can be isolated in high purity without column chromatographic separation. The method is also compatible with a large variety of functional groups, providing good to excellent yields in water, thus resulting in a decrease of environmental impact in the pharmaceutical industry.
- Ramu, Gopathi,Tangella, Yellaiah,Ambala, Srinivas,Nagendra Babu, Bathini
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p. 5370 - 5378
(2020/05/19)
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- Visible-light-initiated regioselective sulfonylation/cyclization of 1,6-enynes under photocatalyst- And additive-free conditions
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Without employing any photocatalyst and additive, an economical, eco-friendly and practical strategy has been developed for the visible-light-initiated regioselective sulfonylation/cyclization of 1,6-enynes in a biomass-derived green solvent 2-methylTHF from easily accessible sulfonyl chlorides under open-air conditions at room temperature. Compared with conventional heating conditions, the use of a 3 W blue light-emitting diode (LED) or sunlight not only reduces energy consumption but also minimizes side reactions. This transformation has excellent regioselectivity, mild reaction conditions, broad substrate scope and ease of scale-up. Moreover, mechanistic studies indicated that a sulfonyl radical pathway was involved in this reaction.
- Meng, Xiao-Xiao,Kang, Qing-Qing,Zhang, Jun-Yao,Li, Qiang,Wei, Wen-Ting,He, Wei-Min
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p. 1388 - 1392
(2020/03/11)
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- Mild alkaline hydrolysis of hindered esters in non-aqueous solution
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Sterically hindered esters of carboxylic acids, which are considered very resistant to saponification, were rapidly and efficiently saponified in a non-aqueous medium using NaOH in MeOH/CH2Cl2 (1:9) at room temperature. Furthermore, this reaction protocol was extended and successfully applied to the hydrolysis of tosylates and N-tosyl indoles.
- Theodorou, Vassiliki,Alagiannis, Michalis,Ntemou, Nikoleta,Brentas, Alexios,Voulgari, Pinelopi,Polychronidou, Vasiliki,Gogou, Marina,Giannelos, Marios,Skobridis, Konstantinos
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p. 308 - 319
(2018/11/26)
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- Rapid transformation of sulfinate salts into sulfonates promoted by a hypervalent iodine(III) reagent
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An alternative method for forming sulfonates through hypervalent iodine(III) reagent-mediated oxidation of sodium sulfinates has been developed. This transformation involves trapping reactive sulfonium species using alcohols. With additional optimization of the reaction conditions, the method appears extendable to other nucleophiles such as electron-rich aromatic systems or cyclic ethers through a ring opening pathway.
- Deruer, Elsa,Hamel, Vincent,Blais, Samuel,Canesi, Sylvain
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supporting information
p. 1203 - 1207
(2018/06/04)
-
- Copper-Catalyzed Multicomponent Reaction of DABCO·(SO2)2, Alcohols, and Aryl Diazoniums for the Synthesis of Sulfonic Esters
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A Cu-catalyzed multicomponent cascade reaction of DABCO·(SO2)2 (DABSO), alcohol, and aryl diazonium tetrafluoroborate was developed which afforded sulfonic esters in moderate to good chemical yields. In this reaction, the SO2 surrogate DABSO was used for the first time in the synthesis of sulfonic aliphatic esters. This multicomponent reaction was carried out under mild conditions and tolerated a wide range of substrates, which provides a new and efficient strategy for the synthesis of sulfonic esters.
- Wang, Yang,Deng, Lingling,Deng, Yu,Han, Jianlin
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p. 4674 - 4680
(2018/04/26)
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- Method for synthesizing cis-tritosylate
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The invention discloses a method for preparing cis-tritosylate. The cis-tritosylate shown in structural formula (II) is obtained by carrying out a reaction between a compound shown in structural formula (I) and toluene sulfonyl chloride in an anhydrous pyridine solvent according to an equal molar ratio. According to the method, use of an inorganic alkali catalyst Na2CO3 or K2CO3 is avoided, problems about hydrolysis of the toluene sulfonyl chloride are solved, and an obtained product is high in yield and free of other side reaction, and is not required to be separated by virtue of a method of column chromatography and the like.
- -
-
Paragraph 0010
(2017/08/29)
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- Ionic liquid brush as an efficient and reusable heterogeneous catalytic assembly for the tosylation of phenols and alcohols in neat water
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A very efficient and reusable heterogeneous ionic liquid brush assembly was developed. The catalyst exhibits high catalytic activity for the tosylation of phenols and alcohols in neat water. Moreover, the catalyst shows outstanding stability and reusability, and it can be simply and effectively recovered and reused five times without noticeable loss of catalytic activity.
- Feng, Simin,Li, Jing,Wei, Junfa
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supporting information
p. 4743 - 4746
(2017/07/12)
-
- The influence of electronic perturbations on the Sulfur-Fluorine Gauche Effect Dedicated to Prof. Dr. Antonio Togni on the occasion of his 60th birthday.
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Herein, a solution phase NMR conformer population analysis is employed to probe the effect of remote electronic perturbations on the conformational equilibria of a series of para-substituted β-fluorosulfides (1), sulfoxides (2) and sulfone derivatives (3). Conformations that allow for stabilizing stereoelectronic (σC-H → σ?C-F) and electrostatic (Fδ-...Sδ+) interactions predominate: this is consistent with the Sulfur-Fluorine Gauche Effect. The molar fractions (χ) of the two possible gauche conformers correlate linearly with the electron-withdrawing aptitude of the para-substituent, rendering the system ideally suited for a Hammett-type analysis. Despite the clear influence that the remote para-substituents have on conformer population, this is superseded by the oxidation state on sulfur (II, IV, VI), where an increased preference for the gauche conformer follows the trend: sulfide sulfone sulfoxide. It is envisaged that this proof of concept in controlling conformer population, either by proximal (oxidation state) or remote tuning (para-substituent), will find application in molecular design.
- Thiehoff, Christian,Schifferer, Lukas,Daniliuc, Constantin G.,Santschi, Nico,Gilmour, Ryan
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supporting information
p. 121 - 126
(2016/01/25)
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- Isotope Effects in the Solvolysis of Sterically Hindered Arenesulfonyl Chlorides
-
Solvent isotope effects in the ethanolysis of sterically hindered arenesulfonyl chlorides ruled out a proton transfer in the rate-determining step and agreed with a SN2 mechanism involving at least a second solvent molecule in the transition state (TS). The lack of a secondary kinetic isotope effect in the o-alkyl groups allows us to disregard the possible contribution of σ-π hyperconjugation. The measured activation parameters are consistent with a SN2 mechanism involving the participation of solvent molecules in the TS, possibly forming a cyclic TS through a chain of solvent molecules.
- Iazykov, Mykyta,Canle L., Moisés,Santaballa, J. Arturo,Rublova, Ludmila
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p. 744 - 750
(2015/10/06)
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- An efficient method for the preparation of sulfonyl chlorides: Reaction of disulfides or thiols with sodium hypochlorite pentahydrate (NaOCl·5H2O) crystals
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The reaction of disulfides or thiols with sodium hypochlorite pentahydrate in acetic acid efficiently provided the corresponding sulfonyl chlorides in high yields.
- Okada, Tomohide,Matsumuro, Hiroaki,Iwai, Toshiaki,Kitagawa, Saori,Yamazaki, Kento,Akiyama, Tomomi,Asawa, Tomotake,Sugiyama, Yukihiro,Kimura, Yoshikazu,Kirihara, Masayuki
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p. 185 - 187
(2015/02/19)
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- Design, synthesis, and biological evaluation of deuterated C-aryl glycoside as a potent and long-acting renal sodium-dependent glucose cotransporter 2 inhibitor for the treatment of type 2 diabetes
-
SGLT2 inhibitors deuterated at sites susceptible to oxidative metabolism were found to have a slightly longer tmax and half-life (t 1/2), dose-dependent increase in urinary glucose excretion (UGE) in rats, and slightly superior effects on UGE in dogs while retaining similar in vitro inhibitory activities against hSGLT2. In particular, deuterated compound 41 has the potential to be a robust long-acting antidiabetic agent.
- Xu, Ge,Lv, Binhua,Roberge, Jacques Y.,Xu, Baihua,Du, Jiyan,Dong, Jiajia,Chen, Yuanwei,Peng, Kun,Zhang, Lili,Tang, Xinxing,Feng, Yan,Xu, Min,Fu, Wei,Zhang, Wenbin,Zhu, Liangcheng,Deng, Zhongping,Sheng, Zelin,Welihinda, Ajith,Sun, Xun
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p. 1236 - 1251
(2014/03/21)
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- A dicationic, podand-like, ionic liquid water system accelerated copper-catalyzed azide-alkyne click reaction
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In this work, an effective, task specific, dicationic, podand-like ionic liquid was synthesized and applied to improve the capability features of click reaction. Moreover, to broaden the scope and decreasing the serious limitations of preparation methods of organic azides, a simple green procedure for the preparation of alkyl azides, the fundamental starting materials in click reactions, from alcohols under solvent-free conditions and microwave irradiation has been reported, for the first time.
- Javaherian, Mohammad,Kazemi, Foad,Ghaemi, Masoumeh
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p. 1643 - 1647
(2015/01/09)
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- A kinetic study on nucleophilic displacement reactions of aryl benzenesulfonates with potassium ethoxide: Role of K+ ion and reaction mechanism deduced from analyses of LFERs and activation parameters
-
Pseudofirst-order rate constants (kobsd) have been measured spectrophotometrically for the nucleophilic substitution reactions of 2,4-dinitrophenyl X-substituted benzenesulfonates 4a-f and Y-substituted phenyl benzenesulfonates 5a-k with EtOK in anhydrous ethanol. Dissection of k obsd into kEtO- and kEtOK (i.e., the second-order rate constants for the reactions with the dissociated EtO - and ion-paired EtOK, respectively) shows that the ion-paired EtOK is more reactive than the dissociated EtO-, indicating that K + ion catalyzes the reaction. The catalytic effect exerted by K + ion (e.g., the kEtOK/kEtO- ratio) decreases linearly as the substituent X in the benzenesulfonyl moiety changes from an electron-donating group (EDG) to an electron-withdrawing group (EWG), but it is independent of the electronic nature of the substituent Y in the leaving group. The reactions have been concluded to proceed through a concerted mechanism from analyses of the kinetic data through linear free energy relationships (e.g., the Bronsted-type, Hammett, and Yukawa-Tsuno plots). K+ ion catalyzes the reactions by increasing the electrophilicity of the reaction center through a cyclic transition state (TS) rather than by increasing the nucleofugality of the leaving group. Activation parameters (e.g., ΔH? and ΔS?) determined from the reactions performed at five different temperatures further support the proposed mechanism and TS structures.
- Um, Ik-Hwan,Kang, Ji-Sun,Shin, Young-Hee,Buncel, Erwin
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p. 490 - 497
(2013/03/13)
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- Silver(I)-mediated reaction of trimethylsilylated arylacetylenes with sulfonyl chlorides: Unexpected formation of vinyl sulfones
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A novel reaction of trimethylsilylated arylacetylenes with sulfonyl chlorides was performed in the presence of silver nitrate or triflate. Conjugated vinyl sulfones as dramatic products were obtained in moderate yields and with Z-selectivity. A free radical mechanism has been proposed to account for the formation of the products.
- Deng, Gui Sheng,Sun, Teng Fei
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p. 1115 - 1118,4
(2020/08/20)
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- TiCl4-mediated direct N-alkylation of sulfonamides with inactive ethers
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A TiCl4-mediated intermolecular or intramolecular direct N-alkylation reaction of sulfonamides with inactive ethers as alkylating agents was successfully achieved. This method provides a novel approach towards N-alkyl sulfonamides from inactive ethers via an easy workup procedure. Georg Thieme Verlag Stuttgart · New York.
- Chen, Jiayan,Dang, Ling,Li, Qiang,Ye, Yong,Fu, Shaomin,Zeng, Wei
-
supporting information; experimental part
p. 595 - 600
(2012/03/27)
-
- Itraconazole Side Chain Analogues: Structure-Activity Relationship Studies for Inhibition of Endothelial Cell Proliferation, Vascular Endothelial Growth Factor Receptor 2 (VEGFR2) Glycosylation, and Hedgehog Signaling
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Itraconazole is an antifungal drug that was recently found to possess potent antiangiogenic activity and anti-hedgehog (Hh) pathway activity. To search for analogues of itraconazole with greater potency and to understand the structure-activity relationship in both antiangiogenic and Hh targeting activity, 25 itraconazole side chain analogues were synthesized and assayed for inhibition of endothelial cell proliferation and Gli1 transcription in a medulloblastoma (MB) culture. Through this analysis, we have identified analogues with increased potency for inhibiting endothelial cell proliferation and the Hh pathway, as well as VEGFR2 glycosylation that was recently found to be inhibited by itraconazole. An SAR analysis of these activities revealed that potent activity of the analogues against VEGFR2 glycosylation was generally driven by side chains of at least four carbons in composition with branching at the α or β position. SAR trends for targeting the Hh pathway were divergent from those related to HUVEC proliferation or VEGFR2 glycosylation. These results also suggest that modification of the sec-butyl side chain can lead to enhancement of the biological activity of itraconazole.
- Shi, Wei,Nacev, Benjamin A.,Aftab, Blake T.,Head, Sarah,Rudin, Charles M.,Liu, Jun O.
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supporting information; experimental part
p. 7363 - 7374
(2011/12/04)
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- Catalysis of the ethanolysis of N-methyl-N-nitroso-p-toluenesulfonamide by alkali metal ions
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The goal of this study was to report on the catalytic effects by alkali-metal ions in the ethanolysis of N-methyl-N-nitroso-p-toluenesulfonamide (MNTS). We confirmed that the nucleophilic attack at the sulfur center was the only reaction pathway. The reactions of MNTS with metal ethoxides (MOEt) were discussed on basis of a kinetic scheme considering simultaneous reaction of free ethoxide and ion-paired ethoxide with the substrate. The trend for ion-paired ethoxide reactivity was clear and showed an increase on increasing the size of the ion (Cs+>K+>Na+>Li+). For evaluate the free ethoxide reactivity we performed additional experiments in the presence of the complexing agents 18-crown-6 ether (18-C-6) and 2,5,8,11,14-pentaoxapentadecane (glyme). The results obtained were discussed in terms of the interaction of the metal ions with the ground state and the transition state. ARKAT-USA, Inc.
- Garcia-Rio, Luis,Raposo-Barreiro, Maria Luz,Rodriguez-Dafonte, Pedro
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scheme or table
p. 272 - 282
(2011/06/25)
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- Design, synthesis, and structure-affinity relationships of regioisomeric N-benzyl alkyl ether piperazine derivatives as σ-1 receptor ligands
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A series of N-(benzofuran-2-ylmethyl)-N′-benzylpiperazines bearing alkyl or fluoroalkyl aryl ethers were synthesized and evaluated at various central nervous system receptors. Examination of in vitro σ1 {[3H](+)-pentazocine} and σ2 ([3H]DTG) receptor binding profiles of piperazines 11-13 and 25-36 revealed several highly potent and σ1 selective ligands, notably, N-(benzofuran-2- ylmethyl)-N′-(4′-methoxybenzyl)piperazine (13, Ki = 2.7 nM, σ2/σ1 = 38) and N-(benzofuran-2-ylmethyl)- N′-(4′-(2″-fluoroethoxy)benzyl)piperazine (30, Ki = 2.6 nM, σ2/σ1 = 187). Structural features for optimal σ1 receptor affinity and selectivity over the σ2 receptor were identified. On the basis of its favorable log D value, 13 was selected as a candidate for the development of a σ1 receptor positron emission tomography radiotracer. [ 11C]13 showed high uptake in the brain and other σ receptor-rich organs of a Papio hamadryas baboon. The in vivo evaluation of [11C]13 indicates that this radiotracer is a suitable candidate for imaging the σ1 receptor in neurodegenerative processes.
- Moussa, Iman A.,Banister, Samuel D.,Beinat, Corinne,Giboureau, Nicolas,Reynolds, Aaron J.,Kassiou, Michael
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experimental part
p. 6228 - 6239
(2010/11/02)
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- Amphiphilic organocatalyst for schotten-baumann-type tosylation of alcohols under organic solvent free condition
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A Tosylation of primary alcohol with tosyl chloride was performed effectively with an W-hexadecylimidazole catalyst in water containing K 2CO3 aggregation of the catalyst carrying a hydrophobic methylene chain worked as a substitute for organic solvent.
- Asano, Keisuke,Matsubara, Seijiro
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supporting information; experimental part
p. 1757 - 1759
(2009/09/06)
-
- Chemoselective and scalable preparation of alkyl tosylates under solvent-free conditions
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The improved method for the efficient tosylation of alcohols has been reported using two procedures (A and B). Procedure A: methanol, ethanol, benzyl alcohols, and valuable ethylene glycols can be converted into their corresponding alkyl tosylates in very fast, simple, and efficient grinding method using potassium carbonate as solid base. Other primary and secondary alcohols need to add potassium hydroxide to reaction mixture (procedure B). High selectivity of tosylation was observed for these two procedures. Scale up ability was found in this method even in 100 mmol of substrate. The present method is the example of solid-state tosylation using tosyl chloride, and is a green chemical process due to solvent-free conditions.
- Kazemi, Foad,Massah, Ahmad R.,Javaherian, Mohammad
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p. 5083 - 5087
(2008/02/01)
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- An efficient one-pot conversion of THP and TMS ethers to sulfonate esters using FeCl3-montmorillonite K-10 clay
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Various tetrahydropyranyl and trimethylsilyl ethers are efficiently transformed into the corresponding sulfonate esters with sulfonyl chlorides in the presence of FeCl3-Montmorillonite K-10 clay.
- Movassagh, Barahman,Shokri, Salman
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p. 763 - 765
(2007/10/03)
-
- Alkylated alkyl polyglucoside non-ionic surfactants
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A petro-chemical free nonionic surfactant is prepared by the alkylation of an alkyl polyglucoside (APG). Under suitable alkylation reaction conditions, the surfactants are preferably prepared by the reaction of an APG with either alkyl halide or an alkyl tosylate. These surfactants are low foaming and exhibit excellent detergency.
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- Smiles-type free radical rearrangement of aromatic sulfonates and sulfonamides: Syntheses of arylethanols and arylethylamines
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Smiles-type free radical rearrangements of arenesulfonates and arenesulfonamides are exploited for synthetic purposes. 4-Substituted benzenesulfonates cause Smiles-type rearrangement only when substituted by an electron withdrawing group. Therefore, ipso-sttack by an alkyl radical on arenesulfonates takes place in an electrophilic manner. Arenesulfonamides rearrange only when the amide nitrogen is substituted by an alkoxycarbonyl group, due to the electron withdrawing nature of this group. Sulfonates and the N-ethoxycarbonylsulfonamide derivatives of naphthalene, quinoline, and thiophene cause more rearrangement and show synthetic utility. Aromatic amino acid analogues were synthesized by Smiles-type rearrangement with moderate yields. The radical Smiles-type rearrangement of sulfonate and sulfonamide derivatives can be a useful synthetic route when we understand the electronic character of these reactions.
- Tada, Masaru,Shijima, Hiroyasu,Nakamura, Masaharu
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p. 2499 - 2505
(2007/10/03)
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- MANUFACTURING METHOD FOR POLYCARBONATE
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A method for manufacturing polycarbonate by melt-polycondensing bisphenol and carbonic acid diester uses as catalyst an alkali metal compound and/or alkaline earth metal compound (a). The catalyst is added to the bisphenol prior to the melt polycondensation, in an effective amount, i.e., the amount of alkali metal compound and/or alkaline earth metal compound (a) that acts effectively as a catalyst, is contained in said bisphenol, and is controlled to have the same catalytic activity as 1×10?8 to 1×10?6 mole of bisphenol disodium salt per mole of pure bisphenol A. The method conducts the reaction efficiently from the initial stage in a stable manner to obtain polycarbonate with good color, good heat stability and color stability during molding and the like.
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- Montmorillonite clay catalyzed tosylation of alcohols and selective monotosylation of diols with p-toluenesulfonic acid: An enviro-economic route
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An enviro-economic route for tosylation of alcohols and selective monotosylation of diols in good yield directly using p-toluenesulfonic acid together with metal-exchanged montmorillonite instead of p-toluenesulfonyl chloride or p-toluenesulfonic anhydrid
- Choudary, Boyapati M.,Chowdari, Naidu S.,Kantam, Mannepalli L.
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p. 7291 - 7298
(2007/10/03)
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- Effect of the leaving group on the alkylation diastereoselectivity of the Schollkopf chiral auxiliary
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Tosylates, diphenylphosphates and bromides were employed to study the effect of the leaving group on the alkylation diastereoselectivity of the Schollkopf chiral auxiliary 1 at aliphatic, benzylic, propargylic and allylic electrophilic centers. The diastereoselectivity generally follows the pattern: diphenylphosphate > tosylate > bromide. In terms of both diastereoselectivity and yield, each leaving group possesses a different advantage.
- Ma, Chunrong,He, Xiaohui,Liu, Xiaoxiang,Yu, Shu,Zhao, Shuo,Cook, James M.
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p. 2917 - 2918
(2007/10/03)
-
- Process for preparation of oxyglutaric acid ester derivatives
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A process for preparing an oxyglutaric acid ester derivative of the formula: STR1 in which each of R1 and R2 is C1-5 alkoxy, C1-7 aralkyloxy, C7-9 halogenated aralkyloxy or phenyl, R4 is a hydroxyl-protecting group, and R5 is C1-10 alkyl which may have a substituent, comprises the steps of reacting a methyl phosphonate derivative or methyl phosphine oxide derivative with an oxyglutaric acid mono-ester to give a reaction product which comprises an oxyglutaric acid derivative having a phosphorus-containing group and a pentenedioic acid mono-ester (by-product), removing the pendenedioic acid mono-ester from the reaction product to isolate the oxyglutaric acid derivative, and converting the isolated oxyglutaric acid derivative into the oxyglutaric acid ester derivative. A process for obtaining an optically active oxyglutaric acid ester derivative is also disclosed.
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-
- Scavenger assisted combinatorial process for preparing libraries of tertiary amine compounds
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This invention relates to a novel solution phase process for the preparation of tertiary amine combinatorial libraries. These libraries have utility for drug discovery and are used to form wellplate components of novel assay kits.
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-
- Clean catalysis with ionic solvents - Phosphonium tosylates for hydroformylation
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High-melting phosphonium tosylates are synthesised and applied for the first time as solvents in catalytic hydroformylation reactions; variation in the substituents attached to phosphorus can lead to markedly different results; the catalyst systems are non-corrosive, easily manipulated and can readily be recovered and reused.
- Karodia, Nazira,Guise, Steven,Newlands, Craig,Andersen, Jo-Ann
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p. 2341 - 2342
(2007/10/03)
-
- Autoassembly of cage structures 9. Complete autoassembly of dilactones of α,α'-dihydroxy-α,α'-dialkoxycarbonyladipic and -pimelic acids
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Complete autoassembly of dilactones 4-6 from dihydroxytetraesters of the type X2YC(CH2)nCYX2 (X = CO2R, Y=OH, n = 2,3) was performed in high yields under the conditions of acid or base catalysis.The classic syntheses of the Troeger's base, Meerwein ester, and dilactams were considered from the viewpoint of bicycle autoassembly. - Key words: α,ω-alkylene-bis-tartronates; autoassembly of dilactones of α,α'-dihydroxy-α,α'-dialkoxycarbonyladipic and -pimelic acids; acidic and base catalysis; NMR, IR, and mass spectra.
- Kostyanovsky, R. G.,El'natanov, Yu. I.,Krutius, O. N.,Voznesensky, V. N.
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p. 318 - 321
(2007/10/02)
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- Facile esterification of sulfonic acids and carboxylic acids with triethylorthoacetate
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Triethylorthoacetate was found to be surprisingly more effective than triethylorthoformate in the esterification of sulfonic acids and carboxylic acids. Using this reagent, esters of sulfonic and carboxylic acids are prepared in high yields.
- Trujillo, John I.,Gopalan, Aravamudan S.
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p. 7355 - 7358
(2007/10/02)
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- Limitations of the Transition-state Variation Model. Part 3. Solvolyses of Electron-rich Benzenesulphonyl Chlorides
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Rate constants for solvolyses of 4-methoxy-2,6-dimethylbenzenesulphonyl chloride 3 (Z = OMe) and of 4-methyl- and 4-methoxybenzenesulphonyl chlorides 4 (Z = Me and OMe) are reported for aqueous binary mixtures with acetone, ethanol and methanol.Some additional rate constants are reported for aqueous acetonitrile and dioxane mixtures, as well as product selectivities (S) in alcohol-water mixtures.For each binary mixture, rates of solvolyses of 3 (Z = OMe) vs.YCl or Y are approximately bilinear.As water is added to alcohol, S values for solvolyses of 3 (Z = OMe) pass through a maximum and for solvolyses of 4-methoxybenzenesulphonyl chloride 4 (Z = OMe) the position of the maximum shifts to more aqueous media.For solvolyses of 4-methyl-benzenesulphonyl chloride 4 (Z = Me), S values are shifted such that they reach a plateau rather than a maximum, and the rate-rate profiles with YCl are approximately linear rather than bilinear.All of rate-rate profiles show 'dispersion' into separate correlations for the various binary mixtures.These substituent effects follow the same trends as corresponding solvolyses of benzoyl chloride and strengthen recent proposals that solvolyses of 3 (Z = Me) proceed via competing (dual) reaction channels.
- Koo, In Sun,Bentley, William T.,Llewellyn, Gareth,Yang, Kiyull
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p. 1175 - 1179
(2007/10/02)
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- Alkynyliodonium Salts as Alkynylating Reagents: Direct Conversion of Alkynylphenyliodonium Tosylates to Dialkyl Alkynylphosphonates with Trialkyl Phosphites
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The treatment of various alkynyl(phenyl)iodonium tosylates 1 (R = t-Bu, s-Bu, i-Pr, cyclopentyl, Ph, and p-MeC6H4; X(-) = OTs(-)) with neat trimethyl phosphite gave the dimethyl alkynylphosphonates 4a and 4d-h in isolated yields ranging from 34 to 90percent.Similar treatment of 1 (R = t-Bu, X(-) = OTs(-)) with neat triethyl and triisopropyl phosphites gave the diethyl and diisopropyl alkynylphosphonates 4b (81percent) and 4c (58percent).The byproducts of these reactions are alkyl tosylates and iodobenzene.The high yields of iodobenzene, determined by GC analysis for the reactions of 1 (R = s-Bu, p-tolyl; X(-) = OTs(-)) with trimethyl phosphite, indicate that the cleavage of the alkynyl(phenyl)iodonium ions with trialkyl phosphites proceeds with high regioselectivity at the alkynyl ligand.
- Lodaya, Jayant S.,Koser, Gerald F.
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p. 1513 - 1516
(2007/10/02)
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- Sulphonic Acid-induced Fragmentation of Dialkyl Acylphosphonates, Formation of Alkyl Carboxylates and Alkyl Sulphonates
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Heating of dialkyl acylphosphonates with sulphonic acids under anhydrous conditions leads to the formation of alkyl sulphonates and alkyl carboxylates. 31P N.m.r. spectroscopy revealed that the reaction of equimolar amounts of dimethyl benzoylphosphonate (1) and toluene-p-sulphonic acid at room temperature gives dimethyl phosphonate (6) in 50percent yield.It is proposed that the by-product of this reaction, benzoic toluene-p-sulphonic anhydride (8), reacts with the excess of toluene-p-sulphonic acid, to yield toluene-p-sulphonic anhydride (9) and benzoic acid.Heating of these two compounds with dimethyl phosphonate was shown to yield methyl toluene-p-sulphonate and methyl benzoate, respectively.A postulated by-product of these reactions is phosphenous acid (HPO2).Quantum mechanical calculations by the MNDO/H method carried out on dimethyl benzoylphosphonate and its protonation products show that the preferred site of protonation of dimethyl benzoylphosphonate is the P=O oxygen, and that protonation at this site is followed by C-P bond breaking, with zero energy of activation, leading to dimethyl phosphite and benzoylium cation.
- Breuer, Eli,Karaman, Rafik,Goldblum, Amiram,Leader, Haim
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p. 2029 - 2034
(2007/10/02)
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- Selective Sulfonylating Agents
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A variety of bulky sulfonyl chlorides have been investigated as sulfonylating reagents for polyol systems in an endeavour to find a selective reagent that would also give rise to a reactive sulfonate ester group.
- Guthrie, R. D. (Gus),Thang, San
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p. 2133 - 2136
(2007/10/02)
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- Bromonitromethane. A Versatile Electrophile
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Pathways in reactions of bromonitromethane with a variety of nucleophiles have been investigated.With thiolates, the electrophilic centre is bromine and the initial products are disulphides.When the thiolate ion itself carries an electrophilic centre such as carbonyl or cyano β-to sulphur, the product is a nitrothiophene derived from subsequent reaction of the first-formed disulphide with nitronate ion displaced in the initial process.This provides a generalisation of earlier nitrothiophene synthesis by this route.In reactions with arenesulphinate ion, the electrophilic centre is also bromine and equilibration between the initial reactants and the initial products, sulphonyl bromide and nitronate ion, is established.The components of the equilibrium subsequently react either with each other or with the solvent.Reactions with sulphides are slow and distal substituents such as hydroxy- or cyano- so much reduce reactivity that no reaction is observed.Dimethyl sulfide attacks bromonitromethane at the carbon atom,and subsequent attack on the nitromethyl sulphonium salt initially formed gives methylthionitromethane and trimethylsulphonium bromide.Iodide ion attacks at bromine to give iodine, presumably via iodine bromide, but with tervalent phosphorus nucleophiles, attack is at oxygen giving the corresponding oxides and HCN in a double deoxygenation sequence.For hydroxide, methoxide and hydride ions (from sodium borohydride), nucleophilic attack is at hydrogen and the nitronate ion produced is inert to further attack.There is no evidence of carbene formation by α-elimination.When the anion of bromonitromethane is allowed to react with tributylboron, the anionic migration-displacement which follows boron-carbon bond formation, yields 1-nitropentane.The anion of bromonitromethane is unreactive towards aldehydes and electrophilic alkenes.
- Fishwick, Brian R.,Rowles, David K.,Stirling, Charles J. M.
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p. 1171 - 1180
(2007/10/02)
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- Rearrangements of 2-Phenylthioethanols with Alkenyl, Alkynyl, Ester, and Other Functionalised Alkyl Substituents at the Migration Origin: Synthesis of γ-Phenylthiocrotonate Esters
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The effects of functional groups near the migration origin in and PhS shifts are explored: an α-CO2R group prevents migration, α or β vinyl groups have only steric effects, alkynyl or CO2Et groups encourage rearrangement and provide routes to γ-phenylthio unsaturated esters and ketones.
- Brownbridge, Peter,Hunt, Paul G.,Warren, Stuart
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p. 1695 - 1706
(2007/10/02)
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- Importance of repulsion of lone electron pairs in the enhanced reactivity of 1,8-naphthyridine and the large α-effect of hydrazine in the aminolyses of p-toluenesulfonyl chloride
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The rates of aminolyses of p-toluenesulfonyl chloride with primary and tertiary amines have been determined both in acetonitrile and in ethanol.The Broensted plots of log krel again pKa' values fo amines (except hydrazine and 1,8-naphthyridine in acetonitrile) gave a good correlation when the aminolyses were carried out in acetonitrile.In ethanol, however, although Broensted plots with all tertiary amines show a good correlation, less basic hydrazine shows a higher reactivity than n-butylamine.The abnormal rate enhancement found with hydrazine is undoubtedly due to the α-effect, while with 1,8-naphthyridine in acetonitrile is considered to be due to the repulsion of two lone electron pairs on the two nitrogen atoms in 1,8-naphthyridine.
- Oae, Shigeru,Kadoma, Yoshihito
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p. 1184 - 1188
(2007/10/02)
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- REACTION OF PHOSPHORUS OXYACID ESTERS WITH p-TOLUENESULFONIC ACID
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The reaction of primary alkyl esters of phosphorus oxyacids with p-toluenesulfonic acid (TsOH) in refluxing solvents gave the corresponding p-toluenesulfonates (TsOR).We found that the secondary alkyl esters reacted with TsOH at lower temperature (r.t.-40 deg C) to afford TsORs in good yields.It is suggested that sulfonic acids may be useful for the selective dealkylation of mixed esters.Keywords-p-toluenesulfonic acid; p-toluenesulfonate; trialkyl phosphate; trialkyl phosphite; dialkyl phenylphosphonate; transesterification; dealkylation; solvolysis.
- Nitta, Yoshihiro,Arakawa, Yasushi,Ueyama, Naoto
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p. 2710 - 2718
(2007/10/02)
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- Reaction of Carboxylic Acid Esters with p-Toluenesulfonic Acid
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The reaction of carboxylic acid esters with an excess of p-toluenesulfonic acid gave the corresponding p-toluenesulfonates.The mechanism of the transesterification is discussed.
- Nitta, Yoshihiro,Arakawa, Yasushi
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p. 1380 - 1386
(2007/10/02)
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- The reactions of some α-halo-β-ketosulfones with hard and soft nucleophiles. A preparation of sulfinate esters
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The α-halo-β-ketosulfonyl functionality was attacked by ethanethiolate at the halogen which, in the presence of a proton source, usually resulted in reduction to the β-ketosulfone.A range of other soft nucleophiles did not react, whereas hard nucleophiles invariably attacked at the carbonyl, with subsequent cleavage to α-halosulfones.Ambident arylsulfinate anions usually attacked at halogen to form the sulfonyl halide, which reacted with excess sulfinate to give an intermediate that is readily attacked by alcohols.This reaction resulted in the formation of alkyl arylsulfinate esters in reasonable yields.The same reaction occurred when sulfonyl chlorides were reacted with sulfinate salts and it was rationalized by using HSAB principles.Spectral properties of some sulfinate esters are presented.
- Grossert, J. Stuart,Dubey, Pramod K.,Elwood, Tom
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p. 1263 - 1267
(2007/10/02)
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- A NEW METHOD FOR THE ESTERIFICATION OF SULPHONIC ACIDS
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Sulphonic acids can be smoothly converted to their methyl and ethyl esters by reaction with trimethyl and triethyl orthoformate, respectively
- Padmapriya, A. A.,Just, G.,Lewis, N. G.
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p. 1057 - 1062
(2007/10/02)
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- NMR DETERMINATION OF ABSOLUTE SITE-SPECIFIC NATURAL ISOTOPE RATIOS OF HYDROGEN IN ORGANIC MOLECULES. ANALYTICAL AND MECHANISTIC APPLICATIONS
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It has been shown that the "internal" isotope distribution within a given molecular species at the natural abundance level is accessible by a new method, SNIF-nmr, which is based on deuterium NMR.Relative internal factors, Ri/j, have been defined which enable the isotope content of a given site, i, to be compared to that of another molecular site, j, taken as a reference.Several referencing methods intended to provide direct access to relative externals, Ti, and absolute, (D/H), site-specific parameters, are now discussed from both the theoretical and the experimental points of wiev.In the intramolecular referencing method, which involves a time-consuming chemical transformation of the sample, the risk exists of more or less systematic errors resulting from discriminating fractionation effects.However this technique offers, conversely, an interesting way of investigating kinetic isotope effects without the need for specific labelling.In spite of its lower spectral precision the external referencing method has the advantage of being fast and less sensitive to systemetic errors and may be used for direct rough routine determinations of the site-specific isotope contents.More precise results can be obtained, at the price of contaminating the sample, when an intermolecular reference is added and signal heights are used, remembering however that the intensity parameters then have no strict physical meaning in terms of absolute isotope contents.The site-specific parameters, Ti and (D/H)i thus accessible, provide new information on the mechanisms of the fractionation effects occuring in natural conditions and exaples are considered.
- Martin, G. J.,Sun, X. Y.,Guillou, C.,Martin, M. L.
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p. 3285 - 3296
(2007/10/02)
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- Bromonitromethane, a Versatile Electrophile: Reactions with Feebly Basic Nucleophiles
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Bromonitromethane reacts with feebly basic sulphur, phosphorus, and halogen nucleophiles at bromine or at carbon; the anion of bromonitromethane reacts with tributylboron to give 1-nitropentane.
- Fishwick, Brian R.,Rowles, David K.,Stirling, Charles J. M.
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p. 835 - 836
(2007/10/02)
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- Reaction of Ethyl Acetoacetate with p-Toluenesulfonic Acid: Formation of Ethyl Isodehydroacetate and/or Ethyl p-Toluenesolfonate
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Treatment of ethyl acetoacetate with anhydrous p-toluenesulfonic acid at room temperature led to ethyl isodehydroacetate (1) in high yield by acid-catalysed condensation.On the other hand, in refluxing toluene, the unexpected ethyl ester of p-toluenesulfonic acid (2) was formed in moderate yield.This constitutes a new direct esterification of arenesulfonic acids. Keywords---ethyl acetoacetate; p-toluenesulfonic acid; ethyl isodehydroacetate; ethyl p-toluenesulfonate; condensation; direct esterification
- Nitta, Yoshihiro,Arakawa, Yasushi
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p. 1385 - 1388
(2007/10/02)
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- 2,2-Bis(ethylthio)ethanenitrile: preparation and use as a one or two carbon nucleophile
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2,2-Bis(ethylthio)ethanenitrile 1 was prepared in high yield from 2,2-bis(ethylthio)ethanal 2.Alkylation of the potassium salt of 1 with various alkylating agents and conjugate addition to cyclic α,β-unsaturated ketones provided high yields of the alkylation products of 1.The potential one and two carbon chain extension capability of this new reagent has been demonstrated.
- Bates, Gordon S.,Ramaswamy, S.
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p. 2006 - 2009
(2007/10/02)
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- Enamines of 2,2-bis(ethylthio)ethanal: a convenient route to γ-keto crotonate derivatives
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A new α-oxoaldehyde reagent, 2,2-bis(ethylthio)ethanal 1, has been prepared in high yield from ethanedial.Alkylation of the potassium salt of the enamines of 1 with various alkylating agents followed by in situ hydrolysis of the intermediate imine afforded high yields of the alkylation products of 1.This new reagent was used in the synthesis of a chiral potential precursor of the macrocyclic fragment of cytochalasins A,B, and F, as well as in the syntheses of the physiologically active diolides pyrenophorin and norpyrenophorin.
- Bates, Gordon S.,Ramaswamy, S.
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p. 2466 - 2475
(2007/10/02)
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