- Metal-Free Fast Azidation by Using Tetrabutylammonium Azide: Effective Synthesis of Alkyl Azides and Well-Defined Azido-End Polymethacrylates
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An effective method to synthesize azido-end polymethacrylates from tetrabutylammonium azide (BNN3) in a nonpolar solvent (toluene) was developed. Several low-mass alkyl halides were reacted with BNN3 in toluene as model reactions and
- Wang, Chen-Gang,Chong, Amerlyn Ming Liing,Lu, Yunpeng,Liu, Xu,Goto, Atsushi
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- ATRP, subsequent azide substitution and 'click' chemistry: Three reactions using one catalyst in one pot
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This communication describes a novel and fast reaction to substitute the living chain end after Atom Transfer Radical Polymerization (ATRP) by an azide functionality. The reaction is catalyzed by the ATRP catalyst at room temperature in aqueous solution a
- De Graaf, Albert J.,Mastrobattista, Enrico,Van Nostrum, Cornelus F.,Rijkers, Dirk T. S.,Hennink, Wim E.,Vermonden, Tina
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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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- Two-Step Protocol for Iodotrimethylsilane-Mediated Deoxy-Functionalization of Alcohols
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We have developed a two-step protocol for iodotrimethylsilane-mediated deoxy-functionalization of primary and secondary alcohols to afford products containing a C?N, C?S, or C?O bond. In the first step the alcohol undergoes iodination with iodotrimethylsilane, and in the second, the iodine atom is replaced by a N, S, or O nucleophile. Compared with traditional Mitsunobu reaction, non-acidic pre-nucleophiles can be used, and the reaction proceeds with retention of configuration. This operationally simple, highly efficient protocol can be used for some natural products and small-molecule drugs containing hydroxy-group.
- Chen, Yuming,He, Ru,Song, Hongjian,Yu, Guoqing,Li, Chenglin,Liu, Yuxiu,Wang, Qingmin
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supporting information
p. 1179 - 1183
(2021/02/01)
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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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- Furfuryl Cation Induced Three-Component Reaction to Synthesize Triazole-Substituted Thioesters
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A furfuryl cation induced three-component thioesterification reaction between thiols, 5-bromo-2-furylcarbinols and azides is reported. This metal-free method relies on the acetyl chloride/HFIP-mediated cascade formal [3+2] cycloaddition/ring-opening/thioesterification, which allows the efficient construction of a series of complex triazole-thioesters linked with an (Z)-olefin. Selenols are also suitable for this strategy. Further derivatization of thioesters highlighted the potential utility of our method.
- Zhong, Ying,Xu, Xiaoming,Xing, Qingzhao,Yang, Song,Gou, Jing,Gao, Ziwei,Yu, Binxun
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supporting information
p. 3251 - 3256
(2020/05/25)
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- Highly regioselective and sustainable solar click reaction: A new post-synthetic modified triazole organic polymer as a recyclable photocatalyst for regioselective azide-alkyne cycloaddition reaction
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The synthesis of pharmaceutically active 1,2,3-triazoles has been continuously scrutinized in the search for unique and effective catalysts to make the process efficient, green, and sustainable. Here, we are presenting a new visible light active Ni(ii) cyclam-integrated triazole-linked organic polymer (Ni-TLOP) photocatalyst for the synthesis of 1,2,3-triazole compounds with excellent efficiency and regioselectivity. The reaction was studied for a series of substrates and the absolute regioselectivity of a representative triazole product has also been confirmed by X-ray crystallography. The proficiency and chemical orthogonality of the Ni-TLOP are remarkable and it shows enhanced efficiency and regioselectivity. The use of a recyclable photocatalyst and non-hazardous reagents makes the catalytic system sustainable and environmentally friendly. This photocatalyzed click reaction technique has been successfully applied to the expedient synthesis of one of the most sold anti-epileptic drugs rufinamide.
- Yadav, Dolly,Singh, Nem,Kim, Tae Wu,Kim, Jae Young,Park, No-Joong,Baeg, Jin-Ook
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supporting information
p. 2677 - 2685
(2019/06/13)
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- Reactions of α-haloacroleins with azides: Highly regioselective synthesis of formyl triazoles
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A general metal-free route to 1,4-disubstituted and 1,4,5-trisubstituted 1,2,3-triazoles was developed. α-Haloacroleins reacted with organic azides in a DMSO/H2O mixture solvent at room temperature to produce 1,4-disubstituted triazoles (up to 99%) with exclusive regioselectivities. This protocol is convenient and scalable with a broad substrate scope including aliphatic and aromatic azides. The resulting triazoles exhibited an aldehyde group at the C4 position and demonstrated synthetic utilizations. One 1,2,3-triazole compound containing diastereotopic protons was also identified.
- Zhang, Dongsheng,Fan, Yingzhu,Yan, Zhongliang,Nie, Yi,Xiong, Xingquan,Gao, Lizhu
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supporting information
p. 4211 - 4216
(2019/08/07)
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- Thermal azide-Alkene cycloaddition reactions: straightforward multi-gram access to Δ2-1,2,3-Triazolines in deep eutectic solvents
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The multi-gram synthesis of a wide range of 1,2,3-Triazolines via azide-Alkene cycloaddition reactions in a Deep Eutectic Solvent (DES) is reported. The role of DES in this transformation as well as the origin of the full product distribution was studied with an experimental/computational-DFT approach.
- Sebest, Filip,Casarrubios, Luis,Rzepa, Henry S.,White, Andrew J. P.,Díez-González, Silvia
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supporting information
p. 4023 - 4035
(2018/09/11)
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- Copper-Catalyzed Decarboxylative/Click Cascade Reaction: Regioselective Assembly of 5-Selenotriazole Anticancer Agents
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A simple and efficient Cu-catalyzed decarboxylative/click reaction for the preparation of 1,4-disubstituted 5-arylselanyl-1,2,3-triazoles from propiolic acids, diselenides, and azides has been developed. The mechanistic study revealed that the intermolecular AAC reaction of an alkynyl selenium intermediate occurred. The resulting multisubstituted 5-seleno-1,2,3-triazoles were tested for in vitro anticancer activity by MTT assay, and compounds 4f, 4h, and 4p showed potent cancer cell-growth inhibition activities.
- Cui, Fei-Hu,Chen, Jing,Mo, Zu-Yu,Su, Shi-Xia,Chen, Yan-Yan,Ma, Xian-Li,Tang, Hai-Tao,Wang, Heng-Shan,Pan, Ying-Ming,Xu, Yan-Li
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supporting information
p. 925 - 929
(2018/02/22)
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- Selective synthesis of mono- and di-methylated amines using methanol and sodium azide as C1 and N1 sources
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A Ru(ii) complex mediated synthesis of various N,N-dimethyl and N-monomethyl amines from organic azides using methanol as a methylating agent is reported. This methodology was successfully applied for a one-pot reaction of bromide derivatives and sodium azide in methanol. Notably, by controlling the reaction time several N-monomethylated and N,N-dimethylated amines were synthesized selectively. The practical applicability of this tandem process was revealed by preparative scale reactions with different organic azides and synthesis of an anti-vertigo drug betahistine. Several kinetic experiments and DFT studies were carried out to understand the mechanism of this transformation.
- Chakrabarti, Kaushik,Mishra, Anju,Panja, Dibyajyoti,Paul, Bhaskar,Kundu, Sabuj
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supporting information
p. 3339 - 3345
(2018/07/29)
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- DIALKYLCARBOXYLATE-AROMATIC-FUNCTIONALIZED POLYMERS THAT DO NOT RELEASE ENDOCRINE DISRUPTING COMPOUNDS
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Disclosed are novel phthalate compounds and a simple and economical route to covalently attach a phthalate ester mimic to PVC is described, allowing plasticization of PVC without the danger of Endocrine Disruption Chemicals leaching from the polymer matri
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- Novel leucine ureido derivatives as aminopeptidase N inhibitors using click chemistry
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The over-expression of aminopeptidase N on diverse malignant cells is associated with the tumor angiogenesis and metastasis. In this report, one new series of leucine ureido derivatives containing the triazole moiety was designed, synthesized and evaluated as APN inhibitors. Among them, compound 13v showed the best APN inhibition with an IC50 value of 0.089 ± 0.007 μM, which was two orders of magnitude lower than that of bestatin (IC50 = 9.4 ± 0.5 μM). Compound 13v also showed dose-dependent anti-angiogenesis activities. Even at the lower concentration (10 μM), compound 13v presented similar anti-angiogenesis activity compared with bestatin at 100 μM in both the human umbilical vein endothelial cells (HUVECs) capillary tube formation assay and the rat thoracic aorta rings test. Moreover, compared with bestatin, 13v exhibited comparable, if not better in vivo anti-metastasis activity in a mouse H22 pulmonary metastasis model.
- Cao, Jiangying,Ma, Chunhua,Zang, Jie,Gao, Shuai,Gao, Qianwen,Kong, Xiujie,Yan, Yugang,Liang, Xuewu,Ding, Qin'ge,Zhao, Chunlong,Wang, Binghe,Xu, Wenfang,Zhang, Yingjie
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p. 3145 - 3157
(2018/06/01)
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- Ruthenium Bisammine Complex and Its Reaction with Aryl Azides
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A ruthenium bisammine complex was formed in the reaction of ruthenium 1,4-dibenzyltetraazadiene complex with primary amines at room temperature, which was a versatile precursor for the synthesis of various Ru(II) complexes through ligand exchange reactions. In the reaction with azidobenzene, ruthenium 1,4-diphenyltetraaza-1,3-diene complex was formed, while ruthenium imido complexes were given in the reaction with bulky aryl azides such as 2-azido-1,3-dimethylbenzene and 2-azido-1,3-diisopropylbenzene. The ruthenium imido complexes showed high catalytic activity in the reaction of alkyl azides with primary amines to afford N-substituted imines.
- Park, Jin Yong,Kim, Yongjin,Bae, Dae Young,Rhee, Young Ho,Park, Jaiwook
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supporting information
p. 3471 - 3476
(2017/10/03)
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- B(C6F5)3-catalyzed synthesis of benzylic azides
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B(C6F5)3 was found to catalyze the reaction between trimethylsilyl azide and benzylic acetates. Secondary and tertiary benzylic acetates were competent substrates in this reaction providing the azide products in moderate t
- Wrigley, Michael S.,Barker, Timothy J.
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p. 1771 - 1776
(2017/09/23)
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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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- Small Molecule Microarray Based Discovery of PARP14 Inhibitors
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Poly(ADP-ribose) polymerases (PARPs) are key enzymes in a variety of cellular processes. Most small-molecule PARP inhibitors developed to date have been against PARP1, and suffer from poor selectivity. PARP14 has recently emerged as a potential therapeutic target, but its inhibitor development has trailed behind. Herein, we describe a small molecule microarray-based strategy for high-throughput synthesis, screening of >1000 potential bidentate inhibitors of PARPs, and the successful discovery of a potent PARP14 inhibitor H10 with >20-fold selectivity over PARP1. Co-crystallization of the PARP14/H10 complex indicated H10 bound to both the nicotinamide and the adenine subsites. Further structure–activity relationship studies identified important binding elements in the adenine subsite. In tumor cells, H10 was able to chemically knockdown endogenous PARP14 activities.
- Peng, Bo,Thorsell, Ann-Gerd,Karlberg, Tobias,Schüler, Herwig,Yao, Shao Q.
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supporting information
p. 248 - 253
(2016/12/30)
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- Fused Bicyclic Caspase-1 Inhibitors Assembled by Copper-Free Strain-Promoted Alkyne–Azide Cycloaddition (SPAAC)
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Challenges exist in the development of potent and selective small-molecule inhibitors against caspase-1. Herein, by making use of the copper-free strain-promoted alkyne–azide cycloaddition (SPAAC) reaction between difluorinated cyclooctynes (DIFOs) and va
- Qian, Linghui,Zhang, Chong-Jing,Wu, Ji'en,Yao, Shao Q.
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supporting information
p. 360 - 369
(2017/01/17)
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- Copper complexes bearing an NHC-calixarene unit: Synthesis and application in click chemistry
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The synthesis of N-heterocyclic carbene (NHC) copper complexes supported by calix[4]arene is reported. Mono-substituted calix[4]arene was prepared through conventional procedures, followed by the attachment of an imidazolyl group to create the precursor o
- Ourri, Benjamin,Tillement, Olivier,Tu, Tao,Jeanneau, Erwann,Darbost, Ulrich,Bonnamour, Isabelle
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p. 9477 - 9485
(2016/11/11)
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- METHOD OF CONVERTING ALCOHOL TO HALIDE
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The present invention relates to a method of converting an alcohol into a corresponding halide. This method comprises reacting the alcohol with an optionally substituted aromatic carboxylic acid halide in presence of an N-substituted formamide to replace a hydroxyl group of the alcohol by a halogen atom. The present invention also relates to a method of converting an alcohol into a corresponding substitution product. The second method comprises: (a) performing the method of the invention of converting an alcohol into the corresponding halide; and (b) reacting the corresponding halide with a nucleophile to convert the halide into the nucleophilic substitution product.
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Page/Page column 56; 150; 154
(2017/01/02)
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- Highly selective direct azidation of alcohols over a heterogeneous povidone-phosphotungstic solid acid catalyst
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A simple protocol for the selective azidation of alcohols is developed using a solid acid hybrid of a povidone and phosphotungstic acid (PVP-PWA) using azidotrimethylsilane as an azide source at room temperature. In a broad substrate scope, various activated as well as unactivated benzylic and diphenyl alcohols were treated smoothly with TMS-N3 to selectively produce only azide products with excellent yields in a very short reaction time of 2 h. FT-IR confirmed the stability of the catalyst with retention of the Keggins structure after the reaction. Recycling experiments demonstrated the reusability of the PVP-PWA (3?:?1) several times without losing its original activity.
- Kamble, Sumit,More, Sagar,Rode, Chandrashekhar
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p. 10240 - 10245
(2016/12/06)
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- Benzylic C-H Azidation Using the Zhdankin Reagent and a Copper Photoredox Catalyst
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An azidation method for C-N bond formation at benzylic C-H positions is described using copper-catalyzed visible light photochemistry and the Zhdankin azidoiodinane reagent. The method is applicable to a wide range of substrates bearing different functional groups and having a primary, secondary, or tertiary benzylic position, and is thought to proceed through a radical chain reaction.
- Rabet, Pauline T. G.,Fumagalli, Gabriele,Boyd, Scott,Greaney, Michael F.
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supporting information
p. 1646 - 1649
(2016/04/26)
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- Synthesis of Sulfonyl Azides via Lewis Base Activation of Sulfonyl Fluorides and Trimethylsilyl Azide
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A protocol for the efficient conversion of sulfonyl fluorides into sulfonyl azides through Lewis base activation is described. The in situ generated sulfonyl azides are efficient diazo-transfer agents, affording diazo compounds and primary azides in excellent yields.
- Barrow, Andrew S.,Moses, John E.
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supporting information
p. 1840 - 1843
(2016/07/16)
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- Palladium-catalyzed cross-coupling reaction of azides with isocyanides
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An efficient palladium-catalyzed cross-coupling reaction of azides with isocyanides is developed, providing a general synthetic route to unsymmetric carbodiimides with excellent yields. This method shows a broad substrate scope, including not only aryl azides, but also unactivated benzyl and alkyl azides. Furthermore, from readily available substrates, Pd-catalyzed coupling with a tandem amine insertion cascade to obtain unsymmetric trisubstituted guanidines has been achieved in a one-pot fashion.
- Zhang, Zhen,Li, Zongyang,Fu, Bin,Zhang, Zhenhua
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supporting information
p. 16312 - 16315
(2015/11/16)
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- A straightforward and versatile approach to the synthesis of 1,4,5-trisubstituted 1,2,3-triazoles from alkyl halides via a one-pot, three-component reaction
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The preparation of 1,4,5-trisubstituted 1,2,3-triazoles by the coupling of three components (alkyl halides, sodium azide, and active ketones) through an azide-enolate [3+2] cycloaddition (Dimroth cycloaddition) has been developed for the first time. A wide variety of halides (including chlorides, bromides, and iodides as well as primary and secondary derivatives) have demonstrated the versatility of this method, which is based on a one-pot system under mild reaction conditions.
- González-Calderón, Davir,Aguirre-De Paz, José G.,González-González, Carlos A.,Fuentes-Benítes, Aydeé,González-Romero, Carlos
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p. 1713 - 1715
(2015/03/14)
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- Metal-catalysed azidation of tertiary C-H bonds suitable for late-stage functionalization
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Many enzymes oxidize unactivated aliphatic C-H bonds selectively to form alcohols; however, biological systems do not possess enzymes that catalyse the analogous aminations of C-H bonds. The absence of such enzymes limits the discovery of potential medicinal candidates because nitrogen-containing groups are crucial to the biological activity of therapeutic agents and clinically useful natural products. In one prominent example illustrating the importance of incorporating nitrogen-based functionality, the conversion of the ketone of erythromycin to the -N(Me)CH2 - group in azithromycin leads to a compound that can be dosed once daily with a shorter treatment time. For such reasons, synthetic chemists have sought catalysts that directly convert C-H bonds to C-N bonds. Most currently used catalysts for C-H bond amination are ill suited to the intermolecular functionalization of complex molecules because they require excess substrate or directing groups, harsh reaction conditions, weak or acidic C-H bonds, or reagents containing specialized groups on the nitrogen atom. Among C-H bond amination reactions, those forming a C-N bond at a tertiary alkyl group would be particularly valuable, because this linkage is difficult to form from ketones or alcohols that might be created in a biosynthetic pathway by oxidation. Here we report a mild, selective, iron-catalysed azidation of tertiary C-H bonds that occurs without excess of the valuable substrate. The reaction tolerates aqueous environments and is suitable for the functionalization of complex structures in the late stages of a multistep synthesis. Moreover, this azidation makes it possible to install a range of nitrogen-based functional groups, including those from Huisgen 'click' cycloadditions and the Staudinger ligation. We anticipate that these reactions will create opportunities to modify natural products, their precursors and their derivatives to produce analogues that contain different polarity and charge as a result of nitrogen-containing groups. It could also be used to help identify targets of biologically active molecules by creating a point of attachment - for example, to fluorescent tags or 'handles' for affinity chromatography - directly on complex molecular structures.
- Sharma, Ankit,Hartwig, John F.
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p. 600 - 604
(2015/03/04)
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- Convenient and direct azidation of sec -benzyl alcohols by trimethylsilyl azide with bismuth(III) triflate catalyst
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Sec-Benzyl azides were efficiently prepared by bismuth(III)-catalyzed direct azidation of sec-benzyl alcohols. The reaction was applied to a variety of substrates to provide the desired products in up to 99% yield within a short reaction time.
- Tummatorn, Jumreang,Thongsornkleeb, Charnsak,Ruchirawat, Somsak,Thongaram, Phanida,Kaewmee, Benyapa
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p. 323 - 329
(2015/02/19)
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- Exploiting the Nucleophilicity of N-H Imines: Synthesis of Enamides from Alkyl Azides and Acid Anhydrides
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The nucleophilicity of N-unsubstituted imines, which were generated from alkyl azides by a ruthenium-catalyzed reaction, was investigated in the reaction with acid anhydrides. The initial products were N-acylimines, which isomerized to the corresponding e
- Han, Junghoon,Jeon, Mina,Pak, Han Kyu,Rhee, Young Ho,Park, Jaiwook
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supporting information
p. 2769 - 2774
(2016/02/18)
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- Modular o-quinone catalyst system for dehydrogenation of tetrahydroquinolines under ambient conditions
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Quinolines are common pharmacophores present in numerous FDA-approved pharmaceuticals and other bioactive compounds. Here, we report the design and development of new o-quinone-based catalysts for the oxidative dehydrogenation of tetrahydroquinolines to afford quinolines. Use of a Co(salophen) cocatalyst allows the reaction to proceed efficiently with ambient air at room temperature. The utility of the catalytic method is demonstrated in the preparation of a number of medicinally relevant quinolines.
- Wendlandt, Alison E.,Stahl, Shannon S.
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supporting information
p. 11910 - 11913
(2014/10/16)
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- Facile synthesis of 1-Alkoxy-1H-benzo- and 7-azabenzotriazoles from peptide coupling agents, mechanistic studies, and synthetic applications
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(1H-Benzo[d][1,2,3]triazol-1-yloxy)tris(dimethylamino)phosphonium hexafluorophosphate (BOP), 1H-benzo[d][1,2,3]triazol-1-yl 4- methylbenzenesulfonate (Bt-OTs), and 3H-[1,2,3]triazolo[4,5-b]pyridine-3-yl 4-methylbenzenesulfonate (At-OTs) are classically utilized in peptide synthesis for amide-bond formation. However, a previously undescribed reaction of these compounds with alcohols in the presence of a base, leads to 1-alkoxy-1H-benzo- (Bt-OR) and 7-azabenzotriazoles (At-OR). Although BOP undergoes reactions with alcohols to furnish 1-alkoxy-1H-benzotriazoles, Bt-OTs proved to be superior. Both, primary and secondary alcohols undergo reaction under generally mild reaction conditions. Correspondingly, 1-alkoxy-1H-7-azabenzotriazoles were synthesized from At-OTs. Mechanistically, there are three pathways by which these peptide-coupling agents can react with alcohols. From 31P{1H}, [18O]-labeling, and other chemical experiments, phosphonium and tosylate derivatives of alcohols seem to be intermediates. These then react with BtO- and AtO- produced in situ. In order to demonstrate broader utility, this novel reaction has been used to prepare a series of acyclic nucleoside-like compounds. Because BtO- is a nucleofuge, several Bt-OCH2Ar substrates have been evaluated in nucleophilic substitution reactions. Finally, the possible formation of Pd πallyl complexes by departure of BtO- has been queried. Thus, alpha-allylation of three cyclic ketones was evaluated with 1-(cinnamyloxy)-1H-benzo[d][1,2,3]triazole, via in situ formation of pyrrolidine enamines and Pd catalysis.
- Lakshman, Mahesh K.,Singh, Manish K.,Kumar, Mukesh,Chamala, Raghu Ram,Yedulla, Vijayender R.,Wagner, Domenick,Leung, Evan,Yang, Lijia,Matin, Asha,Ahmad, Sadia
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supporting information
p. 1919 - 1932
(2014/11/07)
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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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- Synthesis of 2,4-unsubstituted quinoline-3-carboxylic acid ethyl esters from arylmethyl azides via a domino process
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A convenient synthesis of 2,4-unsubstituted quinoline-3-carboxylic acid ethyl esters via a domino process is described. The synthesis employs arylmethyl azides as the precursor which undergoes an acid-promoted rearrangement to give an N-aryl iminium ion. Following the addition with ethyl 3-ethoxyacrylate, intramolecular electrophilic aromatic substitution, elimination and subsequent oxidation, the quinoline products were obtained in moderate to excellent yields.
- Tummatorn, Jumreang,Thongsornkleeb, Charnsak,Ruchirawat, Somsak,Gettongsong, Tanita
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supporting information
p. 1463 - 1467
(2013/05/08)
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- Reusable and highly active supported copper(i)-NHC catalysts for Click chemistry
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Immobilised [Cu(NHC)] catalysts are reported for the preparation of 1,2,3-triazoles. In addition to showing outstanding catalytic activity, the catalyst systems are easy to prepare and can be recycled many times.
- Collinson, John-Michael,Wilton-Ely, James D. E. T.,Diez-Gonzalez, Silvia
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supporting information
p. 11358 - 11360
(2013/12/04)
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- Mesoionic carbene-boranes
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Mesoionic carbenes (MICs), derived from alkylation and deprotonation of triazoles, are shown to form stable complexes with BH3. The synthesis of triazoles via Huigsen cycloadditions provides considerable structural diversity. Several routes to MIC-boranes are described, and their structures have been characterized by X-ray crystallography. As predicted on the basis of the increased σ-donor capacity of MICs by comparison to NHCs, the MIC-borane adducts are more reactive reducing agents.
- De Oliveira Freitas, Luiza Baptista,Eisenberger, Patrick,Crudden, Cathleen M.
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supporting information
p. 6635 - 6638
(2014/01/06)
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- Iron-catalyzed chemoselective azidation of benzylic silyl ethers
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Azidation: Siloxy groups derived from secondary and tertiary benzyl alcohols can be transformed into azide groups at room temperature using TMSN3 in the presence of an iron catalyst (see scheme; TMS=trimethylsilyl). Secondary and tertiary benzy
- Sawama, Yoshinari,Nagata, Saori,Yabe, Yuki,Morita, Kosuke,Monguchi, Yasunari,Sajiki, Hironao
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supporting information
p. 16608 - 16611
(2013/03/13)
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- Reaction pathway and rate-determining step of the Schmidt rearrangement/fragmentation: A kinetic study
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The Schmidt rearrangement of substituted 3-phenyl-2-butanone with trimethylsilyl azide in 90% (v/v) aqueous TFA gave two types of product, fragmentation and rearrangement, the ratio of which depends on the substituent: more fragmentation for a more electron-donating substituent. Rate measurements by azotometry indicated the presence of an induction period, and the pseudo-first-order rate constants showed saturation kinetics with respect to the azide concentration. It was indicated that the reaction proceeds through pre-equilibrium in the formation of iminodiazonium (ID) ion and that the N 2 liberation from the ID ion is rate-determining. Under high azide concentration conditions, where the effective reactant is the ID ion, the reaction gave a linear Hammett plot with a value of -0.50. The observed substituent effects on the rate and the product selectivity imply that path bifurcation on the way from the rate-determining TS to the product states occurs, as suggested by previous molecular dynamics simulations, in a similar manner to the analogous Beckmann rearrangement/fragmentation reactions.
- Akimoto, Ryo,Tokugawa, Takehiro,Yamamoto, Yutaro,Yamataka, Hiroshi
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experimental part
p. 4073 - 4078
(2012/06/29)
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- FeCl3-catalyzed addition of nitrogen and 1,3-dicarbonyl nucleophiles to olefins
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A direct intermolecular addition of nitrogen and 1,3-dicarbonyl nucleophiles to stabilized double bonds (styrenes, 1,3-dienes, enol-ethers, sugars.) in the presence of green and inexpensive FeCl3 catalyst is described.
- Zotto, Christophe Dal,Michaux, Julien,Zarate-Ruiz, Araceli,Gayon, Eric,Virieux, David,Campagne, Jean-Marc,Terrasson, Vincent,Pieters, Grégory,Gaucher, Anne,Prim, Damien
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experimental part
p. 296 - 304
(2011/02/17)
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- Oxidative nucleophilic substitution: Transformation of alkylboronic derivatives
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An efficient amidation reaction is described in this paper. Potassium alkyltrifluoroborate salts can be transforming to amides from nitriles in the presence of copper acetate and boron trifluoride. An extension of this reaction allowed the formation of amines, ethers, and C-C bond.
- Cazorla, Clément,Métay, Estelle,Lemaire, Marc
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p. 8615 - 8621
(2011/11/30)
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- A Lewis acid mediated schmidt reaction of benzylic azide: Synthesis of sterically crowded aromatic tertiary amines
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An efficient one-pot synthesis of sterically hindered aromatic tertiary amines through Lewis acid induced intermolecular Schmidt reaction of benzylic azides is described. In the presence of EtAlCl2, benzylic azide underwent a smooth Schmidt reaction to give the corresponding iminium ion, which, upon reduction with NaBH4 in situ, afforded the tertiary amine. The effects of substituents on the aromatic ring and the steric effects of the alkyl side chain have also been studied.
- Murali, Annamalai,Puppala, Manohar,Varghese, Babu,Baskaran, Sundarababu
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supporting information; experimental part
p. 5297 - 5302
(2011/11/12)
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- Fe(OTf)3-catalyzed reaction of benzylic acetates with organosilicon compounds
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Fe(OTf)3-catalyzed reaction of benzylic acetates with allyltrimethylsilane, azidotrimethylsilane, and cyanotrimethylsilane afforded the corresponding allylated, azido, and cyano products in high yields. 2-Trimethylsilyl-substituted benzofuran and indole worked well to furnish the benzyl-substituted benzofuran and indoles. Georg Thieme Verlag Stuttgart New York.
- Chan, Li Yan,Kim, Sundae,Chung, Wan Ting,Long, Chong,Kim, Sunggak
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experimental part
p. 415 - 419
(2011/04/22)
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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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- Boronic acid catalysis for mild and selective [3+2] dipolar cycloadditions to unsaturated carboxylic acids
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Herein, the concept of boronic acid catalysis (BAC) for the activation of unsaturated carboxylic acids is applied in several classic dipolar [3 + 2] cycloadditions involving azides, nitrile oxides, and nitrones as partners. These cycloadditions can be used to produce pharmaceutically interesting, small heterocyclic products, such as triazoles, isoxazoles, and isoxazolidines. These cycloadducts are formed directly and include a free carboxylic acid functionality that can be employed for fur-ther transformations, thereby avoiding prior masking or functionalization. In all cases, BAC provides faster reactions, under milder conditions, with much improved product yields and regioselectivities. In some instances, such as triazole formation from the reaction of azides with 2-alkynoic acids, catalysis with ort/io- nitrophenylboronic acid circumvents the undesirable product decarboxylation observed when using thermal activation. By using NMR spectroscopic studies, the boronic acid catalyst was shown to provide activation by a LUMO-lowering effect in the unsaturated carboxylic acid, likely via a monoacylated hemiboronic ester intermediate.
- Zheng, Hongchao,McDonald, Robert,Hall, Dennis G.
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supporting information; experimental part
p. 5454 - 5460
(2010/09/15)
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- A chemoselective aerobic oxidation of benzylic azides catalyzed by molybdenum xanthate in an aqueous medium
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A mild molybdenum-catalyzed, aerobic, chemoselective oxidation of benzylic azides to the corresponding aldehydes in an aqueous medium that tolerates a variety of functional groups including alcohols, esters, ketones, halides and olefins is described.
- Maddani, Mahagundappa,Prabhu, Kandikere Ramaiah
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p. 4526 - 4530
(2008/09/21)
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- CINNAMOYL INHIBITORS OF TRANSGLUTAMINASE
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A compound of Formula, (I) or Formula: (II)
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Page/Page column 53; 79
(2009/01/20)
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- Intermodular FeCl3-catalyzed hydroamination of styrenes
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Hydroamination reactions of vinylarenes with nonnucleophilic nitrogen derivatives (p-toluenesulfonamide, p-nitroaniline, p-nitrobenzamide, ...) catalyzed by FeCl3 are described. Interestingly, these reactions are catalyzed by an environmentally
- Michaux, Julien,Terrasson, Vincent,Marque, Sylvain,Wehbe, Johny,Prim, Damien,Campagne, Jean-Marc
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p. 2601 - 2603
(2008/02/06)
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- Copper(II) triflate as a double catalyst for the one-pot click synthesis of 1,4-disubstituted 1,2,3-triazoles from benzylic acetates
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Copper(II) triflate doubly catalyzed the substitution of benzylic acetates by TMSN3 and the subsequent 1,3-dipolar addition with an alkyne in one pot. This procedure afforded the preparation of 1,4-disubstituted 1,2,3-triazoles in good yields starting from the easily accessible acetates without isolating an organic azide using a single catalyst. Georg Thieme Verlag Stuttgart.
- Fukuzawa, Shin-Ichi,Shimizu, Eiji,Kikuchi, Satoshi
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p. 2436 - 2438
(2008/03/28)
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- Triphenylphosphine/2,3-dichloro-5,6-dicyanobenzoquinone in the presence of n-Bu4NN3 is a useful system for efficient conversion of tetrahydropyranyl (THP) ethers to their corresponding alkyl azides
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Triphenylphosphine/2,3-dichloro-5,6-dicyanobenzoquinone/tetrabutylammonium azide was used as an efficient system in conversion of tetrahydropyranyl ethers to corresponding alkyl azides. Copyright Taylor & Francis Inc.
- Akhlaghinia, Batool
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p. 1601 - 1604
(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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