- NFSI/KF mediated mild and chemoselective interconversion of aryl TBDMS ethers to their benzene sulfonate
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A one pot protocol for the transformation of aryl TBDMS ethers to corresponding benzene sulfonate esters using NFSI (N-flurobenzenesulfonimide)/KF is described. In situ generation of benzenesulfonyl fluoride directs chemoselective cleavage of aryl silyl ethers over alkyl silyl ethers. Electron withdrawing substituent's on aryl ring provided better yield than donating groups. Protecting groups and sensitive functionalities are well tolerated in this methodology. Thus, commercially available inexpensive reagents, mild reaction conditions and step economy are the advantages of this method.
- Dond, Bharat D.,Thore, Shivaji N.
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supporting information
(2020/02/06)
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- Synthesis of phenols and aryl silyl ethers via arylation of complementary hydroxide surrogates
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Two transition-metal-free methods to access substituted phenols via the arylation of silanols or hydrogen peroxide with diaryliodonium salts are presented. The complementary reactivity of the two nucleophiles allows synthesis of a broad range of phenols without competing aryne formation, as illustrated by the synthesis of the anesthetic Propofol. Furthermore, silyl-protected phenols can easily be obtained, which are suitable for further transformations.
- Reitti, Marcus,Gurubrahamam, Ramani,Walther, Melanie,Lindstedt, Erik,Olofsson, Berit
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p. 1785 - 1788
(2018/04/14)
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- Metal-free deoxygenation and reductive disilylation of nitroarenes by organosilicon reducing reagents
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A metal-free deoxygenation and reductive disilylation of nitroarenes was achieved using N,N’-bis(trime-thylsilyl)-4,4’-bipyridinylidene (1) under mild and neutral reaction conditions, and a broad functional group tolerance was possible in this reaction. Mono-deoxygenation, giving a synthetically valuable N,O-bis(trimethylsilyl)phe-nylhydroxylamine (7a) as a readily available and safe phenylnitrene source from nitrobenzene, and double-deoxy-genation, giving N,N-bis(trimethylsilyl)anilines 8, were easily controlled by varying the amounts of 1 and reaction temperature as well as adding dibenzothiophene (DBTP). Reaction of 2-arylnitrobenzenes with 1 resulted in the formation of the corresponding carbazoles 14 via in situ-gen-erated phenylnitrene species derived by thermolysis of N,O-bis(trimethylsilyl)phenylhydroxylamines 7, followed by their subsequent intramolecular C H insertion. In addition, the intramolecular N N coupling reaction proceeded in the reduction of 2,2’-dinitrobiphenyl derivatives by 1, giving the corresponding benzo[c]cinnolines.
- Bhattacharjee, Argha,Hosoya, Hiromu,Ikeda, Hideaki,Nishi, Kohei,Tsurugi, Hayato,Mashima, Kazushi
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supporting information
p. 11278 - 11282
(2018/10/20)
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- Tert-Butyldimethylsilyl Amine (TBDMS-NH2): A Mild and Green Reagent for the Protection of Benzyl Alcohols, Phenols, and Carboxylic Acids under Solvent-Free Conditions
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Herein, we present the use of the tert-butyldimethylsilyl amine (TBDMS-NH2) as a silylating reagent for phenols, benzyl alcohols, and carboxylic acids. Unlike other silyl protection reactions, this reported process with TBDMS-NH2 does not involve the form
- Duczynski, Jeremy A.,Fuller, Rebecca,Stewart, Scott G.
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p. 1172 - 1179
(2016/10/13)
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- An efficient and chemoselective deprotection of aryl tert-butyldimethylsilyl (TBDMS) ethers by NaCN
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Phenolic tert-butyldimethylsilyl (TBDMS) ethers can be deprotected to yield phenols in excellent yield using sodium cyanide (NaCN) as catalyst in ethanol. The deprotectation of various phenolic TBDMS ethers were found to be very convenient, fast, high yielding and chemoselective.
- Qiao, Xue-Jun,Hou, Xiao,Fang, Wu-Hong,Bao, Xue-Fei,Chen, Guo-Liang
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p. 899 - 904
(2016/05/19)
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- Preparation of nano silica supported sodium hydrogen sulfate: As an efficient catalyst for the trimethyl, triethyl and t-butyldimethyl silylations of aliphatic and aromatic alcohols in solution and under solvent-free conditions
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Nano silica supported sodium hydrogen sulfate has been prepared by mixing NaHSO4 with activated Nano silicagel. We wish to report a new method for the synthesis of trimethyl (TMS), triethyl (TES) and t-butyldimethyl silyl (TBS) ethers from benzylic, allylic, propargylic alcohols, phenols, naphtholes and some of phenolic drugs in the solution and under solvent-free conditions.
- Abri, Abdolreza,Ranjdar, Somayeh
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p. 929 - 934
(2014/10/16)
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- Ipso-nitration of arylboronic acids with bismuth nitrate and perdisulfate
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An efficient and one pot synthetic method of ipso-nitration of arylboronic acids has been developed. The high efficiency, general applicability, and broader substrate scope including heterocycles and functional groups make this method advantageous. Due to its simplicity, we expect to find application of this method in synthesis.
- Manna, Srimanta,Maity, Soham,Rana, Sujoy,Agasti, Soumitra,Maiti, Debabrata
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supporting information; experimental part
p. 1736 - 1739
(2012/05/20)
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- A mild and highly efficient method for the preparation of silyl ethers using Fe(HSO4)3/Et3N by chlorosilanes
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Avery efficient and mild procedure for preparation of silyl ethers from benzylic, allylic, propargilic alcohols, phenols, naphtoles and some of phenolic drugs with trimethylsilylchloride (TMSCl), triethylsilylchloride (TESCl) and t-buthyldimethylsilyl chloride (TDSCl) ethers in the presence of Fe(HSO 4)3/Et3N in roomtemperature in excellent yields is reported. This procedure also allows the excellent selectivity for silylation of alcohols and phenols.
- Abri, Abdolreza,Assadi, Mohammad Galeh,Pourreza, Samira
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p. 1449 - 1454
(2013/03/13)
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- THERAPEUTIC AGENT FOR HEPATITIS C
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This invention provides a therapeutic agent for hepatitis C comprising, as an active ingredient, a compound having anti-HCV activity useful in treatment of hepatitis C. The therapeutic agent for hepatitis C comprises, as an active ingredient, a compound represented by formula (I) or a pharmaceutically acceptable salt thereof.
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Page/Page column 21
(2013/02/27)
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- The effect of solvent accessible surface on Hammett-type dependencies of infinite dilution 29Si and 13C NMR shifts in ring substituted silylated phenols dissolved in chloroform and acetone
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Infinite dilution 29Si and 13C NMR chemical shifts were determined from concentration dependencies of the shifts in dilute chloroform and acetone solutions of para substituted O-silylated phenols, 4-R-C6H4-O-SiR′2R″ (R = Me, MeO, H, F, Cl, NMe2, NH2, and CF3), where the silyl part included groups of different sizes: dimethylsilyl (R′ = Me, R″ = H), trimethylsilyl (R′ = R″ = Me), tert-butyldimethylsilyl (R′ = Me, R″ = CMe3), and tert-butyldiphenylsilyl (R′ = C6H5, R″ = CMe3). Dependencies of silicon and C-1 carbon chemical shifts on Hammett substituent constants are discussed. It is shown that the substituent sensitivity of these chemical shifts is reduced by association with chloroform, the reduction being proportional to the solvent accessible surface of the oxygen atom in the Si-O-C link. Copyright
- Blechta, Vratislav,Sabata, Stanislav,Sykora, Jan,Hetflejs, Jiri,Soukupova, Ludmila,Schraml, Jan
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experimental part
p. 128 - 134
(2012/08/07)
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- Novel steroid mimics directed towards the estradiol skeleton
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A series of non-symmetrical tri- and tetra-substituted ureas have been prepared to mimic the rigid tetracyclic core of estradiol. Tetra-substituted ureas were prepared by a five-step protocol, involving activation and displacement of a carbonyldiimidazole
- Bridgeman, Eve,Cavill, Julie L.,Schofield, Daniel J.,Wilkins, Derek S.,Tomkinson, Nicholas C. O.
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p. 8521 - 8524
(2007/10/03)
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- An Effective Approach for the Silylation of Hydroxyl Compounds in Room Temperature Ionic Liquids
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The room temperature ionic liquid (RTIL) 1-n-butyl-3-methylimidazolium hexafluorophosphate (BMImPF6) is used as a "green" recyclable alternative to conventional solvents for the silylation of a series of hydroxyl compounds (alcohols and phenols
- Xu, Zhen-Yuan,Xu, Dan-Qian,Liu, Bao-You,Luo, Shu-Ping
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p. 4143 - 4149
(2007/10/03)
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- 4-HYDROXY-PIPERODINE DERIVATIVES
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The present invention relates to compounds of the formula STR1 wherein x is--O--,--NH--,--CH 2--,--CH=,--CO 2--,--CONH--,--CON(lower alkyl)--,--S--and--SO 2--; R. sup.1-R. sup.4 are, independently from each other hydrogen, halogen, hydroxy, amino, nitro, lower-alkyl-sulfonylamido, 1-or 2-imidazolyl, 1-(1,2,4-triazolyl) or acetamido;R 5, R 6 are, independently from each other hydrogen, lower-alkyl, hydroxy, lower alkoxy or oxo;R. sup.7-R 10 are, independently from each other hydrogen, lower-alkyl, halogen, trifluoromethyl or lower-alkoxy;n is 0 or 1; and to pharmaceutically acceptable acid addition salts thereof. Compounds of the present invention are NMDA(N-methyl-D-aspartate)-receptor subtype selective blockers.
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- Polymer-supported reactions in organic synthesis: Part 1 - Protection and deprotection of phenols using anion exchange resin.
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Phenoxide ions supported on Amberlite IRA-400 (chloride form) are protected as t-butyl(dimethyl)silyl (TBDMS) ethers in good to excellent yields and subsequently deprotected by fluoride ions supported on Amberlite IRA-400 (chloride form).
- Bandgar, B. P.,Unde, S. D.,Unde, D. S.,Kulkarni, V. H.,Patil, S. V.
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p. 782 - 784
(2007/10/03)
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