- Chemoselective, Isomerization-Free Synthesis of N-Acylketimines from N–H Imines
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N-Acylketimines were synthesized through a ruthenium-catalyzed generation of N–H ketimines from secondary azides and subsequent acylation with mixed anhydrides under mild conditions. The synthetic scope was broad to give N-acylimines having various functi
- Kwon, Yearang,Rhee, Young Ho,Park, Jaiwook
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supporting information
p. 1503 - 1507
(2017/05/05)
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- Copper triflate: An efficient catalyst for direct conversion of secondary alcohols into azides
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A simple, practical, and efficient strategy has been demonstrated for the direct synthesis of organic azides from alcohols using azidotrimethylsilane (TMSN3) as azide source in the presence of copper(II) triflate [Cu(OTf)2]. A variet
- Khedar, Poonam,Pericherla, Kasiviswanadharaju,Kumar, Anil
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supporting information
p. 515 - 518
(2014/03/21)
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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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- 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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- TACHYKININ RECEPTOR ANTAGONISTS
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The present invention relates to selective NK-1 receptor antagonists of Formula (I) or a pharmaceutically acceptable salt thereof, for the treatment of disorders associated with an excess of tachykinins.
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- Concerted Bimolecular Substitution Reactions of 1-Phenylethyl Derivatives
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Substituted 1-phenylethyl derivatives with ?+ > -0.08 exhibit bimolecular substitution reactions with azide ion in 20percent acetonitrile in water.The reactions with 1-phenylethyl chlorides follow a Hammett correlation with ρ = -2.9, compared with ρ = -5.6 (r+ = 1.15) for solvolysis.Swain-Scott correlations give values of s = 0.46 and 0.22 for 1-(4-nitrophenyl)ethyl chloride and tosylate, respectively; there are large positive deviations for azide ion and water and negative deviations for cyanide ion.The value of βnuc is 0.09 for reactions of substituted acetates with the chloride.The reactions exhibit ''synergism'' between the nucleophile and leaving group that favors the bimolecular reaction with Me2S, Br- > Cl- > OTs- leaving groups.The bimolecular reaction with azide follows the Grunwald-Winstein Y correlation with m = 0.8 in methanol-water mixtures.Bimolecular reactions with less reactive nucleophiles in the series N3-, CN-, AcO-, and ROH appear at progressively larger ? values, as the carbocation becomes less stable.It is concluded that these reactions are SN2 displacements that proceed through an open, ''exploded'' transition state that closely resembles a carbocation.Specific salt effects are small in water but are significant in acetonitrile-water mixtures and could be mistaken for normal or induced common ion rate depressions.No evidence was obtained for nucleophilic assistance to the formation of a carbocation intermediate.Concurrent SN1 and SN2 pathways occur in the reactions with solvent and azide of dimethylsulfonium ion, 1-(4-fluorophenyl)ethyl chloride, 1-(3-methoxyphenyl)ethyl chloride, and, probably, 1-(3-nitro-4-methoxyphenyl)ethyl chloride.Crude estimates of the lifetime of the carbocation intermediate in the presence of the nucleophile are consistent with the hypothesis that the concerted reactions are enforced by the absence of a significant lifetime of the carbocation in the presence of the nucleophile and that stepwise mechanisms are followed when the intermediate has a significant lifetime; the change from a stepwise to a concerted mechanism occurs when the intermediate ceases to have a lifetime in the presence of a nucleophile.
- Richard, John P.,Jencks, William P.
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p. 1383 - 1396
(2007/10/02)
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