87020-12-0Relevant articles and documents
Metal-free synthesis of quinolines by direct condensation of amides with alkynes: revelation of N-aryl nitrilium intermediates by 2D NMR techniques
Ye, Jian-Liang,Zhu, Ya-Nan,Geng, Hui,Huang, Pei-Qiang
, p. 687 - 694 (2018)
Employing triflic anhydride/2-fluoropyridine as an activation system, the coupling reactions of secondary N-aryl amides with terminal alkynes yielded substituted quinolines in moderate to excellent yields. The reaction tolerated both electron-donating and electron-withdrawing groups at the benzamide moiety. Electron-rich aryl acetylenes served as excellent coupling partners, and aliphatic terminal alkynes such as cyclopropyl and conjugate vinyl acetylenes could also be used as reaction partners. By means of 2D NMR techniques (heteronuclear multiple bond correlation (HMBC), heteronuclear single quantum correlation (HSQC)), nitrilium ions were probed as reactive intermediates which are in contrast with that suggested by Movassaghi on the basis of in situ IR monitoring experiments. On the basis of these results, a plausible mechanism for the formation of quinolines was suggested.
The Chemistry of Nitrilium Salts. Part 2. The Preparation of Nitrilium Trifluoromethanesulphonate Salts and Their Reactions with Some Oxygen and Sulphur Nucleophiles
Booth, Brian L.,Jibodu, Kehinde O.,Proenca, M. Fernanda J. R. P.
, p. 1067 - 1073 (2007/10/02)
The syntheses of the nitrilium salts NMe>+3SCF3 i, PhCH2, Ph, CH2=CHCH2, NC(CH2)3, and CH2=CH> by reaction of MeO3SCF3 with the corresponding nitriles are described. the similar reaction between (E)-PhCH=CHCN and MeO3SCF3 gives a mixture of NMe>+SCF3 and the s-triazinium salt 3C3N3H>+3SCF3, which hydrolyzes to give (E)-PhCH=CHCONHMe and the triazine.The compound CF3SO3(CH2)4CN, prepared from I(CH2)4CN and AgO3SCF3, does not form a cyclic nitrilium salt, but slowly dimerizes at room temperature to N(CH2)4CN>+3SCF3.Both I(CH2)4CN and CF3SO3(CH2)4CN can be converted into the salt NMe>+3SCF3, but this does not form a dinitrilium salt on reaction with acetonitrile.On heating benzophenone oxime with CF3SO3H Beckmann rearrangement products are obtained, but conversion of +SCF3 into the nitrilium salt NPh>*3SCF3 ocuurs in only low yield even after 8 h at 130 deg C under high vacuum.The nitrilium salts with R = Ph, Me, Pri, and PhCH2 undergo rapid exothermic reaction with phenol, thiophenol, alcohols, and thiols to give the corresponding imidate and thioimidate salts in high yields. 4,4-Dimethy-2-phenyl-1,3-oxazoline is obtained in 74percent yield on heating NMe>+*3SCF3 with H2NCMe2CH2OH, and both this and 2,4,4-trimethyloxazoline react with MeO3SCF3 to give almoust quantitative yields of the corresponding N-methyloxazolinium salts, which can be reduced to the oxazolidines with NaBH4.N-Methyloxazolinium salts have also been obtained from the reactions of nitrilium salts (R = Ph or Me) with ethylene oxide.
