86774-78-9Relevant articles and documents
The Chemistry of Nitrilium Salts. Part 3. The Importance of Triazinium Salts in Houben-Hoesch Reactions Catalyzed by Trifluoromethanesulphonic Acid
Amer, Muhannad I.,Booth, Brian L.,Noori, Ghazi F. M.,Proenca, M. Fernanda J. R. P.
, p. 1075 - 1082 (2007/10/02)
In the presence of trifluoromethanesulphonic (triflic) acid, isobutyronitrile reacts with anisole, 1,3-dimethoxybenzene, resorcinol, 1,3,5-trimethoxybenzene, and phloroglucinol at room temperature to give acylation products.A study of the reactions of acetonitrile and isobutyronitrile with triflic acid has shown that these modified Houben-Hoesch reactions occur by initial cyclotrimerization of the nitriles to 1,3,5-triazinium triflate salts followed by a slow reaction of the salts with the aromatic substrate.Support for this comes from the isolation of 2-(4-methoxyphenyl)-2,4,6-tri-isopropyl-1,2-dihydro-1,3,5-triazine from the reaction between anisole, triflic acid, and isobutyronitrile.Similar 1,2-dihydro-s-triazines and their salts have been prepared by reaction of trimethyl-s-triazinium triflate with 1,3-(MeO)2C6H4, and tri-isopropyl-s-triazinium triflate with 1,3-(RO)2C6H4 (R = H or Me) and 1,3,5-(MeO)3C6H3; these salts are easily hydrolyzed to the corresponding aromatic ketones.The salt +23SCF3 also reacts with o-phenylenediamine to give 2-methylbenzimidazolinium triflate in 83percent yield.Nitrilium salts NMe>+NMe>+3SCF3 at room temperature.
