Perfluorinated Sulfonic acid Resin (Nafion-H) catalysed Ritter reaction of Benzyl Alcohols

Abstract

Perfluorinated sulfonic acid resin (Nafion-H) catalyst found to be effective in promoting the Ritter reaction of benzyl alcohols with nitriles such as acetonitrile, acrylonitrile and benzonitrile to give the corresponding N-benzylamides.

Polyoxometalate–Ionic Liquid-Catalyzed Ritter Reaction for Efficient Synthesis of Amides

“…1 H NMR (700 MHz, CDCl 3 ) δ 7.27 (td, J = 7.9, 5.8 Hz, 1H), 7.07 (d, J = 7.7 Hz, 1H), 7.02 -6.97 (m, 1H), 6.92 (ddd, J = 8.3, 2.5, 1.2 Hz, 1H), 6.37 (s, 1H), 5.10 -5.05 (m, 1H), 1.96 (s, 3H), 1.43 (d, J = 7.0 Hz, 3H). 13…”

“…Among them, 1-phenylethanols with electron-withdrawing groups (2-8) generally gave better results than those with electron-donating groups (9)(10)(11). In addition, bulky substrates, such as 1-(2-naphthyl)ethanol, diphenylmethanol, and 9-fluorenol, were all compatible with the reaction conditions, and afforded the desired products in 74-98% yields (12)(13)(14). Note that, this system can be further extended to other secondary benzylic alcohols.…”

Zn(ClO4)2⋅6H2O‐Catalyzed One‐Pot Synthesis of Amides via Ritter Reaction with Alcohols, Acetic Anhydride and Nitriles

“…The large amount of toxic and corrosive acids used in the reaction limits its application on large scale. Subsequently, a series of novel catalysts including homogeneous and heterogeneous catalysts were developed for replacing the employment of acids . On the other hand, some alternative starting substrates such as acetic esters, halohydrocarbons and ethers were also explored to react with nitriles to form amides.…”

Silica sulfuric acid: a reusable solid catalyst for the synthesis of N-substituted amides via the Ritter reaction

“…Over the years, several variations have been reported for the Ritter reaction to achieve higher yields with better chemoselectivity under milder and environmentally acceptable conditions. These variations include the use of Nafion-H as a solid catalyst, 5,6 Nafion-H along with microwave irradiation, 7 formic acid under reflux, 8 HBF 4 ?Et 2 O, 9 2,4-dinitrobenzenesulfonic acid, 10 HClO 4 -functiona-lized silica-coated nanoparticles, 11 liquid HF, 12 TMSCN/H 2 SO 4 as a reagent for the synthesis of formamides, 13 pentafluorophenyl ammonium triflate (PFPAT), 14 t-BuOAc instead of t-BuOH as a carbocation source, 15 Tf 2 O/ROH as an in situ source of ROTf, 16 metal complexes, 17 Bi(OTf) 3 and other metallic triflates, 12,18,19 ionic liquids, 20 and SiO 2 -Pr-SO 3 H. 21 However, these methods suffer from several disadvantages, such as high cost, poor availability or toxicity of the reagents, and extended reaction times. Additionally the main drawback of most of the existing methods is that the catalysts decompose during the aqueous workup and their recovery is often impossible.…”