H2SO4/Silicagel: Highly Efficient Catalyst for the Synthesis of α-Aminonitriles Using Trimethysilyl Cyanide

Synthesis of α‐Amino Nitriles from Carbonyl Compounds, Amines, and Trimethylsilyl Cyanide: Comparison between Catalyst‐Free Conditions and the Presence of Tin Ion‐Exchanged Montmorillonite

“…To overcome these disadvantages, the development of heterogeneous catalyst systems has been focused on. However, in spite of the evident advantages of catalyst recovery and recycling, there have been only a few heterogeneous catalysts reported, these include: montmorillonite KSF, [12] supported heteropolyacids, [13] Fe 3 O 4 nanoparticles, [18] H 2 SO 4 /silica gel, [14] Nafion SAC-13, [19] and PVP-SO 2 complex. [20] Although effective, these systems have drawbacks such as low activity or require large amounts of catalyst.…”

“…[1] ( 1) A broad spectrum of catalysts has been developed to promote the Strecker reactions, such as: metal complexes, [2] Lewis acids, [3][4][5][6][7][8][9][10][11] solid acids, [12][13][14] base catalysts, [15] and organic catalysts, [16] etc. [17] These protocols often require not only the use of valuable reagents, but also involve long reac-as well as aliphatic and aromatic amines, were converted into the desired α-amino nitriles in good to excellent yields with short reaction times under mild conditions.…”

Expeditious and efficient synthesis of Strecker’s α-aminonitriles catalyzed by sulfated polyborate

“…18 Protocols based on TMSCN often require variety of Lewis or Bronsted acid catalyst such as Pr(OTf) 3 , 19 Yb(OTf), 20 Cu(OTf) 2 32 Montmorillonite KSF, 33 polymer-supported Sc(OTf) 3,34 silica-supported heteropoly acids, 35 cellulose sulfuric acid, 36 alumina supported tungstosilicic acid, 37 SBA-15 supported sulfonic acid, 38 sulfamic acid functionalized magnetic Fe 3 O 4 nanoparticles, 39 H 2 SO 4/ Silica gel, 40 silica-bonded S-sulfonic acid, 41 sulphated tungstate, 42 MCM-41 anchored sulfonic acid, 43 nano magnetic sulfated zirconia, 44 sulfamic acid, 45 and xanthan sulfuric acid. 46 However, many of these methods suffer from several shortcomings such as low reactivity, unsatisfactory yields, moisture sensitive nature, longer reaction time, harsh reaction conditions, tedious workup, generation of toxic byproducts, use of expensive, metal-based, corrosive/toxic catalysts or reagent.…”

Graphene Oxide: An Efficient and Recyclable Nano Catalyst for the Synthesis of 2-Substituted Benzimidazoles from Aldehydes and Diamines at Ambient Temperature

“…To the best of our knowledge, only very limited ways about using GO as solid acid catalyst has been investigated and the application of GO served as the lone catalyst in the synthesis of 2substituted benzimidazoles from aldehydes and ophenylene diamines has not been reported before. Ongoing our last studies [49][50][51], we wish to investigate the viability of using GO as the lone catalyst to synthesize 2-substituted benzimidazoles using ary aldehydes and diamines in the presence of graphene oxide as solid acid catalyst at ambient temperature (Scheme 17).…”