Silica supported perchloric acid (HClO4-SiO2): A highly efficient and reusable catalyst for geminal diacylation of aldehydes under solvent-free conditions

Multi-Layer Functionalized Poly(Ionic Liquid) Coated Magnetic Nanoparticles: Highly Recoverable and Magnetically Separable Brønsted Acid Catalyst

“…38 Generally, they are synthesized from acetic anhydride and aldehydes using strong protonic acids, 39 Lewis acids, 40 and supported reagents. 41 ■ RESULTS AND DISCUSSION Synthesis of Modified Magnetic Nanoparticles. The magnetic (Fe 3 O 4 ) nanoparticle was synthesized by the coprecipitation technique based on a reported method.…”

Preparation of Silica‐bonded Propyl‐diethylene‐triamine‐N‐sulfamic Acid as a Recyclable Catalyst for Chemoselective Synthesis of 1,1‐Diacetates

“…All the products were characterized by comparison of their IR, 1 H NMR and 13 C NMR spectroscopic data and their melting points with the reported values. [16][17][18][19][20][21][22][23][24][25][26][27][28][29] Chloropropyl silica was prepared by a known procedure as previously reported. 37…”

“…8,9 Generally, they are synthesized from acetic anhydride and aldehydes using strong protonic acids, 6,10,11 Lewis acids, 2,12-14 heterogeneous catalysts, 15,16 and supported reagents. 17,18 Other catalysts, such as iodine, 19 copper p-toluene-sulfonate/HOAc, 20 and 1,3-dibromo-5,5-dimethylhydantoin, 21 have also been used for this transformation, but these procedures are often accompanied by longer reaction times, poor product yields, stringent conditions, good catalyst loading; require the use of toxic solvents; and so on. More recently, supported catalysts, 22,23 silica-bonded S-sulfonic acid, 24 poly(N,N'dibromo-N-ethylbenzene-1,3-disulfonamide), 25 ferrous methansulfonate, 26 cobalt(II) bromide, 27 and SO 3 Hfunctionalized ionic liquids, 28 were reported for the synthesis of 1,1-diacetates.…”

Silica‐supported ICl as a novel heterogeneous system for the rapid oxidation of urazoles to triazolinediones

“…Recently, silica-supported reagents have received considerable attention because of higher activity due to the larger surface area, high mechanical and thermal stabilities, easy handling, low toxicity, noncorrosiveity, easy separation, and work-up [10]. On the other hand, heterogeneous processes have been well studied recently for its prospective applications in organic synthesis.…”