Synthesis of 2-Amino-4,6-diarylnicotinonitriles Using Silica-Bound N-Propyl Triethylenetetramine Sulfamic Acid as a Recyclable Solid Acid Catalyst

Sulfamic acid functionalized PVC: a remarkably efficient heterogeneous reusable catalyst for the acid-catalyzed reactions

“…The FT-IR spectrum of PVC-EDA-SO3H shows the absorption band at 3430 cm -1 is attributed to the OH group stretching vibrations of SO3H group, and the peak at about 1110 cm −1 is attributed to the typical vibration bands of SO3 -stretching and the stretching absorption modes of O=S=O of supported SO3H group. Notably, the absorption peak at 1652 cm -1 corresponded to the bending vibration of the N-H bond suffered a slight shift to the direction of low wavenumber after chlorosulfonation of PVC-EDA, these finding confirm that the sulfonic groups are successfully grafted on PVC-EDA by chlorosulfonation reaction [44][45][46][47]. These characteristic vibrations clearly indicate the formation of desired catalytic system.…”

Silica-Bonded N-Propylpiperazine Sodium n-Propionate as Recyclable Basic Catalyst for Synthesis of 3,4-Dihydropyrano[c]chromene Derivatives and Biscoumarins

“…As a continuation of our studies on the design and application of silica-functionalized solid acids or bases as catalysts in organic transformations [27][28][29][30][31][32][33][34], we prepared SBPPSP and studied its catalytic activity in the synthesis of pyrano[c]chromenes and biscoumarins. SBPPSP was prepared by the reaction of 3-silica-bonded N-propylpiperazine and methyl acrylate in methanol, followed by hydrolysis with HCl (0.5 mol/L) and treatment with saturated sodium bicarbonate (Scheme 1).…”

Synthesis of naphthoxazinone derivatives using silica-bonded S-sulfonic acid as catalyst under solvent-free conditions

“…[1][2][3][4][5] Metal colloids, mineral clays and supported reagents on silica gel, alumina and other solid supports are various types of heterogeneous and reusable catalytic systems, which have been designed and used in organic synthesis. Among them, silica-supported catalysts have attracted more attention because they are inexpensive, easy to prepare, and insoluble in most of organic solvents, which make them being recycled from various reactions Along the line of our studies in preparation and application of solid acid and base catalysts in chemical transformations, [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] herein, we report the catalytic activity of some of these catalysts such as, silica-bonded propyl S-sulfonic acid (1), silica-bonded N-propyl sulfamic acid (2), silica-bonded tin chloride (3), silicabonded titanium chloride (4), silica-bonded n-propylimidazolium hydrogen sulfate (5), and silica-bonded n-propyl-methylimidazolium hydrogen sulfate (6)] as heterogeneous solid acid for the synthesis of naphthaoxazines (scheme 1).…”