Highly efficient and recyclable phosphoric acid functionalized zirconia encapsulated-Fe3O4 nanoparticles: clean synthesis of 1,4-dihydropyridine and 1-amidoalkyl-2-naphthol derivatives

Fe3O4@L‐arginine magnetic nanoparticles: A novel and magnetically retrievable catalyst for the synthesis of 1′3‐diaryl‐2N‐azaphenalene

“…Then, 2 mg of L ‐arginine and 30 mL of ammonia solution were added to male 25 % solution until the pH of the solution reaches 11. The above combination was kept under reflux conditions for 6 hr at 100 ° C. The Fe 3 O 4 @ L ‐arginine nanocatalyst was separated from the aqueous solution by an external magnet and eventually washed and dried for 24 hr (Scheme ) …”

“…The significant merits of the catalyst were related to its facile recyclability using an external magnetic field, reusability for at least five reaction cycles, excellent activity, high stability, mild reaction conditions, and high isolated yields of the products …”

Highly dispersible Fe3O4‐Ag@OPO(OH)2 nanocomposites as a novel eco‐friendly magnetic retrievable catalyst for the reduction of p‐nitrophenol

“…The Fe 3 O 4 ‐ZrO 2 ‐OPO(OH) 2 nanocatalyst showed extraordinary activities in the multicomponent reactions during the simple and efficient preparation of dihydro‐pyridines as well as 1‐amido alkyl‐2‐naphthols. [ 49 ] Zakeri et al offered a simple procedure for the preparation of highly dispersible phosphoric acid‐functionalized GO‐OP(OH) 2 . The prepared nanocatalyst (GO‐OPO(OH) 2 ) exhibited catalytic performance toward the multicomponent synthesis of pyrano‐pyrazole, with 80–90% yield within 15 min in the aqueous solution.…”

Facile One-Pot Synthesis of Amidoalkyl Naphthols and Benzopyrans Using Magnetic Nanoparticle-Supported Acidic Ionic Liquid as a Highly Efficient and Reusable Catalyst

“…These 1-amidoalkyl-2-naphthol and tetrahydrobenzo [b]pyran derivatives are of particular value because of their promising biological and pharmacological activities [7][8][9]. The preparation of amidoalkyl naphthols has been carried out by a three-component condensation of aldehydes, 2-naphthols and amides using different catalysts such as Ba 3 (PO 4 ) 2 [10], Nano Al 2 O 3 [11], supported heteropolyacid [12,13], magnetic sulfonic or phosphoric acid [14][15][16], β-CD-BSA [17], [C 6 [18], MWCNT@Co-complex [19], sulfonated polynapthalene [20] and grapheme oxide [21] in the last five years.Despite undeniable advantages of these methods, a great part of themsuffer from one or more shortcomings such as high reaction temperature, prolonged reaction time, low yield and difficult catalyst separation and recovery. In addition, most of them are limited to only aromatic aldehydes and the reactions with aliphatic aldehydes were reported to suffer from low yields and harsh reaction conditions.…”