Ball milling for the quantitative and specific solvent-free Knoevenagel condensation + Michael addition cascade in the synthesis of various 2-amino-4-aryl-3-cyano-4H-chromenes without heating

Abstract

Various 2-amino-4-aryl-3-cyano-4H-chromenes have been quantitatively prepared by dry ball milling in the presence of catalytic Na2CO3. The orientation specificities are discussed; existing misattributions are pointed out and clarified by NMR.

Synthesis and characterization of sodium polyaspartate‐functionalized silica‐coated magnetite nanoparticles: A heterogeneous, reusable and magnetically separable catalyst for the solvent‐free synthesis of 2‐amino‐4H‐chromene derivatives

“…[cmmim]Br (10 mol%) Solvent-free, 110°C 5 min 90 [37] 12 Na 2 CO 3 (10 mol%) Ball milling, R.T. 25 min 99 [35] 13 Nano CP (0.01 g) g H 2 O, reflux 15 min 95 [55] 14…”

Meglumine Promoted Strategy: Environmentally Benign Protocol towards the Synthesis of Polysubstituted 2‐Aminopyrroles in Aqueous Condition

“…Recently, multi‐component reactions (MCRs) has grab considerable attention because it's efficient access to highly complex final products in a single step ,. MCRs have proven to be more powerful and superior to classical multistep approaches because it can shorten the reaction time, improve the atom economy, reduce the separation steps, operational simplicity as well as give usual excellent productivity . Moreover, MCRs are environmentally friendly and have simpler and cheaper purification technique .…”

Design, Synthesis and Molecular Docking Studies of Novel Triazole‐Chromene Conjugates as Antitubercular, Antioxidant and Antifungal Agents

“…Owing to this enormous biological importance of chromene scaffold in medicinal chemistry, a number of synthetic protocols have been developed for the synthesis of 4 H ‐chromene which includes one‐pot three‐component synthesis by using K 2 CO 3 , trifluoroethanol, Na 2 CO 3 , nano polypropylenimine dendrimer (DAB‐PPI−G1), MgO, TPOP‐2, POPI under ball milling, hydrotalcite (HT), CuO‐CeO 2 nano composite, Na 2 CO 3 under ball milling, piperidine under MWI, Fe 3 O 4 ‐chitosan nanoparticles, amino‐silane modified Fe 3 O 4 nanoparticles and glycine . Despite a lot of methods are presently available with its own merits, most of these methods possess one or more of the limitations such as use of hazardous catalyst and solvent along with low yield, longer reaction time, tedious work up procedure and drastic reaction conditions, etc.…”