An efficient ZrCl4 catalyzed one-pot solvent free protocol for the synthesis of 4-substituted coumarins

Preparation, characterization and use of 1,3-disulfonic acid imidazolium hydrogen sulfate as an efficient, halogen-free and reusable ionic liquid catalyst for the trimethylsilyl protection of hydroxyl groups and deprotection of the obtained trimethylsilanes

“…Obviously these advantages make our system as a better choice. It is important to note that, although ZrCl 4 is a useful promoter for the silylation of triphenyl methanol (Table 4, entry 5), its applicability is influenced by its moisture sensitivity and decomposition accompanied by liberation of corrosive HCl fumes on storing [66].…”

Applications of Zirconium (IV) Compounds in Organic Synthesis

“…The classical Pechmann synthesis of these compounds involves the condensation of phenols with -ketonic esters in the presence of variety of acidic condensing agents. ZrOCl 2 ·8H 2 O [98] and ZrCl 4 [99][100][101] have been found to be efficient catalyst for the synthesis of coumarins under the Pechmann reaction conditions (Scheme 45). The electron donating group on phenol promoted the reaction while the electron withdrawing group inhibited the reaction.…”

Magnetic nanoparticles functionalized ethane sulfonic acid (MNESA): as an efficient catalyst in the synthesis of coumarin derivatives using Pechmann condensation under mild condition

“…This reaction has been studied with different homogeneous, heterogeneous and Lewis acid catalysts [16,[40][41][42][43][44][45][46][47][48][49][50][51]. Although these methods are suitable for this process, they often suffer from one or more deficiencies such as low yield, prolonged reaction time, tedious work-up processes, expensive reagents and hazardous reaction conditions [52][53][54].…”