Nano-Pd/Chitosan Composite: An Extremely Effective Catalyst to the Synthesis of Pyrazolyl Analogues through Suzuki–Miyaura Cross-Coupling Reactions in an Aqueous Medium

Table 3

Comparison of some advanced heterogeneous Suzuki reactions with the present method.

S. nos.	Catalysts	Reaction conditions	Remarks	References
1	Pd(PCy2)2; XantPhos	NaO^tBu, PhMe PEG-400, 80°C	Carcinogenic solvent used, cocatalyst needed	[31]
2	PdCl2(amphos)2	Na2CO3, water, 80°C	Tedious reaction condition, additive material needed	[32]
3	Pd@rice husk ash	EtOH, K2CO3, 100°C	Ethanol as reaction media, large reaction times are the critical in this protocol	[33]
4	GO-Pd@Ag-AgBr	EtOH, K2CO3, vis. light, 25°C	Very poor yield of the coupling product using aryl chlorides was observed in this protocol	[34]
5	Pd-N-heterocyclic carbene	i-PrOH (4 mL), K2CO3 (1.2 eq)	Multistep preparation of the catalyst, poor yield, and harsh reaction condition	[35]
6	Pd-imi-C@MCM-41/Fe3O4	Na2CO3, PEG-400, 80°C	Involves multistep preparation of catalyst and using PEG-400 as media	[36]
7	GO-NHC-Pd^2+	EtOH, water K2CO3, 80°C	Low yields, reactant are aryl chlorides, and high reaction time	[37]
8	Pd-isatin-boehmite	K2CO3, PEG-400, 80°C	Difficulty in catalyst preparation, and necessity of PEG-400 as media in this protocol	[38]
9	Pd-adenine@boehmite	Na2CO3, water, 80°C	The synthesis of Pd-complex-based catalyst needs multiple steps	[39]
10	Nano-Pd/chitosan composite	Water, 0.02 mol % catalyst, 60°C	High yield and easy purification of products. Water as reaction medium, mild base used with under 60°C. No need for inert atm	[Present work]