Table 4.

Comparison of the catalytic efficiency of Cs/ECH-TMA solid acid (1) with other heterogeneous or homogeneous catalysts for the synthesis of 6a.

Entry	Catalyst	Catalyst loading	Solvent	Temp. oC	Time (min)	Yield (%)	Ref.
1	Co3O4-CNTs	30 mg	EtOH	Reflux	35	97	[114]
2	Vitamin-B1	20 mol%	EtOH	Reflux	60	90	[115]
3	Fe(HSO4)3/SiO2	10 mol%	EtOH	80	60	95	[116]
4	FeF3	5 mol%	EtOH	Reflux	60	92	[117]
5	Al2(SO4)3	10 mol%	EtOH	Reflux	300	87	[118]
6	Cs/ECH-TMA	10 mg	EtOH	Reflux	35	96	This Work