Easy Access to Coumarin Derivatives Using Alumina Sulfuric Acid as an Efficient and Reusable Catalyst under Solvent-Free Conditions

Table 2

Optimization of the amount of ASA in Pechmann condensation of resorcinol (1 mmol) with ethyl acetoacetate (1 mmol) in solvent-free conditions at 110°C.

Entry	ASA (g)	Yield (%)
1	0.01	70
2	0.02	90
3	0.03	85
4	0.04	85