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

Table 5

The recycling experiment ASA in Pechmann condensation of resorcinol (1 mmol) with ethyl acetoacetate (1 mmol) using ASA (0.02 g) at 100°C in solvent-free conditions.

Run	1	2	3
Yiled (%)	98	96	90