A green and eco‐friendly synthesis of coumarin substituted‐3‐indoloxanthenes 4(a‐l) has been developed using urea/L‐proline as simple catalyst. Two efficient methods have been described for the synthesis of these 3‐indoloxanthene derivatives. In the first method, Knoevenagel condensation, then Pinner cyclisation followed by 1,4 addition between 4‐hydroxy‐1‐methyl‐2‐oxo‐1,2‐dihydrocoumarin‐3‐carbaldehyde 1(a‐b), with cyclohexane‐1,3‐dione (2) and indole 3(a‐f) using of L‐proline as catalyst was described. In the second method, urea/thiourea catalyzes the same reaction at 100°C for 10 minutes to afford the title compounds 4(a‐l). These two protocols involve eco‐friendly and inexpensive catalysts, give excellent yields of the clean products without the need of column chromatography for their isolation or purification.
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