Efficient Synthesis of Novel Coumarin‐3‐carboxamides (=2‐Oxo‐2 H ‐1‐benzopyran‐3‐carboxamides) Containing Lipophilic Spacers

The novel coumarin‐3‐carboxamides (=2‐oxo‐2 H ‐1‐benzopyran‐3‐carboxamides) 5a – 5g containing lipophilic spacers were synthesized through the Ugi ‐four‐component reaction ( Scheme 1 ). The reactions of aromatic aldehydes 1 , 4,4′‐oxybis[benzenamine] or 4,4′‐methylenebis[benzenamine] as diamine 2 , coumarin‐3‐carboxylic acid (=2‐oxo‐2 H ‐benzopyran‐3‐carboxylic acid; 3 ), and alkyl isocyanides 4 lead to the desired substituted coumarin‐3‐carboxamides 5a – 5g at room temperature with high bond‐forming efficiency. These novel coumarin derivatives exhibit brilliant fluorescence at 544 nm in CHCl 3 .