Synthesis and fluorescence studies on menthol-coumarin conjugates

摘要

A three-step protocol for synthesis of alcohol containing aliphatic natural products and coumarins has been described. The Blaise reaction of converting the nitrile to beta-keto esters formed key-step in this protocol. The menthol-coumarin conjugates prepared for the first time are subjected to absorption and fluorescence emission studies. The studies reveal that menthol substitution has little influence on the absorption or emission characteristic of the chromophore. However, substitution of C(6)H or C(6)OMe of the coumarin with NEt2 has dramatic influence on both absorption and emission of the conjugate. Solvatochromic studies and analysis of Stoke shift data show that the menthol-coumarin conjugate with C(6)NEt2 stabilizes itself in dipolar push-pull structure in ground and excited states.