silica-bonded n-propyldiethylenetriamine sulfamic acid (sbpdsa) was found as an efficient solid acid for the synthesis of coumarins. coumarin derivatives were obtained via the pechmann condensation reaction of phenols and β-keto-esters at 80 oc under solvent-free conditions. also, biscoumarins were obtained via the condensation of aldehydes and 4-hydroxycoumarin in water at reflux conditions. t...

Absract: Rotational dynamics of two structurally similar coumarins; coumarin 7 and coumarin 30 has been studied using a steady state fluorescence depolarization technique and time correlated single photon counting method as a function of temperature in ethanol and n-decane solvents. Experimentally measured reorientation times of these coumarins are identical in a given solvents at a particular ...

UNLABELLED BACKGROUND Coumarin derivatives exhibit a wide range of biological properties including promising antioxidant activity. Furthermore, microwave-assisted organic synthesis has delivered rapid routes to N- and O-containing heterocycles, including coumarins and thiazoles. Combining these features, the use of microwave-assisted processes will provide rapid access to a targeted coumarin...

Coumarins belong to a diverse group of naturally occurring non-nutrient phytochemicals known as benzo-alpha-pyrones. In this study, esculetin, a 6,7-dihydroxy derivative of coumarin with pleiotropic biological activities, was found to have no significant cytotoxic effect on normal murine macrophages, but it could increase the in vivo migration of the thioglycollate-elicited macrophages in a dos...

A high-speed counter-current chromatography (HSCCC) method for separation and purification of coumarins from Cnidium monnieri (L.) Cusson was developed by using stepwise elution with a pair of two-phase solvent system composed of light petroleum-ethyl acetate-methanol-water at volume ratios of 5:5:5:5, 5:5:6:4 and 5:5:6.5:3.5. Five kinds of coumarins were obtained and yielded 7.6 mg of xanthoto...

The ionic liquid 1,3-dimethylimidazolium methyl sulfate, [MMIm][MSO₄], together with a small amount of water (the amount taken up by the ionic liquid upon exposure to air), acts efficiently as both solvent and catalyst of the Knoevenagel condensation reactions of malononitrile with 4-substituted benzaldehydes, without the need for any other solvent or promoter, affording yields of 92%-99% withi...