silica gel has been used for synthesis of biscoumarin derivatives starting from 4-hydroxycoumarin and aryl aldehydes. the reaction conditions are completely in agreement with green chemistry principles including sing water as media and a recyclable and safe catalyst. this method is also simple and inexpensive and leads to high yield of products in short reaction times.

Density functional calculations with Becke’s three parameter hybrid method using the correlation functional of Lee, Yang and Parr (B3LYP) were carried out for 3,30-benzylidenebis(4-hydroxycoumarin) (phenyldicoumarol, PhDC), 3,30-methylenebis(4-hydroxycoumarin) (dicoumarol, DC) and the parent compound, 4-hydroxycoumarin (4-HC). Different basis sets were tested in the course of the calculations: ...

Coumarin derivatives possessing diverse biological activities play important roles as versatile building blocks for the synthesis of natural products and biologically active compounds. In particular, 4-hydroxycoumarin derivatives, such as 4-hydroxycoumarin and 4-hydroxythiocoumarin, have been used as useful intermediates for the synthesis of anticoagulants, herbicides, and anticancer agents. Re...

Activity-guided fractionation of twigs of Pistacia chinensis resulted in the isolation and characterization of two novel ingredients as potent estrogen agonists. On the basis of spectral analysis and comparison with a related compound their structures were elucidated as 3,3''-dimers of 4-aryldihydrocoumarins (3,4-dihydro-4-(4'-hydroxyphenyl)-7-hydroxycoumarin) differing only in the stereochemic...

7-Hydroxycoumarin (umbelliferone, 1), the main metabolite of coumarin, has been reported to produce potent antinociceptive effects in animal models of pain. However, the biochemical events involved in antinociception mediated by 1 are currently not well understood. In the present study, the mechanisms by which 1 exerts its pharmacological actions were investigated. Acute pretreatment of mice wi...

The effects of some coumarins (coumarin, 7-hydroxycoumarin, scopoletin and esculetin) were investigated on pumpkin (Cucurbita maxima Duch.) seedlings and on pumpkin glutathione S-transferases (GSTs). Coumarin and esculetin suppressed the growth of seedlings, especially the elongation of roots as well as hypocotyls. Among the compounds tested, only esculetin inhibited the activity of a particula...