| abstract |
The present invention relates to novel coumarin derivatives of formula (I) wherein: X═O or S; n=zero, 1, 2, 3 or 4; R 5 and R 6 , which can be the same or different, are optionally unsaturated C 1 -C 4 alkyl groups, or together with the nitrogen atom they form a residue of cyclic amines optionally containing other heteroatoms; R 1 ═CH 3 or phenyl; R 2 and R 4, which can be the same or different, are H, OH, allyl, halogen or methyl. |