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A REVIEW ON BIOLOGICAL ACTIVITY AND SYNTHETIS OF COUMARINS
Authors: G.Nagaraju1 *, Dr.Vijaya Kuchana2

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Coumarin (1,2-Benzopyrone or 2H-1-benzopyran-2-one, or phenylpropanoids, 1) and its derivatives (coumarins)
are widely distributed throughout nature and many exhibit useful and diverse biological activities1,2. Coumarins
occur as secondary metabolites in the seeds, roots and leaves of many plant species, notably in high concentration
in the tonka bean and thus the name comes from a French word, coumarou, for the tonka bean. Their function is far
from clear, although suggestions include plant growth regulations, fungistasis, bacteriostasis and, even, waste
products3
. Some naturally occurring coumarin derivatives include warfarin (2), umbelliferone (7-
hydroxycoumarin, 3), aesculetin (6,7-dihydroxycoumarin, 4), herniarin (7-methoxycoumarin, 5), psoralen (6) and
imperatorin (7). Now the diversity of coumarin derivatives, both natural and synthetic, has grown and are thus
divided into several subclasses. Most reviews classify coumarins according to whether particular compounds are
simple coumarins (e.g. coumarin, 1 and limettin, 8), linear furanocoumarins (e.g. imperatorin, 7 and
isopimpinellin, 9), angular furanocoumarins (e.g. angelicin, 10), linear pyranocoumarins (e.g. xanthyletin, 11) or
angular pyranocoumarins (e.g. seselin, 12)
4
. Murray et al.
5 however, used a biogenetic approach based upon the
number of nuclear oxygen atoms in classifying coumarin-containing compounds. Because of their varied
biological activities, the preparation of coumarin and its derivatives has attracted the attention of organic
chemists. Various synthetic methods have been developed for the synthesis of coumarin. These include use of the
Knoevenagel condensation,Wittig reactions, Perkin reaction and Pechmann reaction.