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Green Chemistry Approach for Synthesis of Derivatives of Coumarin and Comparative Study by Fluorescence Spectrophotometer

Manisha M. Kodape, Nandkishor D. Gawhale, Digvijay D. Kamble, Suverna A. Dabhade and Nikita V. Awajare

Even though several methods for coumarin synthesis have been reported. While the majority of their earlier syntheses requires reactant material which is expensive, in some methods high amount of energy is required to complete the reaction, some methods produces by products which are hazarded to environment, some methods are not possible in large industrial scale, while some are having low practical yield. One reaction which overcomes all the above things, the well known Pechmann condensation was used for the preparation of 7-hydroxy coumarin followed by O-allylation in polyethylene glycol 400 which is the one step towards green chemistry approach and then Claisen rearrangement afforded the 8-allyl-7-hydroxy-4-methylcoumarin. Fluorescence is very simple and non destructive technique; it is also very sensitive, selective and specific type of technique. As all coumarin molecules are fluorescent and they show different absorption and emission spectra, they are sensitive in different environment so it is interesting to study the effect of different solvents (ethanol, methanol, CCl4,hexane) on the six different derivatives of coumarin. It was found that the intensity of peak will increase from non-polar to polar solvent and wavelength decreases.