ABSTRACT

India is a rich country in terms of biodiversity & natural products, but very little work is carried out on stereochemical & spectroscopic studies of natural products. Isomers of natural products are found to be active, but the detection of stereochemical/spectral data is not effectively achieved. There is tremendous scope for spectroscopic methods in the determination of stereochemistry of some novel natural products particularly on J based approach (coupling constant values) which reveals about configuration, conformation and reactivity. Coupling varies with the angle between bonds, ring size affects coupling, electronegative atom reduces coupling, ? system increases geminal coupling, proton attached to same carbon can be different (diastereotopic) and can couple to one another, and we have the Nuclear Overhauser Effect. With these connections stereochemistry of some novel natural products is explained by using coupling constant values (spectroscopic methods). The present review is aimed at highlighting the significance and need of stereochemical & spectral studies of natural products which can be explored as promising drugs of the future.