Solving challenging bioorganic problems by exciton coupled CD

Abstract- Determination of molecular chirality is becoming increasingly important due to the sophistication in mode of action studies of biological reactions and the importance of chiral drugs. The exciton coupled CD, based on through space coupling, is a versatile microscale method with superb sensitivity that can be applied to a variety of problems including biopolymers and clusters in lipids. Applications of the exciton coupled CD method to the following problems exemplify its versatility. 1. Quaternary ammonium salts as chromophores for exciton-coupled CD.1' Exciton coupled circular dichroism is a nonempirical submicrogram scale method for determining absolute configurations and conformations of organic molecules in solution based on the interactions of chromophores which are preexisting in the substrate and/or introduced through derivatizations such as 0- or N-acylation.213 However, the method could not be applied to one major group, i.e., tertiary amines which comprise numerous natural products, particularly alkaloids, and synthetic drugs that exhibit conspicuous biological activities. We have succeeded i