ABSTRACT
Optical rotatory dispersion (ORD) and circular dichroism (CD) are applicable to the analysis of naturally occurring pesticides only in special cases. This chapter discusses ORD and CD, instrumentation, and examples of their applications to natural pesticides. ORD and CD have been used to obtain information about configuration and conformation of natural insecticides, pheromones, plant and insect hormones, and metabolites of synthetic pesticides. Absolute configuration can be assigned for compounds of unknown configuration, in cases for which empirical rules do not exist, by comparison of ORD or CD curves of the unknown with curves of similar compounds of known configurations. There are a number of other natural insecticides which are optically active and can be studied by ORD and CD. Absolute stereochemistry can be assigned by proper use of ORD or CD spectra along with other spectroscopic data and chemical intuition and sometimes judicious use of chemical reactions.
