Evaluation of the Benefit and Informing Capability of 2D NMR Experiments for Computer-Assisted Structure Elucidation
Dimitris Argyropoulos, NMR Business Manager, ACD/Labs
Authors: Dimitris Argyropoulos and Mikhail Elyashberg
Advanced Chemistry Development (ACD/Labs) Inc., Toronto, Canada
The most significant improvement in the 50-year history of Computer-Assisted Structure Elucidation (CASE) [1,2] came after the introduction of routine 2D NMR experiments in the 1990s. The increased information content of these experiments allowed substantially more complex problems to be addressed than ever before. With the simultaneous advances in computing, CASE has now become an established tool for resolving the unprecedented structures of natural products . Today, further advancements in CASE involve the evaluation of advanced NMR experiments and the determination of the minimum set of experiments required to solve a structure. Although these answers vary with problem complexity, we begin to address both questions through a few examples in this poster.
In the first example, we use the very simple molecule 2-Ethylindanone to examine the benefits of basic NMR experiments and their effect on calculation time. Then, we examine the benefits and potential consequences of using modern experiments like LR-HSQMBC, in addition to the traditional HSQC and HMBC using the complex natural product Spirodactylone . The influence of manually adjusting atom properties (e.g. hybridization and connection to heteroatoms) is also examined using this molecule. Finally, a xanthone-class natural product [5-6] is used to consider the inter-relation between HMBC and INADEQUATE in CASE.
Details of spectra, calculations, and a comparison of the achieved improvements in performance will be shown.
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