Structure Elucidation

Natural Products

The structural diversity of natural products is vast and presents a significant challenge in structure elucidation.  To further compound the challenge, natural products are also often isolated in very small quantities.
 
The combination of highly sensitive probe technology, such as CryoProbes and MicroProbes, together with sophisticated instrumentation capable of performing the newest experiments with high precision and low artifacts, is essential for rapidly overcoming these structural challenges.
 

Structure elucidation of natural products is problematic due to the limited sample quantity and often complex structures. Typically, the structure elucidation of small quantities of a molecule relies on the typical 1H detected NMR experiments such COSY, TOCSY, NOESY, 1H,13C-HMQC and 1H,13C-HMBC experiments. Natural abundance 15N measurements have always been restricted due to the low abundance of naturally occurring 15N in samples. Labeling is costly and time consuming and is, therefore, only undertaken if absolutely required.

However, CryoProbes, by virtue of their dramatically improved sensitivity, make it possible to obtain a complete NMR dataset ebnabling the complete structure elucidation of these challenging molecules.
more on CryoProbes
 

 The following data compares the results for a 25 minute HMBC (1H,13C) Gradient Sensitivity Enhanced experiment run in a CryoProbe using an AVANCE 500.
more on AVANCE NMR spectrometers
 
The sample below was a kind gift of Dr. John Leet, from Bristol Meyers Squibb Company.
 

Comparison of CryoProbe and room temperature probe results
CryoProbe
Conventional probe