New NOAH modules for structure elucidation at natural isotopic abundance.

We introduce several new NOAH modules designed for NMR supersequences that allow structure elucidation of small organic molecules from a single measurement. We show that double isotope filters (ZZ-filters) increase the flexibility of module permutation within the NMR supersequences, optimising combinations exploiting ¹⁵ N and ¹³ C nuclides. The time-shared 2BOB module combined with the ZZ-HMBC module (yielding NOAH-2 BO) provides an example of extending the NMR supersequences with parallel experiments (here 2BOB) that are incompatible with sequential implementation. Finally, the PANSY-COSY module combined with the HSQC sequence (yielding NOAH-2 SC ² ) provides an example of incorporating multiple receiver experiments into NMR supersequences opening new avenues for designing information rich NMR experiments. The new NOAH supersequences were utilized in computer assisted structure elucidation (CASE) study accomplished using the CMCse software.
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