Structure Revision of Formyl Phloroglucinol Meroterpenoids: A Unified Approach Using NMR Fingerprinting and DFT NMR and ECD Analyses.

ABSTRACT: NMR fingerprints are valuable tools for analyzing complex natural product mixtures and identifying incorrectly assigned structures in the literature. Our diagnostic NMR fingerprints for formyl phloroglucinol meroterpenoids revealed discrepancies in the structures reported for eucalyprobusal C (1a) and eucalypcamal K (2a). NMR fingerprinting PCA analyses identified 1a as an oxepine-diformyl phloroglucinol and 2a as an oxepine 3-acyl-1-formyl phloroglucinol, contrary to their initial assignments as pyrano-diformyl and pyrano 3-acyl-1-formyl phloroglucinols, respectively. Extensive reinterpretation of their reported one- and two-dimensional NMR data, coupled with GIAO DFT-calculated ¹H and ¹³C NMR chemical shift and DP4+ analyses, supported th

SUBMITTER: Holland DC 

PROVIDER: S-EPMC10856187 | biostudies-literature | 2024 Jan

REPOSITORIES: biostudies-literature