DP4-Assisted Structure Elucidation of Isodemethylchodatin, a New Norlichexanthone Derivative Meager in H-Atoms, from the Lichen Parmotrema tsavoense

Thuc-Huy Duong (1) , Mehdi A Beniddir (2) , Joël Boustie (3) , Kim-Phi-Phung Nguyen (4) , Warinthorn Chavasiri (5) , Guillaume Bernadat (6) , Pierre Le Pogam (2)

1 Ton Duc Thang University [Hô-Chi-Minh-City]
2 MBCIS - Molécules bioactives, conception, isolement et synthèse
3 ISCR - Institut des Sciences Chimiques de Rennes
4 HCMUS - Ho Chi Minh City University of Science
5 Chulalongkorn University [Bangkok]
6 INSU - CNRS - Institut national des sciences de l'Univers

A phytochemical investigation of the foliose lichen (Krog and Swinscow) Krog and Swinscow (Parmeliaceae) resulted in the isolation of a new trichlorinated xanthone, isodemethylchodatin. The structure elucidation of this new norlichexanthone derivative proved tricky owing to proton deficiency, and to the lack of NMR data of closely related analogues. The structure of this compound was determined based on an integrated interpretation of C-NMR chemical shifts, MS spectra, and DP4-based computational chemistry was also performed to provide an independent and unambiguous validation of the determined structure. Isodemethylchodatin represents the first chlorinated lichexanthone/norlichexanthone derivative bearing a methoxy group at C-5.

Keywords: norlichexanthone; xanthone; lichen; Parmotrema; DFT-NMR

Domains: Chemical Sciences; Medicinal Chemistry

Thuc-Huy Duong, Mehdi A Beniddir, Joël Boustie, Kim-Phi-Phung Nguyen, Warinthorn Chavasiri, et al.. DP4-Assisted Structure Elucidation of Isodemethylchodatin, a New Norlichexanthone Derivative Meager in H-Atoms, from the Lichen Parmotrema tsavoense. Molecules, 2019, 24 (8), pp.1527. ⟨10.3390/molecules24081527⟩. ⟨hal-02120744⟩