Configuration and stability of naturally occurring all-cis-tetrahydrofuran lignans from Piper solmsianum

Author(s)

Ramos, Clecio S. ^[1] ; Linnert, Harrald V. ^[2] ; de Moraes, Marcilio M. ^[2] ; do Amaral, Joao H. ^[2] ; Yamaguchi, Lydia F. ^[2] ; Kato, Massuo J. ^[2]

Affiliation

^[1] Rural Fed Univ Pernambuco, Dept Chem, Rua Dom Manoel de Medeiros S-N, BR-52171030 Recife, PE - Brazil

^[2] Univ Sao Paulo, Inst Chem, Av Prof Lineu Prestes 748, BR-05508000 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: RSC ADVANCES; v. 7, n. 74, p. 46932-46937, 2017.
• Web of Science Citations: 2

Abstract

The study of variability of the tetrahydrofuran lignan (-)-grandisin in leaves of Piper solmsianum (Piperaceae) revealed two unknown compounds, that were isolated and determined to be the all-cis tetrahydrofuran lignans 1a {[}rel-(7R,8S,7'S,8'R)-3,4,5,3',4',5'-hexamethoxy-7,7'-epoxylignan] and 1b {[}rel-(7R,8S,7'S,8R')-3',4'-methylenedioxy-3,4,5,5'-tetramethoxy-7,7'-e poxylignan]. Their structures were determined by spectroscopic analysis including 1D and 2D-NMR while their configurations were determined by ECD associated to the density functional theory (DFT) at the B3LYP/6-31G(d,p) level. The hydrogen bonds between methoxy groups in trimethoxyphenyl rings stabilizes the all-trans tetrahydrofuran lignan grandisin by 6.5 kcal mol-1 as compared to the corresponding all-cis isomer of grandisin. The occurrence of all-cis tetrahydrofuran lignans as natural products is a very rare event. (AU)

• FAPESP's process: 14/50316-7 - Dimensions US-Biota São Paulo: Chemically mediated multi-trophic interaction diversity across tropical gradients
• Grantee: Massuo Jorge Kato
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants