Determination of the absolute configuration of the novel anti-trypanosomal iridoid molucidin isolated from Morinda lucida by X-ray analysis. Issue 52 (30th December 2015)

• Record Type: Journal Article
• Authors: Karasawa, Satoru; Yoza, Kenji; Tung, Nguyen Huu; Uto, Takuhiro; Morinaga, Osamu; Suzuki, Mitsuko; Kwofie, Kofi D.; Amoa-Bosompem, Michael; Boakye, Daniel A.; Ayi, Irene; Adegle, Richard; Sakyiamah, Maxwell; Ayertey, Frederick; Aboagye, Frederic; Appiah, Alfred A.; Owusu, Kofi B.-A.; Tuffour, Isaac; Atchoglo, Philip; Frempong, Kwadwo K.; Anyan, William K.; Appiah-Opong, Regina; Nyarko, Alexander K.; Yamashita, Taizo; Yamaguchi, Yasuchika; Edoh, Dominic; Koram, Kwadwo; Yamaoka, Shoji; Ohta, Nobuo; Shoyama, Yukihiro
• Is Part Of: Tetrahedron letters. Volume 56:Issue 52(2015)
• Page Start: 7158
• Page End: 7160
• Publication Date: 2015-12-30
• Subjects: Morinda lucida -- Rubiaceae -- Molucidin -- Anti-trypanosomal activity -- X-ray analysis -- Absolute configuration; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2015.11.031
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Abstract: The strong anti-trypanosomal active compound, molucidin, contains a spirolactone tetracyclic iridoid skeleton and is isolated from Morinda lucida as an enantiomer of oruwacin, which is isolated from the same plant. To confirm the absolute configuration of molucidin, we prepared single crystals of molucidin for X-ray analysis. The absolute configuration of the afforded single crystal was determined by X-ray crystallography using a Cu radiation source. X-ray diffraction data were collected at 93 K in the 2 θ range 7.468–134.99° and analyzed using the SHELXL-2014 program. The corresponding chiral quaternary carbon atoms in molucidin were unambiguously determined as 1 R, 5 S, 8 S, 9 S, and 10 S . Notably, both enantiomers of a single molecule, molucidin and oruwacin, with a rigid structure have been isolated from the same plant species. The biosynthetic pathway for the formation of molucidin is also discussed on the basis of the absolute configuration. Our results for the first time support for structural elucidation of tetracyclic iridoids using X-ray analysis.