Characterization and crystal structure of 2R-(−)-6-hydroxytremetone from Xenophyllum poposum (Phil.) V.A. Funk

Abstract

2R-(−)-6-Hydroxytremetone (C13H14O3) is a bioactive metabolite isolated from Xenophyllum poposum (Phil.) V.A. Funk. (ex. Werneria poposa Phil.), a member of the Asteraceae. Various pharmacological properties attributed by popular medicine to benzofurane derivatives prompted their physical and chemical characterization. The obtained substance was characterized by melting point, optic rotation, ultraviolet spectrum, 1HRMN, 13CRMN, infrared spectroscopy, and thermo-analytical techniques. The molecular structure of 2R-(−)-6-hydroxytremetone was determined by single crystal X-rays diffraction methods. The substance crystallizes in the monoclinic space group P2 1 with a = 8.767(2) Å, b = 5.423(1) Å, c = 24.301(4) Å, β = 90.52(2)°, and two independent but very similar molecules of the same handedness per asymmetric unit (Z = 4). Both molecules have the phenyl ring and its attached oxydryl and methyl ketone groups nearly co-planar to one another and are stabilized by a strong OH ··· Oketone intra-molecular bond (Ohydroxyl ··· Oketone distances of 2.529 and 2.536 Å; O–H ··· Oketone angles of 146.4 and 143.9°, respectively).