Structure of lophopterol

Summary When suberosin is allowed to stand in chloroform at room temperature with access of atmospheric oxygen, photooxidation takes place with the formation of at least three substances: (II), C₁₅H₁₆O₄, mp 172–174°C; (III), C₁₅H₁₆O₅, mp 184–185°C; and (IV).It has been established by NMR and mass spectroscopy and also by their chemical properties, that (II) is 6-(3-hydroxyisopent-2-en-1-yl)-7-methoxycoumarin (trans-suberenol) and (III) is 6-(1,2-epoxy-3-hydroxyisopentyl)-7-methoxycoumarin (lophopterol). The nature of (IV) has not yet been determined.It has been shown experimentally that no such oxidation takes place with an isomer of (I) — osthole (IX). A scheme for the biogenesis of coumarins in the organism of the plant investigated has been put forward.Leningrad Sanitary-Hygienic Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 131–133, March–April, 1975.