title: New phenanthrene derivatives from maxillaria densa(1)
abstract: Two new phenanthrene derivatives, 2,5-dihydroxy-3, 4-dimethoxyphenanthrene (1) and 9,10-dihydro-2,5-dihydroxy-3, 4-dimethoxyphenanthrene (2), were isolated from an extract prepared from the whole plant of the orchid Maxillaria densa with spasmolytic activity. In addition, four known compounds, namely 2,7-dihydroxy-3, 4-dimethoxyphenanthrene, 9,10-dihydro-2,7-dihydroxy-3, 4-dimethoxyphenanthrene (3), 2,5-dihydroxy-3,4, 9-trimethoxyphe-nanthrene, and 2,7-dihydroxy-3,4, 9-trimethoxyphenanthrene, were obtained. The structures of the isolated compounds were elucidated by spectroscopic methods. In the case of phenanthrene derivatives 1 and 3, the structures were unambiguously assigned by X-ray analysis.
authors.affiliation: Departamento de Farmacia, Facultad de Quimica and Instituto de Quimica, Universidad Nacional Autonoma de Mexico, Coyoacan 04510, Mexico D.F., Mexico.
authors.initials: S
authors.lastname: Estrada
authors.initials: RA
authors.lastname: Toscano
authors.initials: R
authors.lastname: Mata