Abietane diterpenes with antibiotic activity from the flowers of Salviacanariensis. Reaction of galdosol with diazomethane

Abstract

The new diterpenes canariquinone (9), rosmaquinone (10), and 11-acetoxycarnosic acid (6), together with the already known 7-ethoxyrosmanol (1), 7-methoxyrosmanol (2), and rosmanol (3), were isolated from the flowers of Salviacanariensis. The structure of the new substances was established by a combination of chemical and spectroscopic means. Reaction of galdosol (4), isolated from the aerial part of the same plant, with diazomethane, unexpectedly gave the new homoditerpenes 15 and 16, the structures of which were determined by spectroscopic methods. A mechanism accounting for the formation of these substances is suggested. Keywords: abietane diterpenes, Salvia, Labiatae, antibiotic activity, galdosol reactivity.