NEOCLERODANE DITERPENES FROM SALVIA THYMOIDES

The investigation of Salvia thymoides afforded, in addition to known t riterpenes and flavones, four neo-clerodane diterpenoids, 7 alpha-hydr oxy-neo-cleroda-3, 13-dien-18, 19:15, 16-diolide, 7-oxo-neo-cleroda-3, 13-dien-18, 19:15, 16-diolide, 6 alpha, 18, 19-trihydroxy-neo-cleroda -3, 13-dien-15, 16-olide (thymonin) and 6 alpha, 7 beta, 18, 19-tetrah ydroxy-neo-cleroda-3, 15, 16-olide (7 beta-hydroxythymonin). The last two compounds have not been previously described. The structures of th ese compounds were established by chemical and spectroscopic methods. The absolute stereochemistry of thymonin was determined by X-ray analy sis of a bromo derivative. (C) 1997 Elsevier Science Ltd.