NEOCLERODANE DITERPENOIDS FROM SCUTELLARIA-ALPINA

Seven new neo-clerodane derivatives, scutalpins G-M, have been isolated from the acetone extract of the aerial parts of Scutellaria alpina, in addition to the previously known diterpenes scutalpins B and D, and scutecolumnin C. The structures of the new compounds were established by spectroscopic means as (13S)-11 beta,19-diacetoxy-6 alpha-benzoyloxy-4 alpha,18;8 beta,13-diepoxy-neo-clerodan-15,16-olide (scutalpin G), (11S)-11,19-diacetoxy-6 alpha-(2'S)-methylbutyryloxy-4 alpha,18-epoxy-8 beta-hydroxy-neo-clerod-13-en-15,16-olide (scutalpin H), (11S)-11,19-diacetoxy-6 alpha-benzoyloxy-4 alpha,18-epoxy-8 beta-hydroxy-neo-clerod-13-en-15,16-olide (scultalpin I) (11E)-19-acetoxy-6 alpha-benzoyloxy-4 alpha,18-epoxy-8 beta-hydroxy-neo-cleroda-11,13-dien-15,16-olide (scutalpin J), (11E)-19-acetoxy-6 alpha,7 beta-dibenzoyloxy-4 alpha,18-epoxy-8 beta-hydroxy-neo-cleroda-11,13-dien-15,16-olide (scutalpin K), 19-acetoxy-6 alpha,7 beta-dibenzoyloxy-4 alpha,18-epoxy-8 beta-hydroxy-neo-clerod-13-en-15,16-olide *scutalpin L) and (11S,13S,14S,16S)-6 alpha,14,19-triacetoxy-4 alpha,18;11,16;15,16-triepoxy-neo-clerodane (scultalpin M). In the case of the 6 alpha,7 beta-dibenzoate derivatives (scutalpins K and L) their neo-clerodane absolute configuration was established by the CD exciton chirality method.