NEOCLEORDANE DITERPENOIDS AND THEIR ARTIFACTS FROM TEUCRIUM-OLIVARIANUM

The aerial parts of Teucrium oliverianum yielded five new neocleordane diterpenoids (teucrolins A [4], B [5], C [6], D [6], and E [8]), three neocleordane diterpene artifacts (12-O-methylteucrolivin A [9], 12-O-methylteucrolin A[10], and 12-O-ethylteucrolin A [11]), and the three known diterpenoids teucrolivins A [1], B [2], and C [3]. In addition, four other known compounds were isolated: the sterol 24(S)-stigmasta-5,22,25-trien-3beta-ol, the iridoid 8-O-acetylharpagide, and the flavones eupatorin and cirsiliol. The structural assignments of all new diterpenoids and their artifacts were based on 1D and 2D nmr spectral data, chemical derivatization, and X-ray crystallographic analysis of 10; the latter established the relative stereochemistry and the presence of the rare axial substitution at C-3 in 10 and related compounds.