Neoclerodane diterpenoids from Teucrium montbretii subsp. Libanoticum and their absolute configuration

From the aerial parts of Teucrium montbretii subsp. libanoticum 10 neoclerodane diterpenoids were isolated. Three of them are new [3b-hydroxyteubutilin A (I), 12-epi-montanin G (II), 20-epi-3,20-di-O-deacetylteupyreinidin (III)], whereas the other seven, namely, 6-ketoteuscordin, teuscordinon, 6b-hydroxyteuscordin, montanin D, 3,20-di-O-deacetylteupyreinidin, montanin G, and 3-O-deacetylteugracilin A, are previously known structures. The structures of I-III were detd. by spectral and chem. methods.