ABSOLUTE CONFIGURATIONS OF PITTOSPORATOBIRASIDE A AND B FROM PITTOSPORUM TOBIRA

Article abstract of DOI:10.1016/0031-9422(91)83487-6

The absolute configuration at C-12 of pittosporatobiraside A and B isolated from the leaves of Pittosporum tobira was determined to be S on the basis of the exciton chirality of their dibenzoate derivative.The structures of the two glycosides were thus established to be (1S,9S,10S,11S,12S,14R,16R)-12-<(Z)-2-methyl-1-oxo-2-butenyl>-6,14-dimethyl-2-methylene-9-(1-methylethyl)-15,17-dioxatricyclo<8.7.0.0^11,16>heptadec-5-en-13-one and (1S,9S,10S,11S,12S,14R,16R)-12-(3-methyl-1-oxo-2-butenyl)-6,14-dimethyl-2-methylene-9-(1-methylethyl)-15,17-dioxatricyclo<8.7.0.0^11,16>heptadec-5-en-13-one, respectively.Key Word Index - Pittosporum tobira; Pittosporaceae; leaves; pittosporatobiraside A and B; germacrane-type sesquiterpene; glycosides; absolute configuration.