ABSTRACT
A route for the degradation of the side chain of ent-labdane derivatives has been devised, giving the useful synthon 2beta,12-dihydroxy-13,14,15,16,17-pentanor-ent-labdane-8-one (8). The use of this compound in the preparation of terpenylquinone derivatives shall be reported elsewhere. In addition we have synthesized the compound 2beta,12-diacetoxy-8beta,17-epoxy-13,14,15,16-tetranor-ent-labdane (10), which upon catalytic epoxide ring opening in alkaline or acid media gave rise in all cases to the formation of tricyclicc ompounds.
Subject(s)
Diterpenes/chemistry , Diterpenes/metabolism , Magnetic Resonance Spectroscopy , Models, Molecular , Oxidation-ReductionABSTRACT
Four 9-epi-ent-labdanes were isolated from the aerial parts of Calceolaria inamoena. Their structures, 2beta-hydroxy-9-epi-ent-labda8(17)-13(E)dien-15-oic acid, 2beta-hydroxy-9-epi-ent-labda8(17)-13(Z)dien-15-oic acid, 2beta-hydroxy-9-epi-ent-labda8(17)-13(E)dien-15-al and 2beta-hydroxy-9-epi-ent-labda-8(17)-13(Z)dien-15-al, were established by spectroscopic methods including by analysis of 2 dimensional heteronuclear correlation experiments 1H/13C (normal and long range), and NOE and gs-sel-1D-NOESY and TOCSY of their methyl ester or acetyl derivatives.
