138568-11-3Relevant academic research and scientific papers
13C NMR Data for Labdane Diterpenoids
Barrero, Alejandro F.,Altarejos, Joaquin
, p. 299 - 308 (2007/10/02)
The analysis of the 13C NMR spectra of 91 labdane-type compounds, classified into ten different series, is reported. KEY WORDS: 13C NMR, Diterpenes, Labdanes, Substituted trans-decalins, 2D NMR
Oxymercuriation-Demercuriation of the Methyl Esters of Communic Acids. X-Ray Molecular Structure of Methyl (8R,12R)-8,12-Epoxyisopimar-15-en-19-oate
Barrero, Alejandro F.,Sanchez, Juan F.,Altarejos, Joaquin,Perales, Aurea,Torres, Rosario
, p. 2513 - 2523 (2007/10/02)
The oxymercuriation-demercuriation (OM-DM) of methyl (E)-communate with mercury(II) acetate yielded mainly the hydration product of the 14,15-double bond.The isopimarane oxide methyl (8R,12R)-epoxyisopimar-15-en-19-oate, the endoperoxide methyl (8S,12R,13S)-13,17-epidioxy-8,12-epoxylabd-14-en-19-oate and the diorganomercurial bis-(4β-methoxycarbonyl-19-norlabda-8,12E-14-trien-17-yl)mercury were also obtained when NaBH4-NaOH was used as the reducing agent.The organomercurial regenerated methyl (E)-communate on prolonged treatment with NaBH4 in excess.The OM-DM of methyl (E)-communate using Na(Hg) as the reducing agent achieved partial isomerization of the 8(17)-double bond, giving methyl 14-hydroxylabda-8,12E-dien-19-oate and methyl labda-8,12E,14-trien-19-oate; the oxide methyl (8S,12R)-8,12-epoxylabd-13E-en-19-oate, instead of the aforementioned isopimarene oxide, endoperoxide, and diorganomercurial; relatively important amounts of the product of stereoselective 1,4-addition, methyl (12R)-12-hydroxylabda-8(17),13E-dien-19-oate, and the hydration product of the 8(17)-double bond on the (a priori) most hindered, β side, methyl (8S)-8-hydroxylabda-12E,14-dien-19-oate.Besides these, small amounts of the double-hydration product methyl (8S)-8,14-dihydroxylabd-12E-en-19-oate were also obtained.Finally, methyl (Z)-communate 2 showed similar behaviour to its E-isomer in OM-DM reactions.
