Höhere Terpenverbindungen XLVIII. Über die Konstitution der durch Oxydation der Abietinsäure gewonnenen Tricarbonsäuren C₁₁H₁₆O₆ und C₁₂H₁₈O₆. Ein Beitrag zur Kenntnis des Kohlenstoffgerüstes der Abietinsäure

Abstract

wird abgekiihlt und in Eiswasser gegossen. Durch wiederholtes Cmkrystallisieren aus lVIethylalkoho1 erhalt man posse Prismen vom Smp. 94,5-95,s0 und hellgelber Farbe. 20,535 mp Subst. qaben 36,810 mq CO, und 4,915 mg H,O 35,150 mg Subst. gaben 4,7 cm3 X2 (19O. i l 5 mm) C,H,O,N,CI Bei. C 28,86 H 2,5i

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“…Other evidence for the position of the carboxy group and quaternary methyl group came from the energetic oxidation of abietic acid to two homologous tricarboxylic acids shown by further degradation to be 37 and 38. 45 Vigorous oxidation to identifiable fragments was an important strategy which complemented dehydrogenation. These acids were also to play an important part later in the determination of the stereochemistry of the diterpenoids.…”

The acids of pine oleoresin and rosin

“…From their behavior on dehydrogenation (discussed above), these acids are concluded to have a decahydrophenanthrene nucleus to which at least one methyl group and an isopropyl group are attached in abietic acid and two methyl groups in (Z-pimaric acid (see Figure 3). Energetic oxidation of the acids with permanganate or with nitric acid is productive of a number of interesting compounds, particularly the two tri-carboxylic acids: CnHi606 (V, Figure 3) and its homolog CnsHigOe (VI, Figure 3) (55,58). These tricarboxylic acids are obtained from both abietic and <Z-pimaric acid since the same structure characterizes the first two rings in both.…”