The structure of laricinolic acid and its biomimetic transformation into officinalic acid

Methoxylaricinolic Acid, a New Sesquiterpene from the Fruiting Bodies of Stereum ostrea

“…The 1 H and 13 C NMR spectra (Table 1) in the aid of DEPT and HMQC data revealed the presence of one exocyclic double bond (C-8 and C-12), three methyls (C-13, C-14 and C-15), four methylenes (C-1, C-2, C-3 and C-6), three methines (C-5, C-7 and C-9) including one oxygen-bearing carbon (C-7), two quaternary carbon (C-4 and C-10) and one carbonyl carbon (C-11). These data were in good agreement with those of laricinolic acid, a sesquiterpene of the drimane type isolated from the woodrotting fungus Laricifomes officinalis [9]. 2 was confirmed to be identical to laricinolic acid by interpretation of HMBC, which exhibited the long-range correlations from 5-H to C-4, C-9, C-10 and C-13, from 9-H to C-1, C-8, C-10, C-11 and C-15, from 12-H to C-7, C-8 and C-9.…”

“…2 was confirmed to be identical to laricinolic acid by interpretation of HMBC, which exhibited the long-range correlations from 5-H to C-4, C-9, C-10 and C-13, from 9-H to C-1, C-8, C-10, C-11 and C-15, from 12-H to C-7, C-8 and C-9. Other physico-chemical properties were well matched with those of laricinolic acid [9].…”

Natural disesquiterpenoids

“…265 The assignment of the metabolite was achieved by NMR data, chemical methods, and single-crystal X-ray diffraction analyses, 266 and its absolute configuration was determined by chemical transformation. 267 Though officinalic acid was first reported as a triterpene, biosynthetically the natural product may not be derived from squalene -it is most likely that it is formed via cycloaddition dimerization of a drimane sesquiterpenoid containing an a,b-exomethylene cyclohexanone moiety. Furthermore, laricinolic acid (LCA, C 15 H 24 O 3 ), which is easily converted into a key intermediate for the biosynthetic precursor of 272, was found to co-exist in Laricifomes officinalis, demonstrating that the hypothesis is correct.…”

“…Furthermore, laricinolic acid (LCA, C 15 H 24 O 3 ), which is easily converted into a key intermediate for the biosynthetic precursor of 272, was found to co-exist in Laricifomes officinalis, demonstrating that the hypothesis is correct. 267 The biomimetic synthesis of officinalic acid was completed with the guidance of this biosynthetic hypothesis. 267,268 In the synthesis, the naturally occurring LCA was used as the starting material, which was oxidized to the rather unstable crystalline enone.…”

“…267 The biomimetic synthesis of officinalic acid was completed with the guidance of this biosynthetic hypothesis. 267,268 In the synthesis, the naturally occurring LCA was used as the starting material, which was oxidized to the rather unstable crystalline enone. The mixture, without purification, was refluxed in toluene to offer the desired product 272.…”