Heptelidic acid

Abies halsamea Phyllosticta sp. hydro- and heptelidic acid, heptelidic acid chlorhydrin 203... 

Fig. 9.33. Chromatograms illustrating the spectrum of applicability of chiral anion exchangers derived from cinchonan derivatives (reprinted with permission from Ref. 1388]) (mobile phase McOH-O.l M ammonium acetate (80 20) pHj = 6.0 T = 25°C flow rate. I ml/min UV detection) (unless otherwise stated), (a) r7.v-3-Aminocyclopentanc carboxylic acid as DNZ derivative on CSP 1. (b) Heptelidic acid on CSP Vll T = I0°C. (c) 2-(rm-Butylsulphonylmethyl) 3-phcnyl propionic acid on CSP IX. (d) Camphor-10-sulphonic acid on CSP II. (e) 3-(3-Carboxy-pipcrazin-I-yl)propyIphosphonic acid as DNP-dcrivative mobile phase MeOH-0.5 M ammonium acetate (90 10) pH., = 6.0. (f) Omcpra/ole on CSP IX mobile phase. ACN-O. I M ammonium acetate (65 35) pH., = 5.0 T = 0"C. (g) 3,4-Dihydro-2H-pyran-2-carboxylic acid (reprinted with permis.sion from Ref. [73]) (for structure of CSPs see Fig. 9.32).

Studies of the biosynthesis of heptelidic acid indicate that cis, trans-farnesyl diphosphate can act as the biosynthetic precursor (Scheme 20). Ring closure is initiated by a stereospecific 1, 3-hydride shift during which the methyls of the isopropyl group retain their identity [194, 195, 198]. The remaining sequence as shown in the Scheme also includes a rationalization for the generation of gliocladic acid (141) and the hydroxy acid (139). It should be mentioned that the evidence for structure 139 is lacking [206], but it appears to be an acceptable structure insofar as it is... 

Compounds with rearranged cadinane skeletons include the fungal antibiotic heptelidic acid (203), the most unusual endo-peroxide qinghaosu (204), which is an active principle from the Chinese medicinal herb Artemisia annua L., and koidzumiol (205). The biogenesis of the latter compound is considered to be as shown in Scheme 24. Some further derivatives of abrotanifolone (206) have also been isolated. ... 

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