Marine 4-methyl sterols: Synthesis of C-24 epimers of 4α,24-dimethyl-5α-cholestan-3β-OL and 360 MHz 1HNMR comparisons to the natural product from Plexaura homomalla

• Published in: Steroids Vol. 42; no. 2; pp. 217 - 230
• Main Authors: Dow, W.C., Gebreyesus, T., Popov, S., Carlson, R.M.K., Djerassi, Carl
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.08.1983; Elsevier Science
• Subjects: Analytical, structural and metabolic biochemistry; Animals; Biological and medical sciences; Cholestanols - chemical synthesis; Dinoflagellida - analysis; Fundamental and applied biological sciences. Psychology; Magnetic Resonance Spectroscopy; Other biological molecules; Stereoisomerism; Terpenes, steroids. Hormones; Marine environment; High performance; Vegetals; Molecular structure; Algae; Liquid chromatography; NMR spectrometry; Thallophyta; Sterol
• ISSN: 0039-128X; 1878-5867
• DOI: 10.1016/S0039-128X(83)90220-9

Comparison of the highfield 1HNMR spectrum of 4α,24-dimethyl-5α-cholestan-3β-ol isolated by open column adsorptive chromatography and reversed-phase HPLC from P. homomalla with those of the corresponding synthetic 24α and 24β compounds demonstrate that the gorgonian natural product is purely 24β, the same C-24 configuration found in sterols related to dinosterol and gorgosterol. 360 MHz 1HNMR data are also reported for synthetic 4α,24β-dimethyl-5α-cholest-22E-en-3β-ol (another P. homomalla natural product). The use of 1HNMR correlations in assigning C-24 configurations of 24-methyl marine sterols possessing various nuclei is examined and discussed. Analyses of the methyl sterol components of P. homomalla are tabulated and discussed with regard to origin and plausible biosynthetic interrelationships in light of the C-24 configurational findings.