Study of the Acid-Catalyzed Isomerization of Dihydroveatchine

• Published in: Journal of natural products (Washington, D.C.) Vol. 60; no. 7; pp. 684 - 687
• Main Authors: Desai, Haridutt K, Bai, Yili, Pelletier, S. William
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 01.07.1997; Amer Chemical Soc; American Society of Pharmacognosy
• Subjects: Alcaloids; aldehidos; aldehyde; aldehydes; Alicyclic compounds, terpenoids, prostaglandins, steroids; Alkaloids - chemistry; Analytical, structural and metabolic biochemistry; biochemical pathways; Biological and medical sciences; biosintesis; biosynthese; biosynthesis; Catalysis; chemical reactions; chemical structure; Chemistry; Chemistry, Medicinal; diterpenoide; diterpenoids; diterpenos; espectrometria; estructura quimica; Exact sciences and technology; fisiologia vegetal; Fundamental and applied biological sciences. Psychology; Heterocyclic compounds, pigments; isomerisation; Isomerism; isomerizacion; isomerization; Life Sciences & Biomedicine; Magnetic Resonance Spectroscopy; Organic chemistry; Other biological molecules; Pharmacology & Pharmacy; physiologie vegetale; plant physiology; Plant Sciences; Preparations and properties; reacciones quimicas; reaction chimique; Science & Technology; spectrometrie; spectrometry; Spectrometry, Mass, Fast Atom Bombardment; structure chimique; Terpenoids; via bioquimica del metabolismo; voie biochimique du metabolisme; ALKALOIDS; Pentacyclic compound; Alkaloid; Terpene; Aminoalcohol; Nitrogen heterocycle; Isomerization; Diterpene; Alcohol; Acid catalysis; Aldehyde
• ISSN: 0163-3864; 1520-6025
• DOI: 10.1021/np9701440

A study of the acid-catalyzed isomerization of dihydroveatchine (5) resulted in the isolation of a single major compound, the aldehyde 6. Structure 6 has been derived from its spectral data. Reduction of 6 with NaBH4 gave compound 7, which was characterized through detailed NMR studies including 1D, 2D, and selective INEPT experiments, as well as preparation of its mono- and bis(p-nitrobenzoyl) derivatives 8 and 9. A plausible mechanism for the formation of 6, derived from the spectral data of the isomerized product obtained by deuterium labeling, is reported. Interestingly, the acid-catalyzed isomerization products of the allylic alcohols garryfoline (1) and dihydroveatchine (5) are different and appear to be dependent on the configurational orientation of the C(15) hydroxyl group. Unambiguous NMR chemical shift assignments for 5 are also reported.