PMID: 30807007Sep 1, 2016Paper

On the Allylic Oxidation of Ent-kaurenic Acid Methyl Ester with Lead Tetra-acetate

Natural Product Communications
Julio RojasAlfredo Usubillaga

Abstract

In this paper, results obtained upon treatment of the methyl ester of ent-kaur-16-en-19-oic acid (1b) with lead tetra-acetate under reflux in glacial acetic acid solution and an argon atmosphere are described. After 30 minutes reflux, GC-MS analysis of the product indicated the presence of three substances, the initial compound (1b, 7 %), the methyl ester of ent-kaur-16-en-15-O-acetyl-19-oic acid (2a, C₂₃H₃₀0₄, 45 %), and its isomer, the methyl ester of ent-kaur-15-en-17- 0-acetyl-19-oic acid (3a, 47 %). Flash chromatography over silica gel containing 20% AgNO₃ yielded 2b (456 mg), which was identified by direct comparison with an authentic sample, and 3a (472 mg), whose structure was established by uni- and bi-dimensional NMR analysis. Hydrolysis of 3a with dry ammonia in MeOH yielded the methyl ester of ent-kaur-15-en-17-hydroxy-19-oic acid (3b, C₂₁H₃₂ 0₃); treatment of this compound with chromic acid/pyridine complex rendered the aldehyde (4).

Related Concepts

Related Feeds

Alternative Complement Pathway

The Alternative Complement Pathway is part of the innate immune system, and activation generates membrane attack complexes that kill pathogenic cells. Discover the latest research on the Alternative Complement Pathway.

Related Papers

Natural Product Communications
Julio RojasAlfredo Usubillaga
Il Farmaco; edizione scientifica
F DE LORENZI, R ALDROVANDI
The Journal of Histochemistry and Cytochemistry : Official Journal of the Histochemistry Society
R D LILLIE, G G GLENNER
© 2022 Meta ULC. All rights reserved