Kauranoid Diterpenes in Ruilopezia margarita

Abstract

Four kauranoid diterpenes have been isolated from the leaves and bud stalks of Ruilopezia margarita Cuat. A light petroleum extract was treated with diluted NaOH solution to obtain neutral and acidic fractions. Silica gel/column chromatography rendered 16–α–hydroxy–kauran and 16–α–hydroxy–kauran–19–al from the neutral fraction. The acidic fraction yielded 16–α–hydroxy–kauran–19–oic acid and 16–α–hydroxy–kaur–9(11)–ene–19–oic acid. The latter was dehydrated with SOCl₂/Pyridine to yield a mixture of 15 and 16 kaur–dienes which upon hydrogénation with Pd/MeOH rendered (–)kaur–9(11)–ene–19–oic acid. The name Ruilopezic acid is proposed for this new kaurenic acid.

Key Word Index

Ruilopezia margarita - Diterpenes - Kaurenic Acids - Ruilopezic Acid