Homoisoflavonoids and related compounds. II. Isolation and absolute configurations of 3,4-dihydroxylated homoisoflavans and brazilins from Caesalpinia sappan L.

Abstract

Three new phenolic compounds, 3'-Ο-methylsappanol, 3'-Ο-methylepisappanol and 3'-Ο-methylbrazilin, were isolated from Sappan Lignum, the dried heartwood of Caesalpinia sappan. The absolute configurations of sappanol, episappanol, 3'-deoxysappanol, 3'-Ο-methylsappanol, 3'-Ο-methylepisappanol, brazilin and 3'-Ο-methylbrazilin were determined by means of Horeau's partial resolution method and chemical correlations.Sappanol, episappanol, 3'-deoxysappanol, 3'-Ο-methylsappanol and 3'-Ο-methylepisappanol form a novel class of homoisoflavonoids.