Extractives of Mammea americana L. Part II. The 4-phenylcoumarins. Isolation and structure of Mammea A/AA, A/A cyclo D, A/BA, A/AB, and A/BB

Abstract

In addition to the four 4-n-alkyl coumarins considered in Part I, five 4-phenyl-5,7-dioxygenated coumarins have been isolated from Mammea americana L. seeds. Two of them, A/AA and A/A cyclo D, are shown to be identical with mammeisin and mammeigin, respectively. The three new isomeric coumarins A/BA, A/AB, and A/BB are shown, by a combination of spectral data (mass, n.m.r., infrared, and ultraviolet), to possess 3-methylbut-2-enyl groups at position 6 (A/BA and A/BB) or 8 (A/AB) and to have a 3-methylbutyryl (A/BA) or a 2-methylbutyryl (A/AB and A/BB) group in the remaining phloroglucinol position. Spectral data for model compounds, synthesised to assist solution of the orientation problem, are described, and evidence is given supporting the structural assignment for mesuol. 2-Methoxyxanthone and the triterpene friedelin were also isolated.