New Alkaloids of the ent-Kaurene Type from Anopterus Species. III. A 2D-N.M.R. Study of Anopterine and the Determination of Structure of Six Minor Alkaloids by N.M.R

Abstract

A number of homonuclear and heteronuclear 2D-n.m.r. techniques have been used to interpret completely the 1H n.m.r . spectrum and to reinterpret the 13C n.m.r . spectrum of the alkaloid anopterine. Comparison of the n.m.r . data for anopterine with those of six minor alkaloids from Anopterus macleayanus has allowed the assignment of the structures, 7β-hydroxyanopteryl 11α,l2α-ditiglate, 7β-hydroxyanopteryl 11α-(E)-4′-hydroxy-2′-methylbut-2′-enoate 12α-tiglate, anopteryl 12α- tiglate , anopteryl 11α-4′-hydroxybenzoate 12α-tiglate, 7β- hydroxyanopteryl 11α-4′-hydroxybenzoate 12α-tiglate and 7β- hydroxyanopteryl 11α-benzoate 12α-tiglate to the minor alkaloids.