New Indole Alkaloids from Kopsia Singapurensis (RIDL.)

Abstract

Study on chemical constituents from Kopsia singapurensis (Apocynaceae) yielded four new aspidofractinines: Singaporentine A, N(1)-formylkopsininic acid, N(1)-formylkopsininic acid-N(4)-oxide, 15-hydroxykopsamine; a new aspidospermatan: 14α-hydroxy-N(4)-methylcondylocarpine and a new akuamiline: singaporentinidine together with 18 known indole alkaloids from different parts of the plant. The structures of these compounds were elucidated by combination of various spectroscopic methods.