Synthesis of Tenuilobine,a Bis-polyamine Alkaloid from Oncinotis tenuiloba,and Its Transamidation to Isotenuilobine

From the leaves of Oncinotis tenuiloba STAPF , a novel polyamine alkaloid, tenuilobine ( 9 ), was isolated. This paper presents the synthesis of 9 , as well as the base-catalyzed Zip reaction of 9 , leading to the transamidation product isotenuilobine ( 10 ). The structure of 10 was further confirmed by 2D-NMR correlation spectroscopy. For analytical purposes, the bis-polyamines 9 and 10 were converted into their pentaacetyl derivatives 12 and 11 , respectively, which were readily separable by reverse-phase HPLC.