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

From the leaves of Oncinotis tenuiloba S TAPF , 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.