Alstonia scholaris: The structure of the indole alkaloid nareline Besides the known akuammidine, picralinal, picrinine and pseudoakuammigine a new indole alkaloid called nareline (M=352) was isolated from Alstonia scholaris R. BR., which belongs to the plant family of Apocynaceae. Its structure 2 was deduced by single crystal X‐ray diffraction. 2 represents the absolute configuration. The spectroscopic data of 2 and its derivatives Scheme 1 as well as their chemical behavior support this structure. In biogenetic sense nareline is related to the bases akuammiline (4) and picraline (5) Scheme 2. In contrast to those the C‐atom 5 is exocyclic and represents an aldehyde group which forms together with the oxygen atom of the N (4)‐hydroxylamine group a cyclic half acetale. ‐ By oxidation (CrO3/CH3COOH) of 2 the oxindol derivative 19 (oxonareline) is formed which contains a cyclic acetal as a partial structure element Scheme 4. Copyright © 1977 Verlag GmbH & Co. KGaA, Weinheim