Our recent isolation from Evodia rutaecarpa Bentham (Rutaceae) of N-(2 methylaminobenzoyl)tryptamine E11 (1), which is possibly a key intermediate in the biosynthesis of evodiamine E21 (2), prompted us to reinvestigate the alkaloidal fraction in more detail. As a result, we wish to report the isolation and structural elucidation of a new alkaloid 3, named evodiamide, which is also considered to be a precursor of 2. Evodiamide was obtained as colorless prisms. The uv absorptions (221, 284, and 291 nm) demonstrated the presence of an indole nucleus (5). The ir spectrum showed an absorption (1620 cm-1) due to an amide carbonyl. The hrms determined the molecular formula as C19H21N3O (Δ 0.2 mmu), which differs from 1 by CH2. The appearance of a new three-proton signal (δ 3.00) in the 1H nmr spectrum strongly indicated that 3 should be an N-methyl derivative of 1. Unlike 1, however, 3 showed unusual behaviors in the 1H- and 13C-nmr spectra. Both the methyl and ethylene groups adjacent to the nitrogen of the amide appeared as extremely broadened signals (δ 3.00, 3.21, and 3.86, respectively) in the 1H-nmr spectrum. Furthermore, in the 13C-nmr spectrum, the signals expected for the two carbons next to the nitrogen function could not be found. The interpretation of these observations could be made in the terms of the influence of the amide carbonyl. Compound 3 underwent ready reduction with LiAlH4 to afford an amine 4, which gave typical 1H- and 13C-nmr spectra as expected. The final structural information of 3 was obtained by synthesis. Evodiamide was prepared with N-methyltryptamine and N-methylisatonic anhydride in the manner similar to that reported for 1 (6). The physicochemical data of the synthetic 3 were identical with those of the natural one. We propose the name evodiamide for 3, which was assigned the structure N-methyl-N-(2 methylaminobenzoyl)tryptamine. Compound 3 seems to be a precursor in the biosynthesis of 2, although it still remains to be proven experimentally.