A recent paper by Friedrich-Fiechtl and Spiteller describes four new alkaloids from Erythrophleum guineense under the names norcassamine, norcassamidine, norethythrosuamine and dehydro-norethythrosuamine. On hydrolysis these alkaloids gave N-methylethanolamine and different diterpene acids, which were either known compounds or converted into known compounds to assign structures to the acids without ambiguity. The authors assumed the alkaloids were esters of these acids and N-methylethanolamine but provided no direct supporting evidence. We show here that the compounds described are not esters but the corresponding amides, consistent with our earlier finding that alkaloidal esters of N-methylethanolamine and ethanolamine readily rearrange to amides in alkaline solution or when chromatographed on alumina—the isolation conditions used by Friedrich-Fiechtl and Spiteller. From the bark of Erythrophleum chlorostachys, we isolated an unstable (non-crystalline) alkaloidal ester (1, norcassamidine) and its isomeric amide (2, norcassamidide), with the latter identical to Friedrich-Fiechtl and Spiteller's compound 7 (m.p. 115°, [α] -22.5° (EtOH), identical NMR and mass spectra). The structures of these compounds are based on mass spectra (both give M+ ions of the appropriate formula C₂₅H₃₅NO₅), IR, UV, and NMR spectra. We find the fragmentation patterns of ester and amide are similar but readily distinguishable: the ester (1) has an intense base peak at m/e 57, while the amide (2) has the M+ ion (m/e 421) as the base peak. Further, the ester (1) has νmax (CHCl₃): 1715 cm⁻¹ (ester carbonyls), 1640 cm⁻¹ (conj. C=C), 1160 cm⁻¹ (ester C-O stretch), while the amide (2) has νmax (CHCl₃): 1720 cm⁻¹ (C-4 ester carbonyl), 1645 cm⁻¹ (conj. C=C), 1605 cm⁻¹ (amide), and no intense 1160 cm⁻¹ band. The UV absorption of ester (1) has λmax (EtOH) 224 nm (log ε 4.18), while the amide has λmax (EtOH) 213 nm (log ε 4.12). The chemical shifts of the N-CH₃, N-CH₂, and O-CH₂ hydrogen atoms clearly distinguish between ester and amide series of compounds from Erythrophleum species, and the chemical shift of the olefinic hydrogen at C-18 provides another useful criterion (Table 1). Despite the influence of methylation degree, N-CH₃ shifts fall within 2.25–2.47 for esters and 3.05–3.08 for amides. The N-CH₂ and O-CH₂ signals are widely separated and well-resolved triplets in esters (ranges δ 2.55–2.84 and 4.15–4.20, respectively) but slightly overlap in amides, forming a broad envelope between δ 3.3 and 4.0 that is poorly resolved and partly obscured by signals from methoxycarbonyl (when present) and hydrogen atoms on C-3/C-7 (when carrying hydroxyl groups). Data for (1) and (2) confirm their ester and amide character, respectively. We propose naming (1) norcassamidine and (2) norcassamidide (including Friedrich-Fiechtl and Spiteller's compound 7). The chemical shifts quoted by Friedrich-Fiechtl and Spiteller for the N-CH₃ and C₁₈H hydrogen atoms of "norcassamine" and "norerythrosuamine" are sufficient evidence of amide structures (Table 1). "Norcassamine" is identical to the amide cassamide (3) isolated from E. ivorense by Crönlund and Sandberg, who established its amide character via resistance to alkaline methanol hydrolysis, IR amide bands, and NMR signal assignments matching Table 1. No NMR data were given for "dehydro-norerythrosuamine," but its structural relation to "norerythrosuamine" via oxidation suggests it is likely (5). A confusing situation in the literature arises from the naming of amides from E. ivorense (cassanide, erythrophlanide, cassaide), which are not isomers of related amines but have one less N-methyl group. Given the isolation of isomeric pair norcassamidine (1) and norcassamidide (2), we suggest renaming E. ivorense amides norcassanide, norerythrophlanide, and norcassaide for clarity. In all Erythrophleum amide spectra we measured in CDCl₃ at 30–35°, the H-18 and N-methyl signals are doubled (sometimes degenerating to broad singlets at higher temperatures). Crönlund and Sandberg noted occasional doubling of H-18 signals in (nor)cassaide, (nor)erythrophlanide, and (nor)cassanide, suggesting cis/trans isomers or amide nitrogen configurational isomerism. A study on norcassamidide shows these signals are temperature-dependent: double peaks disappear with increasing temperature, supporting rotational isomerism due to restricted C-N amide linkage movement. By 50°, only single broad peaks at δ 5.82 and 3.02 were observed, becoming sharp singlets by 100°, while the 3.3–3.9 multiplet resolved more clearly.