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Johns SR, Lamberton JA, Sioums AA.
“Laurotetanine and N-MethylLauroTetanine from Palmeria fengeriana Perk (Family Moniaceae)”.
Aust J Chem. 1967;20:1787.
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Abstract
Dried milled bark (3 kg) from P. fengeriana was extracted by continuous percolation with ethanol at 40C. The crude alkaloids (4.8g ) were isolated by the method previously described, and the alkaloids were separated by chromatography on alumina previously treated with ethyl acetate
and dried in vacuum at 100'. N-Methyllaurotetanine was eluted with benzene/chloroform, and laurotetanine with chloroform and chloroform/methanol. The benzene/chloroform fractions (10% of the total alkaloids) consisted of N-methyllaurotetanine (11), which was obtained as a colourless gum, [aID +82' (c, 0.55 in CHCI,), and was shown to be homogeneous by thin-layer chromatography. The alkaloid was characterized by its 60-Mo/s n.m.r. spectrum (CDC1, solution)
which showed a three-proton singlet at 6 2.50 (NCH,), a six.proton singlet at 6 3.85 (C 2, C 10 methoxyl groups), a three-proton singlet at 6 3.63 (C 1 methoxyl group), and three singlet signals for the aryl protons at 6 8.02 (C l l ) , 6 6.65 (C 3), and 6 6.73 (C 8). Its identification was confirmed by comparison (by t.l.c., i.r., u.v., and n.m.r, spectra) with a sample of N-methyllaurotetanine prepared by heating laurotetanine in a mixture of formic acid and formaldehyde.
The chloroform and chloroform/methanol fractions (c. 80% of the total alkaloids) consisted of laurotetanine which could not be induced to crystallize but was obtained as a colourless friable foam. It was shown to be a single compound by t.l.c., and by conversion in quantitative yield
into N-acetyllaurotetanine, m.p. 143O, [a]= +331° (c, 0.12 in CHCI,), which was identified by comparison with an authentic specimen of N-acetyllaurotetanine. There was no depression of melting point on mixing the two specimens, and their i.r. and n.m.r. spectra were identical.
The authors are indebted to Dr T. G. Hartley for the collection of P. fengeriana near the village of Omaura in the Eastern Highlands District of the Territory of New Guinea, and for the botanical indentification.
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