Die Struktur des Spermin‐Alkaloides Aphelandrin aus Aphelandra squarrosa NEES. 170. Mitteilung über organische Naturstoffe

Abstract

The structure of the spermine alkaloid aphelandrine from Aphelandra sguarrosa NEES SummaryThe new spermine alkaloid aphelandrine (2) has been isolated from Aphelandra squarrosa NEES. By oxidation of 2 with KMn04 followed by methylation (CH2N2) 12 and 14 could be prepared (Scheme 2). Fusion of 2 with KOH yielded spermine (1) whereas hydrolysis of 2 in hot hydrochloric acid results in lacton 17, the structure of which could be elucidated by comparison with a synthetically prepared model compound (Scheme 3). The benzylic bonds N (lo), C (1 1) as well as 0 (16), C (17) of 2 could be cleaved by hydrogenolysis (compare 23 and 26; Scheme 4). The elucidation of the correct linkage of the spermine moiety with the aromatic dicarboxylic acid is based mainly on chemical and spectroscopic evidence of the tetrahydro derivative 26, the Hofmann-degradation products 28,30 and 31 (Scheme 6) as well as the ester 35, prepared by partial hydrolysis of 2 (Scheme 7).

Detection and Characterization of Natural Polyamines by High-Performance Liquid Chromatography-Atmospheric Pressure Chemical Ionization (Electrospray Ionization) Mass Spectrometry

“…This kind of investigation has confirmed, for instance, the biogenic structural units of aphelandrine, the major macrocyclic spermine alkaloid in the roots of several Aphelandra species. [24][25][26] The approximately 165 known species of the genus Aphelandra are distributed from southern Mexico to Argentina at elevations between sea level and 4000 m. The roots of several species of this genus contain aphelandrine, [27][28][29] and biosynthesis, accumulation and metabolism of aphelandrine in some Aphelandra species have been investigated by online coupled HPLC-UV(DAD)-APCI-MS. [30][31][32] By means of this technique not only could the structures of new macrocyclic alkaloids be successfully elucidated but the possible key role of some of the intermediates in their biosynthesis has been proposed. 31 Although putrescine, spermidine and coumaric acid were concluded to be the building blocks of aphelandrine (6) (Scheme 4), it was not clear whether mono-or dicoumaroylspermine is its precursor.…”

Phenol oxidative coupling in the biogenesis of the macrocyclic spermine alkaloids aphelandrine and orantine in Aphelandra sp.

“…Aphelandrine (1) (Fig. 1) has been found as the major alkaloid in the roots of several Aphelandra species together with orantine (2) DaÈ twyler et al 1978;Youhnovski et al 1999). The upper part of the plant and cell cultures of A. tetragona and A. sinclairiana are completely devoid of this type of alkaloid (Nezbedova et al 1999).…”

Biogenesis and function of macrocyclic spermine alkaloids

“…The main alkaloids of this genus, aphelandrine (9) and its diastereoisomer orantine (10), were isolated from the roots of different Aphelandra species. 4,5 In addition, orantine (ephedradine A, 10) was isolated from…”