Die Alkaloide aus Hedranthera barteri (Hook. f.) Pichon. 139. Mitteilung über Alkaloide

Abstract

Summary. From the root bark of the apocynacea Hedranthera barteri (Hook: f.) Pichon were isolated the known indole alkaloids vobtusine (I), voacamine (2), callichiline (3), voacanghe (4) and conoflorine (5). as well as the unknown plant bases amataine, goziline and owerreine, and also beninine and 1,2-dehydrobeninine. The structures of the two last mentioned alkaloids were shown in an earlier publication to be 6 and 7, respectively. Amataine, goziline and owerreine are bis-indole alkaloids, which on the basis of their chemical and spectroscopic (especially mass spectroscopic) properties have been assigned the structures 8, 9 and 10, respectively.Aus der Wurzelrinde der Apocynacee Hedranthera barteri (Hook. f.)In der vorliegenden Arbeit berichten wir uber die Isolierung von sechs weiteren Basen. Teil der Dissertation V . Agwada, Universitat Ztirich.In [3] als Callinin bezeichnet.

Macrocarpamin, ein neues Bisindolalkaloid aus Alstonia macrophylla WALL. 167. Mittelung über organische Naturstoffe

“…2). 2,7-Dihydropleiocarpamin (4) weist in dem betrachteten Absorptionsbereich 2,40-3,40 ppm sieben Signale auf [lo]; es sind dies: Die Signale von H-C (2,3,7,15), 2 H-C(5) und H,-C(21). Zusammen rnit den drei Protonen-Signalen der Spaltbase 5 ergibt dies 10 H, also eines mehr als im Spektrum von 3.…”

Voacanga alkaloids. 16. Carbon-13 nuclear magnetic resonance spectroscopy of naturally occurring substances. 43. Carbon-13 nuclear magnetic resonance analysis of bis-indoline alkaloids of two voacanga species

“…2a,Y = H 3a,A14,ls b, Y = OMe b,14/3,15/?-oxide Since the three indole alkaloid "dimers" are 14,14-disubstituted 11-demethoxyvandrikines (2a), comparison of their 13C NMR spectra with those of vandrikine (2b)9 and tabersonine (3a)9 allows direct signal matching for all carbons of ring A, B, C, and E. Whereas C(17) can be confused with C(14/) in vobtusine (la), the ambiguity is relieved on comparison of the shifts of like carbons in the lactones. The identification of vobtusine's C (18) and C (19) shifts and their distinction from the similar C(18') and C (19') shifts rest on the values of like carbons in the monomer vandrikine (2b) and the modification of the latter pair on introduction of the lactone carbonyl group.…”

“…The drastic shift perturbations of the carbons of rings C, D, E, and the D-attached tetrahydrofuran cannot be accommodated by a H(3a) configuration, since this stereochemistry, depicted in conformation 12, introduces merely a ring F/ boat form into the skeleta of the 2'-hydroxy-14-iso compounds, thus affecting, at worst, only the C(3), C(5), C( 14), C(15), and C (21) shifts. More deep-seated conformational changes must be involved in shift alteration of centers far removed from the ether-bridging site, such as the lower limit <5 values of 3, 4, 6, and 4 ppm for C(6), C(7), C(17), and C (19), respectively. Thus it appears that folicangine, subsessiline, and subsessiline lactone possess a H(3|3) configuration, as illustrated in formulas 10,11a, and lib.…”

“…Received March 22,1976 The Melodinus C4i alkaloids scandomelonine and episcandomelonine are shown by 13C NMR spectroscopy to be 19 epimers of 10-(3'a-pachysiphinyl)meloscandonine. A similar study of the C42 Melodinus bases scandomeline and episcandomeline reveals them to be structurally related, 19-epimeric carbinolamines.…”

Total Syntheses of (−)-Deoxoapodine, (−)-Kopsifoline D, and (−)-Beninine

“…Several groups have worked on its chemical synthesis . (−)-Beninine ( 4 ) was originally isolated from Callichilia barteri PICHON in 1966, and analysis of its spectral data led to its proposed structure as shown in Figure . The core frameworks of these two alkaloids feature a fused hexacyclic ring system bearing four or five contiguous stereocenters, of which two are all-carbon quaternary stereocenters.…”