The Stereochemistry of the Pentacyclic Oxindole Alkaloids

Shamma, Maurice; Shine, Robert J.; Kompis, I.; Sticzay, T.; Morsingh, F.; Poisson, Jacques; Jl, Pousset

doi:10.1021/ja00983a041

Cited by 43 publications

(11 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…± Oxindole alkaloids are classified in stereochemical groups with allo (rings D/E cis, C(3) (S), epiallo (rings D/E cis, C(3) (R)), and normal (rings D/E trans, C(3) (S)) configurations [16]. The pseudo (rings D/E trans, C(3) (R)) configuration, although possible for indole alkaloids, is sterically not viable for oxindoles.…”

mentioning

confidence: 99%

X‐Ray Crystal Structure Analysis of Oxindole Alkaloids

Laus

Wurst

2003

Helvetica Chimica Acta

View full text Add to dashboard Cite

The single-crystal X-ray structures of speciophylline, mitraphylline, and rhynchophylline, oxindole alkaloids from the Peruvian climbing vine Uncaria tomentosa (Rubiaceae), were determined. The three compounds show N ¥¥¥ HÀN hydrogen bonding, which has not been observed in the crystal structures of the related alkaloids pteropodine and isopteropodine. In the tetracyclic alkaloid rhynchophylline, the side chain is rotated out of the ring plane into a position perpendicular to it. This is in contrast to the situation of the pentacyclic analogue mitraphylline, which possesses a conformationally rigid tricyclic core. This conformational difference possibly causes the competitive antagonism of these two types of alkaloids.Introduction. ± The genus Uncaria (Rubiaceae) is a rich source of oxindole alkaloids. During recent years, pharmacological activities of some of these alkaloids were investigated. The tetracyclic oxindole alkaloid rhynchophylline (1) blocks the release of calcium from intracellular storage and possesses hypotensive potency [1]. Effects of 1 on contraction of isolated rat uterus, contraction of rabbit aorta, and myocardial contractility in dogs and cats were reported [2]. Negatively chronotropic and inotropic effects of rhynchophylline (1) and isorhynchophylline were observed [3]. In contrast, pentacyclic oxindole alkaloids affect the cellular immune system. They stimulate endothelial cells in vitro to produce a lymphocyte-proliferation-regulating factor [4] and stimulate interleukin-1 and -6 production by alveolar macrophages [5]. Isopteropodine (2) and pteropodine (3) enhance the phagocytic activity of granulocytes [6]. A recent study showed that the tetracyclic alkaloids antagonize the stimulating effect of the pentacyclic alkaloids [7]. Therefore, it seemed to be of interest to examine their three-dimensional structures in detail. The results of single-crystal Xray structure determinations of rhynchophylline (1), speciophylline (4), and mitraphylline (5), isolated from Peruvian U. tomentosa (Willd.) DC root [8] are presented. Crystal structures were reported earlier for pteropodine hydrate [9], isopteropodine, and the CHCl 3 solvate of pteropodine [10], and the related isorhynchophyllic acid from U. sinensis (Oliv. ) Havil. [11]. Mitraphylline was also detected in leaves of U. quadrangularis Geddes ( U. homomalla Miq.), U. attenuata Korth., U. orientalis Guill., U. velutina Havil., U. perrottetii (A. Rich. ) Merr., in the root of U. guianensis (Aubl.) Gmel., and in the bark of U. elliptica R. Br. [12] [13]. Speciophylline, pteropodine, and isopteropodine were also identified in the leaves of U. homomalla, U. lanosa var. glabrata (Bl.) Ridsd., U. sinensis, and U. orientalis [12] [14]. Rhynchophylline (1) was also found in the leaves of U. borneensis Havil., U. longiflora (Poir.) Merr., U. guianensis, U. macrophylla Wall., in aerial parts of U. rhynchophylla Miq., and in the stem bark and hooks of U. attenuata [12] [15].

show abstract

mentioning

confidence: 99%

X‐Ray Crystal Structure Analysis of Oxindole Alkaloids

Laus

Wurst

2003

Helvetica Chimica Acta

View full text Add to dashboard Cite

show abstract

“…The correlation shown between protons of C-5 and C-6 with the quaternary carbon at δ 56.34 confirmed its position at C-7 (See Figure 1). The relatively low field 18-H 3 signal at δ 1.44 ( J = 6 Hz), alkaloid 1 represents an allo -type isomer due to the close proximity of the 18-H 3 to N b lone pair electrons [10,11]. Two allo -type streoisomers are possible for alkaloid 1 ; rauniticine- allo -oxindole A and rauniticine- allo -oxindole B, since the NMR characteristics of pteropodine and isopteropodine had been well established [4,8,10].…”

Section: Resultsmentioning

confidence: 99%

Rauniticine-allo-Oxindole B and Rauniticinic-allo Acid B, New Heteroyohimbine-Type Oxindole Alkaloids from the Stems of Malaysian Uncaria longiflora var. pteropoda

et al. 2011

View full text Add to dashboard Cite

show abstract

“… Spirotryprostatins A and B [ 89 ], pteropodine and isopteropodine [ 90 ], rhynchophylline [ 91 ] and formosanine [ 92 ]. …”

Section: Figures Schemes and Tablesmentioning

confidence: 99%

Gold Catalyzed Multicomponent Reactions beyond A3 Coupling

et al. 2018

View full text Add to dashboard Cite

The preparation of complex architectures has inspired the search for new methods and new processes in organic synthesis. Multicomponent reactions have become an interesting approach to achieve such molecular diversity and complexity. This review intends to illustrate important gold-catalyzed examples for the past ten years leading to interesting skeletons involved in biologically active compounds.

show abstract

The Stereochemistry of the Pentacyclic Oxindole Alkaloids

Cited by 43 publications

References 0 publications

X‐Ray Crystal Structure Analysis of Oxindole Alkaloids

X‐Ray Crystal Structure Analysis of Oxindole Alkaloids

Rauniticine-allo-Oxindole B and Rauniticinic-allo Acid B, New Heteroyohimbine-Type Oxindole Alkaloids from the Stems of Malaysian Uncaria longiflora var. pteropoda

Gold Catalyzed Multicomponent Reactions beyond A3 Coupling

Contact Info

Product

Resources

About