In the title compound (5S,8R,9R,10R,13S,14S,17R,20R)-24-bromo-5β-cholane, C(24)H(41)Br, the fused-chair conformation of the cyclo-hexane A/B ring junction is cis with a 5β-H configuration.
The mol-ecule of accanthomine A, C(15)H(13)N(5), is approximately planar, with the indolyl fused-ring and the pyrimidyl ring being twisted by 31.7 (1)° The amino group of the five-membered ring is an intramolecular hydrogen-bond donor to a nitro-gen acceptor of the pyrimide ring. The amino group of the pyrimide ring is a hydrogen-bond donor to the N atoms of adjacent mol-ecules. These hydrogen-bonding inter-actions give rise to a layered network with a 4.8(2) topology.
In the title steroid derivative, C(25)H(40)O(3), the fused cyclo-propane unit that corresponds to a part of the A ring has a β-configuration and the associated cyclo-pentane ring an envelope-shaped conformation.
In the crystal structure of 2-bromo-beclometasone dipropionate [systematic name: (8S,9R,10S,11S,13S,14S,16S,17R)-2-bromo-9α-chloro-11-hydr-oxy-10,13,16-trimethyl-3-oxo-17-[2-(propion-yloxy)acet-yl]-6,7,8,9,10,11,12,13,14,15,16,17-dodeca-hydro-3H-cyclo-penta-[a]phenanthren-17-yl propionate], C(28)H(36)BrClO(7), the six-membered ring with the 1,4-diene-3-one composition is planar (r.m.s. deviations = 0.03 and 0.04 Å for the two independent mol-ecules), whereas the remaining six-membered rings have chair conformations. Each of the independent mol-ecules self-associates via O-H⋯O(propionate) hydrogen bonding, generating a supra-molecular chain running along the b axis. The crystal is twinned, with the monoclinic unit cell emulating an orthorhomic crystal system; the major twin component constitutes approximately 60%.
In the crystal structure of (8S,9R,10S,11S,13S,14S,16S,17R)-9α-bromo-11-hydr-oxy-10,13,16-trimethyl-3-oxo-17-[2-(propion-yloxy)acet-yl]-6,7,8,9,10,11,12,13,14,15,16,17-dodeca-hydro-3H-cyclo-penta-[a]phenanthren-17-yl propionate monohydrate, C(28)H(37)BrO(7)·H(2)O, which has a 9α-Br atom in place of the 9α-Cl atom of monohydrated beclometasone dipropionate, one six-membered ring is planar (r.m.s. deviation = 0.02 Å) owing to its 1,4-diene-3-one composition, whereas the two other six-membered rings each have a chair conformation. The organic mol-ecule and water mol-ecules engage in hydrogen-bonding inter-actions, generating a helical chain running along the c axis of the ortho-rhom-bic unit cell.
The title compound, C(28)H(34)Cl(2)O(7), is a derivative of the glucocorticoid steroid beclomethasone dipropionate. It features an expoxide linkage [angle at oxygen = 96.6 (2)°]. The dichlorocyclohexenone ring adopts an envelope conformation, with the C atom bearing the two Cl substituents representing the flap. The dichloro-methyl C atom deviates by 0.471 (4) Å from the plane defined by the other five atoms, whose maximum r.m.s. deviation is 0.04 Å.
In the title compound, C(18)H(21)IO, the cyclo-hexane ring adopts a chair conformation, whereas the cyclo-pentane ring and the ten-membered tetra-line portions each adopt an envelope conformation. For the five-membered ring, the methine C atom deviates by 0.638 (4) Å (r.m.s. of the four other atoms is 0.005 Å) and for the ten-membered ring, the methine C atom constituting the flap deviates by 0.671 (3) Å (r.m.s. of the other nine atoms is 0.066 Å).
The bark of Cryptocarya crassinervia provided two new phenantrene alkaloids, 2-hydroxyatherosperminine (1) and N-demethyl-2-methoxyatherosperminine (2).
The phytochemical study of the bark of Malaysian Phoebe scortechinii (Lauraceae) has resulted in the isolation and identification of two new proaporphine alkaloids; (+)-scortechiniine A (1) and (+)-scortechiniine B (2) together with two known proaporphines; (-)-hexahydromecambrine A (3), (-)-norhexahydromecambrine A (4), and one aporphine; norboldine (5). Structural elucidations of these alkaloids were performed using spectroscopic methods especially 1D and 2D (1)H and (13)C NMR.
The asymmetric unit of the title compound, C(29)H(50)O(2), contains two mol-ecules; one mol-ecule is linked to the other by two O-H⋯O hydrogen bonds, whereas only one of the hydr-oxy groups of the second mol-ecule is involved in hydrogen bonding. This gives rise to a chain that runs along the a axis of the monoclinic unit cell.
The title compound, C(30)H(34)O(5), crystallizes with two symmetry-independent mol-ecules in the asymmetric unit. In the crystal structure, the two independent mol-ecules are disposed about a pseudo-center of inversion. An intra-molecular O-H⋯O hydrogen bond is observed in each independent mol-ecule. The crystal structure is stabilized by C-H⋯O hydrogen bonds.
The hydr-oxy groups in the title compound, C(16)H(14)O(4), are each hydrogen bonded to the adjacent meth-oxy O atom; one of the two hydr-oxy groups is additionally linked to the O atom of the meth-oxy group of another mol-ecule, forming a linear chain.
Five new cytotoxic limonoids, erythrocarpines A-E (1-5), were isolated from the bark of Chisocheton erythrocarpus Hiern. Chemical structures, stereochemistry, and conformation were fully elucidated and characterized by 2D NMR, MS, and computational methods.
The leaves of the Phoebe scortechinii (Gamb.) Kochummen Comb. Nov. (Lauraceae), afforded one new proaporphine-tryptamine dimer; (-)-phoebescortechiniine (1), along with two known ones; phoebegrandine A and phoebegrandine B. The proaporphine, tetrahydropronuciferine (2), was isolated for the first time as a natural product. The alkaloids were elucidated primarily by means of high field NMR and HRMS.
The alkaloidal extract of the leaves of Phoebe grandis (nees) merr. have provided two new minor alkaloids; phoebegrandine D (1), a proaporphine-tryptamine dimer, and phoebegrandine E (2), an indoloquinolizidine. This is the first report on the occurrence of an indoloquinolizidine in the Phoebe species. The crude extract also exhibited antiplasmodial activity (IC50<8 microg mL-1). The structures of the novel compounds were elucidated by spectroscopic methods, notably 2D NMR and HRMS.
Five morphinoid alkaloids have been isolated from Dehaasia longipedicellata, namely (-) pallidine, a new alkaloid (+) pallidinine (1), (+)-milonine, (-) 8,14-dehydrosalutaridine and (-) sinoacutine.
A novel proaporphine-tryptamine dimer alkaloid, named phoebegrandine C 1, was isolated from the leaves of Phoebe grandis (Nees) Merr. Its structural elucidation was carried out using spectroscopic techniques, notably 2D NMR.
Bioassay-guided fractionation of an ethyl acetate extract of Fissistigma lanuginosum led to the isolation of the known chalcone pedicin [1], which inhibited tubulin assembly into microtubules (IC50 value of 300 microM). From the same EtOAc fraction, two new condensed chalcones, fissistin [2] and isofissistin [3], which showed cytotoxicity against KB cells, were also obtained, together with the inactive dihydropedicin [4] and 6,7-dimethoxy-5,8-dihydroxyflavone [5]. In addition, the aminoquinones 6, 8, and 9 were isolated from the alkaloid extract. These compounds were artifacts, prepared by treatment of 1, 4, and 2, respectively, with NH4OH. The structures of the new compounds were elucidated by spectral methods, especially 2D nmr.
Bioassay-guided fractionation of the extracts of Zieridium pseudobtusifolium and Acronychia porteri led to the isolation of 5,3'-dihydroxy-3,6,7,8,4'-pentamethoxyflavone [1], which showed activity against (KB) human nasopharyngeal carcinoma cells (IC50 0.04 micrograms/ml) and inhibited tubulin assembly into microtubules (IC50 12 microM). Two other known flavonols, digicitrin [2] and 5-hydroxy-3,6,7,8,3',4'-hexamethoxyflavone [5], were also isolated together with three new ones, 3-O-demethyldigicitrin [3], 3,5,3'-trihydroxy-6,7,8,4'-tetramethoxyflavone [4], and 3,5-dihydroxy-6,7,8,3',4'-pentamethoxyflavone [6]. All of these flavonols showed cytotoxic activity against KB cells.
Crude glycoside extracts from the plant, Sarcolobus globosus, were tested on the rat phrenic nerve-diaphragm, chick biventer cervicis and frog rectus abdominis preparations. Nerve-stimulated twitches were inhibited by the extract. The muscle paralysis was not similar to that by curare-like blockers as it was not reversed by neostigmine or by a tetanus. Although contractures to acetylcholine or carbachol were not affected by 0.6 mg/ml of the extract, higher concentration of the extracts (3 mg/ml) depressed the log dose-response curve of acetylcholine and carbachol. The results suggest that the neuromuscular blocking effect of the extracts is either dose-dependent or due to a mixture of toxins with presynaptic or postsynaptic actions.