Showing papers on "Amaryllidaceae Alkaloids published in 2007"
TL;DR: Structural-activity relationships demonstrated the requirement for both an alpha-C2 bridge and a free hydroxyl at the C-11 position as pharmacophoric requirements for the selective apoptosis-inducing activity of crinane alkaloids.
94 citations
TL;DR: One of the new alkaloids, galanthindole, which possesses a nonfused indole ring, unlike the already known subgroups of Amaryllidaceae alkaloid, may be considered as the prototype of a third new subgroup of the AmaryLLidaceaeAlkaloids.
Abstract: The Amaryllidaceae alkaloids, represent a group of isoquinoline alkaloids, which are produced almost solely by members of the Amaryllidaceae family. The alkaloids of this family have attracted considerable amount of interest due to some important pharmacological activities they were shown to possess. In the last decade, our phytochemical studies on four Galanthus (Amaryllidaceae) species of Turkish origin have yielded quite a number of new alkaloids with diverse structures. Among these alkaloids, gracilines and plicamines constitute two new subgroups for the Amaryllidaceae alkaloids. The gracilines contain an incorporated 10b,4a-ethanoiminodibenzo[b,d]pyrane skeleton. The plicamines are dinitrogenous compounds, where the oxygen atom in position 7 of a tazettine skeleton is replaced by a nitrogen atom substituted by a pendant 4-hydroxyphenethyl moiety. One of the new alkaloids, galanthindole, which possesses a nonfused indole ring, unlike the already known subgroups of Amaryllidaceae alkaloids, may be considered as the prototype of a third new subgroup of the Amaryllidaceae alkaloids. Additionally, two known isoquinoline alkaloids which do not possess one of the established skeletons of the Amaryllidaceae alkaloids, namely ( − )-capnoidine and (+)-bulbocapnine, have been isolated from a Turkish Galanthus species. Totally, 21 new, 20 known alkaloids and 2 known lignans have been characterized. In this review, the isolation and structure elucidation of these compounds with interesting chemical structures are described.
78 citations
TL;DR: Five new benzylphenethylamine alkaloids were isolated from Hosta plantaginea by bioassay-guided fractionation and established by means of extensive spectroscopic methods, and the relative configuration of 1 was further confirmed by single-crystal X-ray diffraction.
Abstract: Five new benzylphenethylamine alkaloids, hostasine (1), 8-demethoxyhostasine, 8-demethoxy-10-O-methylhostasine, 10-O-methylhostasirie, and 9-O-demethyl-7-O-methyllycorenine, along with 12 known compounds, were isolated from Hosta plantaginea by bioassay-guided fractionation. The structures of the new alkaloids were established by means of extensive spectroscopic methods, and the relative configuration of I was further confirmed by single-crystal X-ray diffraction. 7-Deoxy-trans-dihydronarciclasine (IC50 = 1.80 mu M), a known alkaloid, showed strong activity against tobacco mosaic virus by the half-leaf method. Some of these alkaloids were also evaluated for their inhibitory activity against acetylcholinesterase. 8-Demethoxy-10-O-methylhostasine was found to possess significant activity, with an IC50 of 2.32 mu M.
74 citations
TL;DR: The readily available and enzymatically derived cis-1,2-dihydrocatechol 4 has been elaborated, over 11 steps including an Overman rearrangement, into the non-natural enantiomer, (-)-1, of the alkaloid lycoricidine [(+)-1].
68 citations
TL;DR: The results indicate that the phenanthridone skeleton in natural Amaryllidaceae alkaloids may be a significant common element for selectivity against cancer cells; furthermore, the configuration of the methoxy-side groups is responsible for higher binding affinity to the target protein/s thus making for a more efficient anti-cancer agent.
Abstract: Pancratistatin (PST), a compound extracted from an Amaryllidaceae (AMD) family plant, has been shown to specifically induce apoptosis in cancer cells with no/minimal toxic effect on normal cells. A systematic synthetic approach has indicated that the minimum cytotoxic pharmacophore comprises the trans-fused b/c-ring system containing the 2, 3, 4-triol unit in the C-ring. To further explore the structure-activity relationship of this group of compounds we have investigated the anti-cancer efficacy and specificity of two PST-related natural compounds, AMD4 and AMD5. Both of these compounds lack the polyhydroxylated lycorane element of PST instead having a methoxy-substuituted crinane skeleton. Our results indicate that AMD5 has efficacy and selectivity similar to PST, albeit at a 10-fold increased concentration. Interestingly AMD4 lacks apoptotic activity. Our results indicate that the phenanthridone skeleton in natural Amaryllidaceae alkaloids may be a significant common element for selectivity against cancer cells; furthermore, the configuration of the methoxy-side groups is responsible for higher binding affinity to the target protein/s thus making for a more efficient anti-cancer agent.
57 citations
TL;DR: The synthesis of a chemical compound library using diversity-oriented synthesis (DOS) is discussed in this paper, which is structurally inspired by the Amaryllidaceae alkaloids, a family of natural products which has been known to demonstrate potent antiviral and antineoplastic activity.
6 citations
TL;DR: In this article, a general strategy for synthesizing crinine-type Amaryllidaceae alkaloids was developed, and total synthesization of four representative crinines-type amaryllids was accomplished via a common intermediate 17.
Abstract: A general strategy for synthesizing the crinine-type Amaryllidaceae alkaloids was developed. And total syntheses of four representative crinine-type Amaryllidaceae alkaloids: (±)-haemanthidine, (±)-pretazettine, (±)-tazettine, and (±)-crinamine, were accomplished via a common intermediate 17. This crucial precursor was achieved on the basis of the NBS-promoted semipinacol rearrangement recently developed by our group and an intramolecular Michael addition, which efficiently constructed the sterically congested quaternary carbon center and the hydroindole skeleton of the crinine-type alkaloids, respectively.
3 citations
TL;DR: In this paper, the synthesis of functionalized dihydroisoquinolin-5(6H)-one core, which is the bottom part of the structure of alkaloids isolated from this botanic family, is described, using Morita-Baylis-Hillman adducts as substrate.
Abstract: We disclose herein our results concerning a study aiming at the synthesis of the highly substituted carbon skeleton of alkaloids isolated from plants of the Amaryllidaceae family. The total synthesis of the functionalized dihydroisoquinolin-5(6H)-one core, which is the bottom part of the structure of alkaloids isolated from this botanic family, is described, using Morita-Baylis-Hillman adducts as substrate. This compound should be a useful and valuable intermediate for the total synthesis of alkaloids isolated from Amaryllidaceae.
2 citations
TL;DR: In this paper, a series of regioselectively functionalized benzo[c]chromen-6-ones, phenanthridinones, andphenanthridine derivatives have been prepared by an anionic cyclization and in situ oxidation sequence starting from 2-bromobenzyl-2-fluorophenyl ethers and amines.
Abstract: A series of regioselectively functionalized benzo[c]chromen-6-ones, phenanthridinones, and phenanthridine derivatives have been prepared by an anionic cyclization and in situ oxidation sequence starting from 2-bromobenzyl-2-fluorophenyl ethers and amines. These processes involve the generation of a benzyne-tethered aryllithium intermediate and subsequent 6-exo-dig cyclization. By applying this methodology to the appropriate starting materials, short and efficient syntheses of Amaryllidaceae alkaloids trisphaeridine and N-methylcrinasiadine have been achieved in good overall yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
1 citations