Relative configuration of the alkaloid augustamine

Ali, Adel A.; Hambloch, H.; Frahm, A. W.

doi:10.1016/s0031-9422(00)80106-5

Cited by 23 publications

(8 citation statements)

References 2 publications

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“…Augustamine ( 2 ) has an octahydroindole core similar to that of amabiline. Augustamine was isolated from Crinum augustum in 1981 and characterized in 1983, and interest in its pharmacological properties persists . Its absolute configuration was not assigned.…”

Section: Syntheses Of (−)-Amabiline and (−)-Augustaminementioning

confidence: 99%

Assembly of 3a-Arylperhydroindoles by the Intramolecular Cycloaddition of 2-Azaallyl Anions with Alkenes. Total Syntheses of (±)-Crinine, (±)-6-Epicrinine, (−)-Amabiline, and (−)-Augustamine

Pearson

Lovering

1998

J. Org. Chem.

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The 2-azaallyl anion route to pyrrolidines was used for the concise synthesis of alkaloids featuring the 3a-arylperhydroindole nucleus. The brevity and efficiency of the syntheses described are particularly notable. The key transformations involved the tin−lithium exchange of (2-azaallyl)stannanes to 2-azaallyl anions, which participated in intramolecular [π4s + π2s] cycloadditions with styrenes to produce the requisite 3a-arylperhydroindoles. (±)-Crinine was synthesized in eight steps in 20% overall yield, with the key cycloaddition producing a single stereoisomer of the perhydroindole in 80% yield. (±)-6-Epicrinine was an intermediate in this synthesis. The key cycloaddition involved the use of a diene as the anionophile. The first asymmetric syntheses of (−)-amabiline and (−)-augustamine were accomplished in overall yields of 43% (in eight steps) and 42% (in nine steps), respectively, confirming or determining the absolute stereochemistry of the natural products. The key cycloadditions produced the perhydroindoles in 83% and 74% yields, respectively, with reasonable stereocontrol. The highly stereoselective cycloaddition leading to a trans-dialkoxyperhydroindole in 75% yield was consistent with stereochemical predictions. These studies contribute to a growing body of knowledge on the scope and stereochemistry of 2-azaallyl anion cycloadditions.

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Section: Syntheses Of (−)-Amabiline and (−)-Augustaminementioning

confidence: 99%

Assembly of 3a-Arylperhydroindoles by the Intramolecular Cycloaddition of 2-Azaallyl Anions with Alkenes. Total Syntheses of (±)-Crinine, (±)-6-Epicrinine, (−)-Amabiline, and (−)-Augustamine

Pearson

Lovering

1998

J. Org. Chem.

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“…We consequently decided to verify in vitro the activity of six alkaloids isolated from C. amabile , augustamine ( 22 ), augustine ( 13 ), augustine N -oxide ( 1 ), buphanisine ( 8 ), buphanisine N -oxide ( 2 ) and crinine ( 10 ), against four different protozoa, Trypanosoma brucei rhodesiense , Trypanosoma cruzi , Leishmania donovani and Plasmodium falciparum , which are related to sleeping sickness, Chagas disease, visceral leishmaniasis and malaria, respectively. These alkaloids are structurally very similar, with the exception of augustamine, which is a unique kind of Amaryllidaceae alkaloid previously isolated from other Crinum species, including C. augustum , C. kirkii and C. latifolium [ 28 , 31 , 32 ], and completely elucidated in 2000 [ 33 ]. The rareness of this structure motivated us to isolate it and check its biological activity.…”

Section: Resultsmentioning

confidence: 99%

N-oxide alkaloids from Crinum amabile (Amaryllidaceae)

et al. 2018

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Natural products play an important role in the development of new drugs. In this context, the Amaryllidaceae alkaloids have attracted considerable attention in view of their unique structural features and various biological activities. In this study, twenty-three alkaloids were identified from Crinum amabile by GC-MS and two new structures (augustine N-oxide and buphanisine N-oxide) were structurally elucidated by NMR. Anti-parasitic and cholinesterase (AChE and BuChE) inhibitory activities of six alkaloids isolated from this species, including the two new compounds, are described herein. None of the alkaloids isolated from C. amabile gave better results than the reference drugs, so it was possible to conclude that the N-oxide group does not increase their therapeutic potential.

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“…(synonym Crinum x amabile Donn ex Ker Gawl.) [48], a preliminary screen showed it to be inactive against Molt4 T-lymphoma cells [52]. More recently, interest in the cytotoxic properties of these compounds has been rekindled [50,51].…”

Section: The Augustamine Groupmentioning

confidence: 99%

“…[40]. The first part of the study involved the isolation of 7 alkaloids, including the 2 montanine analogs nangustine (48) and pancracine (49) [40]. Normal L6 mouse myoblasts were utilized in the second aspect of the study to measure the cytotoxicities of the isolated compounds [40].…”

Section: The Montanine Groupmentioning

confidence: 99%

Cytotoxic Agents in the Minor Alkaloid Groups of the Amaryllidaceae

Nair

Staden

2021

Planta Med

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Over 600 alkaloids have to date been identified in the plant family Amaryllidaceae. These have been arranged into as many as 15 different groups based on their characteristic structural features. The vast majority of studies on the biological properties of Amaryllidaceae alkaloids have probed their anticancer potential. While most efforts have focused on the major alkaloid groups, the volume and diversity afforded by the minor alkaloid groups have promoted their usefulness as targets for cancer cell line screening purposes. This survey is an in-depth review of such activities described for around 90 representatives from 10 minor alkaloid groups of the Amaryllidaceae. These have been evaluated against over 60 cell lines categorized into 18 different types of cancer. The montanine and cripowellin groups were identified as the most potent, with some in the latter demonstrating low nanomolar level antiproliferative activities. Despite their challenging molecular architectures, the minor alkaloid groups have allowed for facile adjustments to be made to their structures, thereby altering the size, geometry, and electronics of the targets available for structure-activity relationship studies. Nevertheless, it was seen with a regular frequency that the parent alkaloids were better cytotoxic agents than the corresponding semisynthetic derivatives. There has also been significant interest in how the minor alkaloid groups manifest their effects in cancer cells. Among the various targets and pathways in which they were seen to mediate, their ability to induce apoptosis in cancer cells is most appealing.

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Relative configuration of the alkaloid augustamine

Cited by 23 publications

References 2 publications

Assembly of 3a-Arylperhydroindoles by the Intramolecular Cycloaddition of 2-Azaallyl Anions with Alkenes. Total Syntheses of (±)-Crinine, (±)-6-Epicrinine, (−)-Amabiline, and (−)-Augustamine

Assembly of 3a-Arylperhydroindoles by the Intramolecular Cycloaddition of 2-Azaallyl Anions with Alkenes. Total Syntheses of (±)-Crinine, (±)-6-Epicrinine, (−)-Amabiline, and (−)-Augustamine

N-oxide alkaloids from Crinum amabile (Amaryllidaceae)

Cytotoxic Agents in the Minor Alkaloid Groups of the Amaryllidaceae

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