Two Alangium Alkaloids from Alangium lamarckii

Itoh, Atsuko; Ikuta, Yuki; Tanahashi, Takao; Nagakura, Naotaka

doi:10.1021/np0000163

Cited by 48 publications

(23 citation statements)

References 16 publications

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“…Nowadays, emetine (1) is not used as a drug anymore due to its considerable toxicity. Tubulosine (2) was isolated from the dried fruits of Alangium lamarckii [4] and the sap of Pogonopus speciosus. [5] It is remarkably active against several cancer cell lines [5,6] and has been studied for various other biological activities, such as inhibition of protein biosynthesis [7] and HIV reverse transcriptase inhibitory activities.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective Total Syntheses of the Ipecacuanha Alkaloid Emetine, the Alangium Alkaloid Tubulosine and a Novel Benzoquinolizidine Alkaloid by Using a Domino Process

Tietze

Rackelmann

Müller

2004

Chemistry A European J

111

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The first enantioselective syntheses of the Ipecacuanha alkaloid emetine (1) and the Alangium alkaloid tubulosine (2) is described employing a domino Knoevenagel/hetero-Diels-Alder reaction and an enantioselective catalytic transfer hydrogenation of imines as key steps. Thus, hydrogenation of the imine 15 with the catalyst (R,R)-16 gives the tetrahydroisoquinoline 14 with 95 % ee which was transformed into the aldehyde (1S)-7. The three-component domino reaction of (1S)-7 with 6 and 8 led to 19, which in a second domino process was treated with K(2)CO(3) in methanol followed by a hydrogenation to give the benzoquinolizidine 4 together with the diastereomers 22 and 23 in a overall yield of 66 %. Further transformation of 4 with the amines 3 and 5 yielded enantiopure emetine (1) and tubulosine (2), respectively. In addition, starting from 19 the novel benzoquinolizidine alkaloid 34 was synthesised; this compound resembles the vallesiachotamine alkaloid dihydroantirhin 31, which has not been isolated so far but probably must also exist in nature.

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Section: Introductionmentioning

confidence: 99%

Enantioselective Total Syntheses of the Ipecacuanha Alkaloid Emetine, the Alangium Alkaloid Tubulosine and a Novel Benzoquinolizidine Alkaloid by Using a Domino Process

Tietze

Rackelmann

Müller

2004

Chemistry A European J

111

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“…The synthesis of emetine 11 [12] and tubulosine 12 [13] was also solved with the same synthetic strategy starting from the optically active tetrahydroisoquinoline derivative 22 (Scheme 4). Without the isolation of the resulting lactone 24, it was treated with potassium carbonate, methanol, and a catalytic amount of palladium on charcoal, first under a nitrogen atmosphere and then under hydrogen atmosphere to give the desired benzoquinolizidine 25 together with its diastereomers.…”

Section: Diversity-oriented Alkaloid Synthesismentioning

confidence: 99%

Meldrum's Acid in Multicomponent Reactions: Applications to Combinatorial and Diversity‐Oriented Synthesis

Gerencsér¹,

Dormán²,

Darvas³

2006

QSAR Comb. Sci.

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In a multicomponent reaction (MCR), one can create multiple new bonds in a single reaction from readily available starting materials; thus, MCRs are resource-and timeeffective and therefore economically favorable processes in diversity generation. In contrast, there are MCRs where a multifunctional building block is introduced instead of an additional diversity-holding component, and these can be derivatized using very diverse reactions post-synthetically leading to novel chemotypes. The synthetic applications of Meldrums acid are focusing primarily on reactions where it is applied as an alternative for acyclic malonic esters. However, its highly acidic character broadened its applications and made it a very useful reagent for MCRs or more precisely in tandem or domino reactions. There are numerous examples reported for the use of the alkylidene conjugates of Meldrums acid as dienophiles in hetero-Diels -Alder reactions, as well as Michael acceptors. In most cases spontaneous or concomitant post-synthetic derivatization increased its synthetic utility. This minireview gives a non-exhaustive insight into MCRs involving Meldrums acid, describing various applications in combinatorial and diversityoriented synthesis.

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“…The described approach also allows simple access to indole alkaloids of the vallesiachotamine type which in nature are formed by condensation of N4 with C17 in Another class of alkaloids that has recently be synthesized using a three component domino-Knoevenagel-hetero-Diels-Alder reaction (Scheme 5.26) are the ipecacuanha alkaloids such as emetine 111 [40] and the alangium alkaloids such as tubulosine 112 [41], which both belong to the group of tetrahydroisoquinoline alkaloids and are formed in nature from dopamine and the monoterpene secologanin. Emetine 111 was isolated from Radix ipecacuanha and the roots of Psychotria ipecacuanha and Cephalis acuminata and possesses manifold interesting biological activities [42].…”

Section: Three-and Four-component-domino-knoevenagel-hetero-diels-aldmentioning

confidence: 99%

The Domino‐Knoevenagel‐Hetero‐Diels–Alder Reaction and Related Transformations

Tietze

Rackelmann

2005

Multicomponent Reactions

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Two Alangium Alkaloids from Alangium lamarckii

Cited by 48 publications

References 16 publications

Enantioselective Total Syntheses of the Ipecacuanha Alkaloid Emetine, the Alangium Alkaloid Tubulosine and a Novel Benzoquinolizidine Alkaloid by Using a Domino Process

Enantioselective Total Syntheses of the Ipecacuanha Alkaloid Emetine, the Alangium Alkaloid Tubulosine and a Novel Benzoquinolizidine Alkaloid by Using a Domino Process

Meldrum's Acid in Multicomponent Reactions: Applications to Combinatorial and Diversity‐Oriented Synthesis

The Domino‐Knoevenagel‐Hetero‐Diels–Alder Reaction and Related Transformations

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