DDQ oxidations in the indole area. Synthesis of 4-alkoxy-.beta.-carbolines including the natural products crenatine and 1-methoxycanthin-6-one

Hagen, Timothy J.; Narayanan, K.; Names, Jeffrey; Cook, James M.

doi:10.1021/jo00270a029

Cited by 67 publications

(32 citation statements)

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“…The tryptophan side chain is subject to oxidation at the β position with DDQ (24). In order to reveal efficiently all the latent Trp subunits, Dht must be oxidized selectively in the presence of other tryptophans.…”

Section: Resultsmentioning

confidence: 99%

Control of ditryptophan cross‐linking: dihydrotryptophan as a tryptophan precursor in peptide synthesis

Dinh

Vranken

1999

The Journal of Peptide Research

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In neat trifluoroacetic acid, tryptophan side chains cross-link to form a diastereomeric mixture of tryptophan dimers. Convergent oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) converts tryptophan dimers to ditryptophan. Since cross-link formation is under thermodynamic control, there has been no simple way of controlling the regiochemistry of the cross-linking process when more than one tryptophan side chain is present. Here, we show that dihydrotryptophan (Dht) can be incorporated into peptides as a tryptophan precursor, which reforms tryptophan upon treatment with DDQ. Dihydrotryptophan was prepared as a mixture of gammaS and gammaR diastereomers and the indoline nitrogen was protected with a Cbz group. The resulting amino acid, Nalpha-BOC-Dht(Cbz)-OH, was then incorporated into peptides as a mixture of diastereomers. Dht was resistant to tryptophan cross-linking in neat trifluoroacetic acid and was converted back to tryptophan during convergent oxidation of tryptophan dimers. While Dht is useful for control of ditryptophan regiochemistry and as a potential tryptophan analog, it is not a general strategy for Trp protection since DDQ is unlikely to be compatible with easily oxidized amino acids such as cysteine.

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Section: Resultsmentioning

confidence: 99%

Control of ditryptophan cross‐linking: dihydrotryptophan as a tryptophan precursor in peptide synthesis

Dinh

Vranken

1999

The Journal of Peptide Research

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“…The canthin-6-one alkaloids have been synthesized via different approaches by many researchers [2,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75]. In order to use these methods to guide our review more clearly, we categorized classic and efficient synthetic methods according to their key reaction steps.…”

Section: Chemistrymentioning

confidence: 99%

Fruitful Decades for Canthin-6-ones from 1952 to 2015: Biosynthesis, Chemistry, and Biological Activities

Dai

Wang

et al. 2016

Molecules

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Abstract:In this review, more than 60 natural canthin-6-one alkaloids and their structures are considered. The biosynthesis, efficient and classic synthetic approaches, and biological activities of canthin-6-one alkaloids, from 1952 to 2015, are discussed. From an analysis of their structural properties and an investigation of the literature, possible future trends for canthin-6-one alkaloids are proposed. The information reported will be helpful in future research on canthin-6-one alkaloids.

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“…We accomplished the total synthesis of MVC (29a) in addition to several related β-carbolines using Cook's procedure for the synthesis of crenatine, a structurally related alkaloid, with some modifications [43][44][45] (Chart 3). The preparation of the β-carbolinium salts 30, which corresponded to the DLCs, was achieved by a simple quaternization with the alkyl tosylate or alkyl halide.…”

Section: )mentioning

confidence: 99%

π-Delocalized Lipophilic Cations as New Candidates for Antimalarial, Antitrypanosomal and Antileishmanial Agents: Synthesis, Evaluation of Antiprotozoal Potency, and Insight into Their Action Mechanisms

Takasu

2016

CHEMICAL & PHARMACEUTICAL BULLETIN

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The search for new drugs that could treat tropical protozoan diseases, such as malaria or neglected tropical diseases (NTDs), motivates many medicinal chemists. New classes of antiprotozoal drugs that act through a novel mechanism of action must be developed. This review presents our efforts toward finding new candidate treatments for malaria, American trypanosomiasis, human African trypanosomiasis and leishmaniasis based on π-delocalized lipophilic cations (DLCs). DLCs, such as rhodacyanines, azarhodacyanines, β-carbolinium salts, and phenoxazinium salts, displayed strong antiprotozoal activities with highly selective indices. Several DLCs displayed moderate to excellent in vivo efficacies against Plasmodium berghei when administered intraperitoneally or orally. This review also discusses chemical biology approaches to understanding the mechanism of action underlying the antimalarial rhodacyanines.

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DDQ oxidations in the indole area. Synthesis of 4-alkoxy-.beta.-carbolines including the natural products crenatine and 1-methoxycanthin-6-one

Cited by 67 publications

References 0 publications

Control of ditryptophan cross‐linking: dihydrotryptophan as a tryptophan precursor in peptide synthesis

Control of ditryptophan cross‐linking: dihydrotryptophan as a tryptophan precursor in peptide synthesis

Fruitful Decades for Canthin-6-ones from 1952 to 2015: Biosynthesis, Chemistry, and Biological Activities

π-Delocalized Lipophilic Cations as New Candidates for Antimalarial, Antitrypanosomal and Antileishmanial Agents: Synthesis, Evaluation of Antiprotozoal Potency, and Insight into Their Action Mechanisms

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