Zur kenntnis der rubromycine

Brockmann, Hans; Lenk, Werner; Schwantje, Gerd; Zeeck, Axel

doi:10.1016/s0040-4039(01)82822-7

Cited by 47 publications

(23 citation statements)

References 7 publications

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“…The evaluation of the 13 C-NMR spectrum indicated that [1,[3][4][5][6][7][8][9][10][11][12][13] C 2 ]acetoacetic acid was not incorporated into 6. Currently, this negative result does not allow to differentiate between the mentioned alternatives.…”

Section: Biosynthesismentioning

confidence: 99%

Structural and Biosynthetic Investigations of the Rubromycins

et al. 2000

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The structure of the known secondary metabolite β‐rubromycin was corrected, based on spectroscopic and chemical investigations, from o‐quinone 1 to p‐quinone 6. By feeding [U‐13C3]malonic acid to the rubromycin‐producing strain, Streptomyces sp. A1, the polyketide origin of the skeleton was verified, but the identity of the starter unit and the folding mechanism of the polyketide chain are still unclear. From the culture broth of the strain A1, in addition to 6, the co‐metabolites γ‐rubromycin (3), δ‐rubromycin (4) and 3′‐hydroxy‐β‐rubromycin (7) were isolated. Their structures were determined or confirmed by detailed spectroscopic analysis. The rubromycins inhibit HIV‐1 reverse transcriptase (RT) and are cytostatically active against different tumor cell lines.

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Section: Biosynthesismentioning

confidence: 99%

Structural and Biosynthetic Investigations of the Rubromycins

et al. 2000

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“…g-Rubromycin [1] (1, Scheme 1), the prototypical member of a structurally related family of antibiotics known as the rubromycins, consists of a densely oxygenated naphthazarin ring and an isocoumarin moiety linked through a unique aromatic 5,6-spiroketal ring system (Scheme 1). The rubromycins exhibit a wide range of biological activity including antimicrobial and anticancer properties.…”

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confidence: 99%

An Efficient Formal Synthesis of the Human Telomerase Inhibitor (±)‐γ‐Rubromycin

et al. 2009

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Balancing act: The correct balance of electronic factors in the naphthazarin and isocoumarin fragments facilitates the acid‐mediated spiroketalization step to afford the key densely functionalized spiroketal (see picture; EOM=ethoxymethyl) in the formal synthesis of (±)‐γ‐rubromycin. A novel regioselective allyloxylation/Claisen rearrangement of 2‐azido‐1,4‐naphthoquinone provides access to the highly oxygenated naphthazarin fragment.

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“…[15] 4-Substituted chroman-2-ol 5 is a synthetically valuable intermediate that can be easily converted into chromans and their derivatives with antimicrobial and anticancer properties. [16] Good to excellent yields (up to 96 %) were achieved for products 3c-f, 3h-i, 3m, and 5 ( Table 1). The lower yields of 3j-l (31-37 %) were caused by the low conversion rates with nitrostyrene derivatives 2j-l and the non-enzymatic hydration of 2j-l in aqueous reaction media.…”

Section: Resultsmentioning

confidence: 90%

Stereochemical Control of Enzymatic Carbon–Carbon Bond‐Forming Michael‐Type Additions by “Substrate Engineering”

et al. 2016

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The enzyme 4‐oxalocrotonate tautomerase (4‐OT) promiscuously catalyzes the Michael‐type addition of acetaldehyde to β‐nitrostyrene derivatives to yield chiral γ‐nitroaldehydes, which are important precursors for pharmaceutically active γ‐aminobutyric acids. In this study, we investigated the effect of different substituents at the aromatic ring of the Michael acceptor on the catalytic efficiency and stereoselectivity of the 4‐OT‐catalyzed acetaldehyde addition reactions. Highly enantioenriched (R)‐ and (S)‐γ‐nitroaldehydes and 4‐substituted chroman‐2‐ol could be obtained in good to excellent yields by applying different substituents at appropriate positions of the aromatic substrate. Stereochemical control of these enzymatic Michael‐type additions by “substrate engineering” allowed the enantioselective synthesis of valuable γ‐aminobutyric acid precursors. In addition, the results suggest a novel enzymatic synthesis route towards precursors for chromans and derivatives, which are valuable scaffolds for preparing biologically active natural products.

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Zur kenntnis der rubromycine

Cited by 47 publications

References 7 publications

Structural and Biosynthetic Investigations of the Rubromycins

Structural and Biosynthetic Investigations of the Rubromycins

An Efficient Formal Synthesis of the Human Telomerase Inhibitor (±)‐γ‐Rubromycin

Stereochemical Control of Enzymatic Carbon–Carbon Bond‐Forming Michael‐Type Additions by “Substrate Engineering”

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