Chemistry of four-membered cyclic nitrones. 4. Reaction with electrophilic reagents and conversion into .beta.-lactam derivatives

Pennings, Marcel L. M.; Reinhoudt, David N.; Harkema, Sybolt; Hummel, G.J. van

doi:10.1021/jo00152a015

Cited by 28 publications

(10 citation statements)

References 2 publications

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“…The uncertainty in the planar structure of 1 due to the invisibility of the N -OH and carboxylic OH moieties in the 1 H NMR spectrum was further clarified by utilizing chemical reactions and NMR spectroscopic analyses of the products. To confirm the presence of two N -OH groups, the N -OHs were converted to NHs using TiCl 3 (Pennings et al, 1983 ). The structure of the reduction product (2- N ,16- N -deoxydentigerumycin E, 2 ) (Figure 2 ) was elucidated based on the 1 H NMR, COSY, HMBC, HSQC, TOCSY, and ROESY spectra (Table S1 , Figures S11 – S16 ) and HRMS data, confirming the presence of the N -OH groups of N -OH-Thr and N -OH-Gly in dentigerumycin E ( 1 ).…”

Section: Resultsmentioning

confidence: 99%

Coculture of Marine Streptomyces sp. With Bacillus sp. Produces a New Piperazic Acid-Bearing Cyclic Peptide

et al. 2018

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Microbial culture conditions in the laboratory, which conventionally involve the cultivation of one strain in one culture vessel, are vastly different from natural microbial environments. Even though perfectly mimicking natural microbial interactions is virtually impossible, the cocultivation of multiple microbial strains is a reasonable strategy to induce the production of secondary metabolites, which enables the discovery of new bioactive natural products. Our coculture of marine Streptomyces and Bacillus strains isolated together from an intertidal mudflat led to discover a new metabolite, dentigerumycin E (1). Dentigerumycin E was determined to be a new cyclic hexapeptide incorporating three piperazic acids, N-OH-Thr, N-OH-Gly, β-OH-Leu, and a pyran-bearing polyketide acyl chain mainly by analysis of its NMR and MS spectroscopic data. The putative PKS-NRPS biosynthetic gene cluster for dentigerumycin E was found in the Streptomyces strain, providing clear evidence that this cyclic peptide is produced by the Streptomyces strain. The absolute configuration of dentigerumycin E was established based on the advanced Marfey's method, ROESY NMR correlations, and analysis of the amino acid sequence of the ketoreductase domain in the biosynthetic gene cluster. In biological evaluation of dentigerumycin E (1) and its chemical derivatives [2-N,16-N-deoxydenteigerumycin E (2) and dentigerumycin methyl ester (3)], only dentigerumycin E exhibited antiproliferative and antimetastatic activities against human cancer cells, indicating that N-OH and carboxylic acid functional groups are essential for the biological activity.

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Section: Resultsmentioning

confidence: 99%

Coculture of Marine Streptomyces sp. With Bacillus sp. Produces a New Piperazic Acid-Bearing Cyclic Peptide

et al. 2018

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“…Since free N -OH-Ala was not expected to react with FDLA, we converted the N -OH to N -H by treatment of dentigerumycin with TiCl 3 (see Supplementary Methods online) 14. We confirmed this conversion by 1 H, gCOSY, TOCSY, gHSQC, and gHMBC NMR (Supplementary Fig 3 online) of the reduction product ( 8 ) and high resolution mass spectral analysis (Supplementary Table 2 online).…”

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confidence: 79%

Dentigerumycin: a bacterial mediator of an ant-fungus symbiosis

et al. 2009

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Fungus-growing ants engage in mutualistic associations with both the fungus they cultivate for food and actinobacteria (Pseudonocardia spp.) that produce selective antibiotics to defend that fungus from specialized fungal parasites. In the first system to be analyzed at the molecular level, the bacterium associated with the ant Apterostigma dentigerum produces dentigerumycin, a cyclic depsipeptide with highly modified amino acids, to selectively inhibit the parasitic fungus (Escovopsis sp.).

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“…Because aziridine ring can be regarded as a stepping stone towards a wide variety of amines via well documented ring‐opening chemistry,16 these unprotected building blocks provide a solution to broad challenges faced by protected amino aldehydes17 in complex amine transformations. Interestingly, the only prior mentioning of unprotected aziridine aldehydes was in the work by Rheinhoudt, who isolated a monomeric aziridine–aldehyde species as an unstable by‐product that decomposed during purification 18…”

Section: Discussionmentioning

confidence: 99%

Overcoming the Demons of Protecting Groups with Amphoteric Molecules

Yudin

Hili

2007

Chemistry A European J

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Synthetic organic chemists have long depended on protecting group manipulations when faced with the challenges of chemoselectivity and functional group incompatibility. Overcoming this dependence will improve the overall efficiency of chemical synthesis. By taking advantage of orthogonally reactive functional groups, amphoteric molecules can afford access not only to more efficient and strategic syntheses but also to the development of novel chemical transformations.

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Chemistry of four-membered cyclic nitrones. 4. Reaction with electrophilic reagents and conversion into .beta.-lactam derivatives

Cited by 28 publications

References 2 publications

Coculture of Marine Streptomyces sp. With Bacillus sp. Produces a New Piperazic Acid-Bearing Cyclic Peptide

Coculture of Marine Streptomyces sp. With Bacillus sp. Produces a New Piperazic Acid-Bearing Cyclic Peptide

Dentigerumycin: a bacterial mediator of an ant-fungus symbiosis

Overcoming the Demons of Protecting Groups with Amphoteric Molecules

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