Studies directed toward the synthesis of vancomycin and related cyclic peptides

Rao, A. V. Rama; Gurjar, Mukund K.; Reddy, K. Laxma; Rao, A. S.

doi:10.1021/cr00038a014

Cited by 245 publications

(74 citation statements)

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“…[24] However, the synthesis of this class of molecules currently relies on classical Ullmann condensation reactions between aryl halides and phenols. [25] This problem was addressed by Evans and co-workers, who further expanded the scope of these transformations whilst investigating the coupling of functionalized phenolic tyrosine derivatives 1-3 (Scheme 2, Table 3). In these reactions pyridine (2.0 equiv) was used as the base (in place of Et 3 N) to afford the desired diaryl ethers 4-6, respectively, in good to excellent yields with no apparent change in the integrity of the racemization-prone stereogenic centers.…”

Section: Substrate Scopementioning

confidence: 99%

Modern Synthetic Methods for Copper‐Mediated C(aryl)O, C(aryl)N, and C(aryl)S Bond Formation

Ley,

Thomas

2003

Angew Chem Int Ed

2,497

816

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The copper-mediated C(aryl)[bond]N, C(aryl)[bond]O, and C(aryl)[bond]S bond formation is an important transformation and has been developed to include a wide range of substrates. This Review highlights the recent developments in the copper-mediated (both stoichiometric and catalytic) reactions of aryl boronic acids, aryl halides, iodonium salts, siloxanes, stannanes, plumbanes, bismuthates, and trifluoroborate salts as aryl donors. In particular, the recent introduction of boronic acids as reaction partners in both O- and N-arylation has been a significant discovery and will occupy centre-stage in this review. Clear improvements can be obtained by the correct choice of copper source, base, ligands, and other additives. Mechanistic investigations should provide insight into the catalytically active species, which would aid in the development of milder, more-efficient methods.

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Section: Substrate Scopementioning

confidence: 99%

Modern Synthetic Methods for Copper‐Mediated C(aryl)O, C(aryl)N, and C(aryl)S Bond Formation

Ley,

Thomas

2003

Angew Chem Int Ed

2,497

816

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“…Additionally, we monitor time-course changes in the gut microbiota community during the course of the recovery using 16S rRNA gene polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) analysis. For this, we have used vancomycin (a glycopeptide antibiotic, 22 with broad activity against Gram-positive bacteria), which causes marked decrease in gut microbiotal populations in mice. 23 Vancomycin was chosen as a means of reducing the Gram-positive bacteria in the gut without overtly modifying the Gram-negative microbes, in order to target one particular aspect of the microbial influence on host metabolism.…”

Section: Introductionmentioning

confidence: 99%

Metabonomic and Microbiological Analysis of the Dynamic Effect of Vancomycin-Induced Gut Microbiota Modification in the Mouse

et al. 2008

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The effects of the antibiotic vancomycin (2 × 100 mg/kg/day) on the gut microbiota of female mice (outbred NMRI strain) were studied, in order to assess the relative contribution of the gut microbiome to host metabolism. The host's metabolic phenotype was characterized using 1 H NMR spectroscopy of urine and fecal extract samples. Time-course changes in the gut microbiotal community after administration of vancomycin were monitored using 16S rRNA gene PCR and denaturing gradient gel electrophoresis (PCR-DGGE) analysis and showed a strong effect on several species, mostly within the Firmicutes. Vancomycin treatment was associated with fecal excretion of uracil, amino acids and short chain fatty acids (SCFAs), highlighting the contribution of the gut microbiota to the production and metabolism of these dietary compounds. Clear differences in gut microbial communities between control and antibiotic-treated mice were observed in the current study. Reduced urinary excretion of gut microbial co-metabolites phenylacetylglycine and hippurate was also observed. Regression of urinary hippurate and phenylacetylglycine concentrations against the fecal metabolite profile showed a strong association between these urinary metabolites and a wide range of fecal metabolites, including amino acids and SCFAs. Fecal choline was inversely correlated with urinary hippurate. Metabolic profiling, coupled with the metagenomic study of this antibiotic model, illustrates the close inter-relationship between the host and microbial "metabotypes", and will provide a basis for further experiments probing the understanding of the microbial-mammalian metabolic axis.

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“…[337][338][339][340][341] Lactam formation is normally achieved under high dilution using syringe-pump techniques to minimize competing oligomerization pathways, or via side-chain attachment of the cyclization substrate onto a polymer support to achieve 'pseudodilution' conditions. Cyclization of larger peptides (47 amino acids) generally proceeds in good yields, however, smaller cyclic peptides (o7 amino acids) are normally more difficult to prepare, with cyclization success highly dependent on the nature of their component α-amino acids.…”

Section: Phmentioning

confidence: 99%