PubMed Health⌕ Search

Biomedical subjects

Jefferson D Revell

Publications and source records attributed to Jefferson D Revell.

7 recordsLinked to original sources
PubMed2006

Peptide-polyethylene glycol conjugates: synthesis and properties of peptides bearing a C-terminal polyethylene glycol chain.

The introduction of a polyethylene glycol chain has become a popular tool for increasing water solubility and bioavailability. Our interest in the development of catalytically active peptides and the selective recognition of peptides has led us to investigate strategies to increase the solubility of peptides in organic solvents. Specifically, we became interested in the introduction of solubilizing moieties at the C-terminus of two peptides. Here we present different synthetic strategies for the preparation of peptide-polyethylene glycol conjugates and discuss the effect of the polyethylene glycol chain on the solubility and other properties, such as the catalytic activity of these peptides.

Catalysis↗
PubMed2006

Solid-supported and pegylated H-Pro-Pro-Asp-NHR as catalysts for asymmetric aldol reactions.

H-Pro-Pro-Asp-NH2 is a highly active and selective catalyst for asymmetric aldol reactions. Here, the versatility of H-Pro-Pro-Asp-NH2 has been further improved by immobilization on a solid support and functionalization with a short polyethylene glycol linker at the C-terminus. The development, synthesis, and the catalytic properties in aldol reactions of H-Pro-Pro-Asp-resin and H-Pro-Pro-Asp-Ahx-NH(CH2CH2O)3CH3 are described. For the solid-supported catalyst, TentaGel with a loading of 0.1-0.2 mmol g(-1) proved to be the optimal support. The solid-supported catalyst can be recycled at least three times without a significant drop in the catalytic activity or selectivity. Using the pegylated catalyst H-Pro-Pro-Asp-Ahx-NH(CH2CH2O)3CH3, only 0.5 mol % are necessary to obtain aldol products in up to 96% yield and 91% enantiomeric excess. In all cases, enantioselectivities are comparable to those obtained with the parent catalyst H-Pro-Pro-Asp-NH2. Thus, immobilization of H-Pro-Pro-Asp-NH2 on Tentagel as well as pegylation led to catalysts with selectivities comparable to the nonmodified catalyst, exhibiting additional distinct advantages such as facile reusability, ease of handling, higher solubility, and thereby greater versatility. handling, higher solubility, and thereby greater versatility.

Acrylic Resins↗
PubMed2005

Increased structural complexity leads to higher activity: peptides as efficient and versatile catalysts for asymmetric aldol reactions.

[reaction: see text] Peptides containing a secondary amine and a carboxylic acid in a specific orientation to each other are presented as highly efficient catalysts for asymmetric aldol reactions: (1) their activity is considerably higher compared to that of proline, and (2) the enantioselectivity of the peptidic catalysts can be changed from (R)- to (S)-selectivity by simple modifications of the secondary structure.

Aldehydes↗
PubMed2005

PS-COD and PS-9-BBN: polymer-supported reagents for solution-phase parallel synthesis.

1,5-Cyclooctadiene was deprotonated under LICKOR conditions and reacted with Merrifield resin to afford an immobilized cyclooctadiene in high yield. This polymer is effective as a halogen scavenger, while hydroboration leads to a supported 9-BBN analogue. The latter exhibits similar regioselectivity to 9-BBN in olefin hydroboration. [reaction: see text]

Alkenes↗
PubMed2002

Ionic liquid acceleration of solid-phase suzuki-miyaura cross-coupling reactions.

[reaction: see text] Room-temperature ionic liquids promote various transition metal-catalyzed reactions in the solution phase. Here, for the first time, we show that these effects are translatable to solid-phase reactions. The Suzuki-Miyaura cross-coupling of 4-iodophenol immobilized on polystyrene-Wang resin with various arylboronic acids was significantly accelerated by the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)(-)]).

Borates↗
PubMed2002

Synthesis of functionalized 1,5-cyclooctadienes by LICKOR metalation.

1,5-Cyclooctadiene was lithiated under LICKOR superbase conditions followed by reaction with alkyl halides or ethylene oxide to yield 3-substituted 1,5-cyclooctadienes in high yield and purity. This procedure is suitable for preparation of 1,5-cyclooctadienes carrying pendant functional groups for immobilization on solid-phase resins.

Journal Article↗