PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 14719923

Multicomponent reactions are accelerated in water.

Michael C Pirrung·Koushik Das Sarma
View original source ↗Export metadata ↓

Abstract

Two multicomponent reactions, the Ugi and Passerini reactions, are accelerated by the use of aqueous solutions. The rate enhancements compared to those by organic solvents can approach 300-fold. Reactions performed in water offer another advantage that products are often insoluble, permitting direct isolation by precipitation. The methods were applied to the preparation of three small combinatorial libraries.

Explore related subjects

Carboxylic AcidsChemistry, OrganicKetonesKineticsLactamsSolutionsWaterJournal ArticleResearch Support, U.S. Gov't, P.H.S.

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Michael C Pirrung, Koushik Das Sarma. 2004-01-21. Multicomponent reactions are accelerated in water.. https://doi.org/10.1021/ja038583a

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

New macrocyclic compound as chiral shift reagent for carboxylic acids.

[structure: see text] We have prepared a novel chiral macrocyclic compound 3 from a C2-symmetric aminonaphthol in a high yield. Enantiomeric acids have large nonequivalent chemical shifts (up to 0.80 ppm) in the presence of 3 in 1H NMR (500 MHz) spectra. Quantitative analyses of a series of mandelic acids with different enantiomeric purities show that host 3 is an excellent chemical shift reagent for chiral carboxylic acids.

Carboxylic Acids↗
PubMed2007

Functional analysis of Kluyveromyces lactis carboxylic acids permeases: heterologous expression of KlJEN1 and KlJEN2 genes.

The present work describes a detailed physiological and molecular characterization of the mechanisms of transport of carboxylic acids in Kluyveromyces lactis. This yeast species presents two homologue genes to JEN1 of Saccharomyces cerevisiae: KlJEN1 encodes a monocarboxylate permease and KlJEN2 encodes a dicarboxylic acid permease. In the strain K. lactis GG1888, expression of these genes does not require an inducer and activity for both transport systems was observed in glucose-grown cells. To confirm their key role for carboxylic acids transport in K. lactis, null mutants were analyzed. Heterologous expression in S. cerevisiae has been performed and chimeric fusions with GFP showed their proper localization in the plasma membrane. S. cerevisiae jen1delta cells transformed with KlJEN1 recovered the capacity to use lactic acid, as well as to transport labeled lactic acid by a mediated mechanism. When KlJEN2 was heterologously expressed, S. cerevisiae transformants gained the ability to transport labeled succinic and malic acids by a mediated mechanism, exhibiting, however, a poor growth in malic acid containing media. The results confirmed the role of KlJen1p and KlJen2p as mono and dicarboxylic acids permeases, respectively, not subjected to glucose repression, being fully functional in S. cerevisiae.

Carboxylic Acids↗
PubMed2007

Effect of carboxylate-binding mode on metal binding/selectivity and function in proteins.

We delineate the factors governing the carboxylate-binding mode (monodentate vs bidentate) in metalloproteins. We reveal how the carboxylate-binding mode affects the binding affinity and selectivity of a metal ion as well as the function of a metalloprotein using Ca2+-binding proteins and enzymes (ribonuclease H1, phosphoserine phosphatase, and ribonucleotide reductase) as examples. The collected data indicate that a carboxylate monodentate left arrow over right arrow bidentate switch, in addition to other structural factors, could be used to fine tune the metal-binding site affinity and/or selectivity, thus modifying the function/properties of the metalloprotein.

Carboxylic Acids↗