l-Proline supported on ionic liquid-modified magnetic nanoparticles as a highly efficient and reusable organocatalyst for direct asymmetric aldol reaction in water
作者:Yu Kong、Rong Tan、Lili Zhao、Donghong Yin
DOI:10.1039/c3gc40772a
日期:——
catalyst. The resulting L-proline catalyst was efficient for directasymmetricaldolreaction in water without the need for organic solvents and co-catalysts. Such efficiency is attributed to the fact that the IL moiety facilitated the accessibility of hydrophobic reactants to active sites in water and stabilized the formed enamine intermediate during the reaction. High activity (yield = 92%), diastereoselectivity
A method for stabilizing the cis prolyl peptide bond: influence of an unusual n→π∗ interaction in 1,3-oxazine and 1,3-thiazine containing peptidomimetics
作者:Damodara N. Reddy、Ravula Thirupathi、Shama Tumminakatti、Erode N. Prabhakaran
DOI:10.1016/j.tetlet.2012.06.031
日期:2012.8
The cis/trans isomer ratios of the Xaa-Pyr (Pyr = pyrrolidine) 3 degrees amide bonds are significantly high (similar to 90% cis) in the novel peptidomimetics where Pyr contains 1,3-oxazine (Oxa) or 1,3-thiazine (Thi) at its 2 position. We find that an unusual n -> pi(i-1)* interaction, selectively stabilizes the cis conformer and the n X n repulsion destabilizes the trans conformer of these molecules. Both these electronic effects oppose the steric effects in the 3 degrees amide bond. The structural requirements for manifestation of these electronic effects are determined. (c) 2012 Elsevier Ltd. All rights reserved.
Synthesis and Isolation of 5,6-Dihydro-4<i>H</i>-1,3-Oxazine Hydrobromides by Autocyclization of <i>N</i>-(3-Bromopropyl)amides
作者:Damodara N. Reddy、Erode N. Prabhakaran
DOI:10.1021/jo101955q
日期:2011.1.21
5,6-Dihydro-4H-1,3-oxazine hydrobromides have been synthesized by the nucleophilic autocyclo-O-alkylation of N-(3-bromopropyl)amides under neutral conditions in chloroform. It is found that electron-donating amide alpha-substituents influence the autocyclization efficiency.
Prolinamide functionalized polyacrylonitrile fiber with tunable linker length and surface microenvironment as efficient catalyst for Knoevenagel condensation and related multicomponent tandem reactions
attaching amines to fiber matrix as well as the constructed hydrophobic microenvironment by linker group within the surface layers of fiber materials effectively promotes the reactions. In addition, the good swollen capacity of fiber in solvent ensure that the reaction proceed well. Fiber catalyst PANPA−2F modified by prolinamide with a C2 alkyl chain exhibited the best catalytic performance and can
Disclosed are compounds of formula I: or pharmaceutically acceptable salts thereof. Compounds of formula I are anti-microbials that inhibit, for instance, Mycobacterium tuberculosis (Mtb) H37Ra. Compounds of formula I also have anti-tubercular activity, exhibit limited cytotoxicity, and inhibit protein synthesis. Processes for making compounds of formula I are also disclosed, as well as methods of using compounds of formula I for the treatment of bacterial infections, particularly tuberculosis.