Selenated NHC-Pd(II) Pincer Complex Catalyzed, Temperature-Dependent Selective Hydroamination and Oxidative Amination of Olefins: Formation of Enamine Esters and β‑Amino Esters under Solvent-Free and Aerobic Conditions

NHC-Pd(II) pincer catalyzed oxidative amination and hydroamination of olefins is developed under solvent-free aerobic conditions. Reaction offered a temperature-controlled synthesis of (Z)-enamine and β-amino esters to provide easy access and remarkable functional group tolerance for a variety of enamines. The developed approach renders an opportunity of scalability and flexibility, and besides this, the produced enamines can be transformed into many N-containing heterocycles, underscoring its potential usage in synthetic and pharmaceutical chemistry. Moreover, it is the first report for coupling of aniline with styrene

Survival profile of <i>M. smegmatis</i> harboring <i>eis</i> gene of <i>M. tuberculosis</i> H37Rv at different temperatures.

<p>Cells grown at 37°C to log phase were incubated at 37°C, 50°C, 60°C and 70°C for 10 minutes and survival was determined. Data are mean ± standard deviations from three independent experiments.</p

SDS induced changes in the Eis protein.

<p>Panel A. Far-UV CD curves of Eis measured in the presence of different concentrations of SDS ranging from 2 mM to 100 mM or in the absence of SDS. Panel B. Temperature induced changes in secondary structure of Eis either in the absence or presence of 2 mM and 20 mM SDS were monitored using CD by following changes in molar ellipticity at 222 nm. Panel C. The fluorescence spectra of Eis at different temperatures ranging from 37°C to 100°C. Panel D. The fluorescence spectra of Eis at different concentration of SDS. Panel E. The fluorescence spectra of Eis in the abscene or presence of 2 mM SDS at temperatures ranging from 25°C to 100°C.</p

Ru-Catalyzed and Selenium-Directed Selective Formation of <i>ortho</i>- and Dialkenylated Selanes, Mixed Organoselenoethers, and Isoselenochromenes

Herein, the Ru-catalyzed chemo- and regioselective formation of four novel organoselenium compounds is established. Mono- and dialkenylated selanes were formed by the Se-directed o-C–H activation of benzyl(phenyl)selanes with alkynes. Unprecedented debenzylative/dearylative hydroselenations of alkynes were performed by slightly varying the amount of catalyst and temperature. Catalyst-driven direct formation of novel isoselenochromenes is also recorded. Altogether, 45 new organoseleno compounds were synthesized in good amounts with varieties of alkynes and selanes. This is the first report of its kind to deal with the synthesis of novel, challenging, and unusual organoseleno compounds in one reaction

Effect of temperature on the Eis-Acetyl CoA interaction study.

<p>Panel A. Eis-Acetyl CoA interaction studies were done using increasing concentration of Acetyl CoA from 20 µM to 100 µM at 25°C and fluorescence emission spectra were monitored. Stern-Volmer plot used for calculation of binding constant (Ksv) for Acetyl CoA is shown on the right side in Panel A. Panel B. Eis-Acetyl CoA interaction studies were done by recording the fluorescence emission spectra with fixed concentration of Acetyl CoA (20 µM) or without Acetyl CoA but at different temperatures ranging from 25°C to 100°C as mentioned in materials and methods.</p

Intracellular survival of <i>M. smegmatis</i> harboring <i>eis</i> gene of <i>M. tuberculosis</i> H37Rv in THP1 cells.

<p>Survival of intracellular bacteria was counted at 3 h (Panel A), 24 h (Panel B) and 48 h (Panel C) post infection as per the details described in materials and methods. Data are mean ± standard deviations from three independent experiments.</p

Size exclusion chromatography for determination of molecular weight and oligomeric stability.

<p>Panel A. Size-exclusion chromatographic profile for Eis on Superdex 200HR 10/30 column in 20 mM phosphate buffer, pH 8.0 at 25°C. Panel B. standard molecular weight markers Aldolase (158 kDa), Catalase (219 kDa), Ferritin (416 kDa), Thyroglobulin (699 kDa) run under the same conditions for molecular weight determination. Panel C. SDS-PAGE resistance assay. lane 1: unboiled and lane 2: boiled Eis protein. Equal amount of protein was loaded in lanes 1 and 2. H: Hexamers; T: Trimers and M: Monomers. The experimental details are given in materials and methods.</p

Thermostable aminoglycoside acetyltransferase activity of Eis.

<p>Panel A. Size exclusion chromatographic profile of SDS treated Eis. Peak A represents micelles of SDS; Peak H: hexamers; Peak T: trimers and Peak M: monomers of Eis. Panel B. Hexamers, trimers and monomers obtained from SEC in panel A were examined for aminoglycoside acetyltransferase activity. Panel C. Eis protein was incubated at increasing temperatures for 10 mintues and aminoglycoside acetyltransferase activity was assayed. The specific activity was determined over a linear range. The experiment for each sample was performed in triplicate and the mean ± S.D. is represented above the graph. Panel D. The effect of temperatures 60°C, 65°C and 70°C on the secondary structure of Eis protein was measured by recording the CD at the respective temperatures.</p

Size exclusion chromatographic profiles forGdmCl treated Eis on superdex 200HR 10/30 column.

<p>The curves 1, 2, 3, 4 and 5 represent profiles for Eis incubated in 0 M, 1 M, 2 M, 3 M and 4 M GdmCl, respectively.</p

Secondary structural changes of Eis in the presence of different denaturants analyzed by CD.

<p>Panel A. Far-UV CD spectra of native recombinant Eis protein. Panel B. Temperature induced changes in secondary structure of Eis as monitored by following changes in molar ellipticity at 222 nm obtained from far-UV CD curves at increasing (▪) and decreasing (•) temperature. Changes in secondary structure of Eis due to Urea and GdmCl as monitored by following the changes in ellipticity at 222 nm obtained from far-UV CD curves at increasing concentrations of Urea (Panel C) or GdmCl (Panel D).</p