An engineered variant of subtilisin BPN', termed subtiligase, which efficiently ligates esterified peptides in aqueous solution, was used for the complete synthesis of ribonuclease (RNase) A that contains unnatural catalytic residues. Fully active RNase A (124 residues long) was produced in milligram quantities by stepwise ligation of six esterified peptide fragments (each 12 to 30 residues lon...

in recent years, zinc oxid nanotubes have attracted much attention. the direct use of , zinc oxidnanotubes modified by sio2 as recoverable catalysts for organic reactions is very rare. the catalystswere characterized by xrd. the average particle size of zno catalysts is 57 nm and there are highdensitydefects on nanotubes surfaces . a simple and efficient method for the imidazol derivativessynth...

A series of new tetrasubstituted imidazoles 2-phenyl-3-(1, 4, 5-triphenyl-1H-imidazol-2-yl)-1H-indole derivatives substituted with –F, Cl, Br, I,-OCH3 and -NHCOCH3 were synthesized using a multicomponent reaction. The compounds were obtained in good yields by easy workup and with high purity

A  convenient  and  efficient  one-pot  four-component  synthesis  of  1,  2,  4,  5-tetrasubstituted  imidazoles  using  nano  TiO2  as  a  recyclable  catalyst  is  reported.  The results  show  that  the  methodology  has  several  advantages  such  as  low  loading  of catalyst,  excellent  yield,  short  reaction  time,  operational  simplicity  and  solvent-free conditions.

A synthetic strategy based on reactions of cyclic imine oxides, namely 2H-imidazole 1-oxides, with thiophenols mediated by acetyl chloride was successfully applied as a convenient tool to obtain series novel azaheterocyclic molecules, including water-soluble hydrochloride forms. Optimized reaction conditions found herein for the nucleophilic substitution hydrogen (SNH) in non-aromatic substrate...

Human carbonic anhydrases (CAs) are zinc metalloenzymes that catalyze the hydration and dehydration of CO2 and HCO3 (-), respectively. The reaction follows a ping-pong mechanism, in which the rate-limiting step is the transfer of a proton from the zinc-bound solvent (OH(-)/H2O) in/out of the active site via His64, which is widely believed to be the proton-shuttling residue. The decreased cataly...

To be fairly general and catalyst is easily separated by magnetic devices and can be reused without any apparent loss of activity for the reaction. Fe3O4 nanoparticles were prepared by chemical coprecipitation method and was found to be a mild and effective catalyst for the efficient, one-pot, three-component synthesis of 2,4,5-trisubstituted imidazoles at room temperature under ultrasound irra...

Azoles are a class of antimicrobial drugs used clinically to treat yeast and fungal infections. Against pathogenic yeast and fungi, azoles act by inhibiting the activity of the cytochrome P450 Cyp51, which is involved in the synthesis of a critical component of the yeast and fungal cell membrane. Azoles have antibacterial activity, including against mycobacteria, but the basis for this activity...