Enantioselective solvent-free synthesis of 3-alkyl-3-hydroxy-2-oxoindoles catalyzed by binam-prolinamides

Highly asymmetric aldol reaction of isatins and ketones catalyzed by chiral bifunctional primary-amine organocatalyst on water

Herein, we have reported an environmentally friendly asymmetric aldol reaction between isatins and ketones catalyzed by double-hydrogen-bonded primary amine organocatalysts on water under mild conditions. Enantioenriched 3-hydroxy-2-oxindoles were obtained in high yields (up to 99%) and excellent stereoselectivities (up to 99 : 1 dr and 99% ee) under optimal conditions. Furthermore, the model reaction involving isatin and cyclohexanone was successfully scaled to 10 mmol with no reduction in yield or stereoselectivity. In addition, the catalyst was recovered via simple filtration and was subsequently reused on water, which highlights its good application potential.

Antibacterial activities of the chemical constituents of Schizophyllum commune MST7-3 collected from coal area

Two fusidane-type active compounds (6 and 7) and five new ones (1-5), along with other nine known compounds (8-16) were isolated from the metabolites of Schizophyllum commune MST7-3. Their structures were elucidated on the basis of spectroscopic analysis. The absolute configurations of compounds 2 and 3 were established by Mosher's method and optical rotation. Compounds 6 and 7 showed significant antibacterial activities against Stenotrophomonas maltophilia with MIC values of 4 μg/mL and 16 μg/mL, respectively.

Synthesis of 4-Hydroxy-4-(4-nitrophenyl)butan-2-one using p-Nitro Benzaldehyde and Acetone in Aqueous Micellar Media using L-Proline

When the asymmetric aldol reactions are catalyzed by amino acids in water, a certain amount of organic solvents such as ethanol, tetrahydrofuran still had to combine with water to dissolve the organic aldehydes and promote the reaction. But to protect the environment our aim is to completely eliminate the use of organic solvent, therefore we have started to investigate a new system for amino acids catalyzed aldol reaction in water without using any organic solvents. Mainly we use organic solvent to form a homogeneous phase for all reactants which is not possible if the solvent is water, as it makes most organic substances spasingly soluble in water. This drawback could be overcome if we use surfactants, which solubilise organic compounds in water. Thereafter, we planned to use cetyl trimethyl ammonium bromide (CTAB) as surfactant to solubilise the substrate p-nitrobenzaldehyde (PNB) and to perform in this aqueous micellar solution a L-proline catalyzed aldol reaction. A quite different mechanism has been proposed in water.

C 2-Symmetric pyrrolidine-derived squaramides as recyclable organocatalysts for asymmetric Michael reactions

Novel sustainable organocatalysts applicable to asymmetric synthesis of active pharmaceutical ingredients are developed.