A new library of flavone derivatives targeting two active sites of monoamine oxidases ("aromatic cage" and substrate cavity) were designed and synthesized using click chemistry (CuAAC reaction) between 6-N -2-phenyl chromones (Az1-Az2) and a series of alkynes (k1-k20). Their inhibitory activities against MAO isoforms (MAO-A and MAO-B) are evaluated. Compounds with fluorine, amide bonds, or amino bonds have shown better inhibition. The most potent flavone MAO inhibitor studied is Az2k19 (1.6 μm for MAO-A, 2.1 μm for MAO-B), while Az1k15 and Az2k15 displayed better selectivity toward MAO-B (SI > 10). Docking studies are in accordance with our hypothesis that these inhibitors are most likely located at both the substrate cavity and the "aromatic cage". Our results show that it is considerable to develop new MAO inhibitors from C6 substitution of flavone derivatives and that these compounds are also potential for the treatment of diseases associated with MAOs.

p-Nitrophenyl esters with a short-chain carboxylic group, such as p-nitrophenyl acetate (p-NPA) and p-nitrophenyl butyrate (p-NPB), could be effectively hydrolyzed by ammonium salts. p-Nitrophenyl esters were usually used as substrates to assay the lipase/esterase activity. Ammonium sulfate precipitation was often used to purify proteins, and some ammonium salts were usually used as nitrogen sources or inorganic salts for the lipase/esterase production. To study the effect of ammonium salts on the assay of the lipase/esterase activity, the contributing factors of hydrolysis of p-NPA/p-NPB catalyzed by ammonium salts were investigated. The lipase activities were compared in the presence and absence of ammonium sulfate. The hydrolysis reaction could be catalyzed under neutral and alkaline circumstances. The hydrolysis rate increased with the increase in the reaction temperature or the concentration of ammonium ion. When p-NPA was employed as the substrate for the analysis of the lipase/esterase activity, the effect of ammonium sulfate on the analysis could be neutralized by setting a control when the concentration of ammonium sulfate was less than 40% saturation. However, when the concentration of ammonium sulfate increased from 40% to 100% saturation, the enzyme activities decreased about 13-40%, which could not be ignored for accurate analysis of the enzyme activity.

A very efficient solid-phase synthesis of substituted benzofuran using polymer-supported selenium resin is described. The advantages of the new method are good yields, high purity, straightforward operations, broad range and high diversity of products, lack of odor, and good stability of the resins. The easy work-up procedure makes the method suitable for building parallel libraries.Low-melting-point solid. 1 H NMR and 13 C NMR spectral data were consistent with data reported in the literature; [15] MS (EI) m/z 176 Synthesis of substituted benzofuran using selenium-bound resin