The development of catalytic enantioselective cyanation methods for preparing valuable chiral nitriles is of great interest in the areas of pharmaceutical synthesis and organic chemistry. In this study, we presented an enzymatic enantioselective cyanation strategy for the synthesis of chiral β-hydroxy nitriles using cyanohydrins as cyano sources. By combining enzyme screening and protein engineering
A polymer electrolyte membrane having outstanding water resistance and high thermal resistance, moreover having practical strength required for use as a polymer electrolyte membrane of a solid polymer electrolyte type fuel cell at low price, and a method for producing the polymer electrolyte membrane are provided. A polymer electrolyte comprising a block copolymer comprising one or more of blocks in which sulfonic acid groups are introduced and one or more blocks in which sulfonic acid groups are not substantially introduced wherein at least one block in the block copolymer is a block having aromatic rings in the polymer chain, and a porous membrane, and a fuel cell using the membrane are provided.
And moreover the present invention provides a method for producing a polymer electrolyte membrane comprising the steps of, (i) impregnating some of the pores of a porous membrane with a solution (1) of a polymer electrolyte having a contact angle of less than 90°to said porous membrane, (ii) impregnating a remaining part in the pores of the porous membrane with a solution (2) of a polymer electrolyte having a larger contact angle than that of the solution to said porous membrane, and (iii) removing the solvent.
NBS/DMSO-mediated synthesis of (2,3-dihydrobenzo[<i>b</i>][1,4]oxathiin-3-yl)methanols from aryloxymethylthiiranes
作者:Jun Dong、Jiaxi Xu
DOI:10.1039/c8nj01117f
日期:——
4]oxathiin-3-yl)methanols were synthesized via reactions of aryloxymethylthiiranes and N-bromosuccinimide (NBS) in DMSO under microwave irradiation. The reaction mechanism was proposed as an intramolecular aromatic electrophilic substitution of 1-bromo-2-(aryloxymethyl)thiiran-1-iums, generated from aryloxymethylthiiranes and NBS, and the subsequent DMSO nucleophilic ring opening reaction of thiiran-1-iums followed by
通过芳氧基甲基硫烷和N-溴琥珀酰亚胺(NBS)在DMSO下微波辐射反应合成了(2,3-二氢苯并[ b ] [1,4]氧杂嘧啶-3-基)甲醇。该反应机理被认为是由芳氧基甲基噻喃和NBS生成的1-溴-2-(芳氧基甲基)噻喃-1-鎓的分子内芳族亲电取代,以及随后的噻吩-1-鎓的DMSO亲核开环反应,随后是排水量。当前的方法提供了一种直接和简单的策略,可以从容易获得的芳氧基甲基噻喃有效地制备(2,3-二氢苯并[ b ] [1,4]氧杂蒽-3-基)甲醇。
Facile synthesis of thietanes via ring expansion of thiiranes
作者:Jun Dong、Jiaxi Xu
DOI:10.1039/c6ob02387h
日期:——
Thietanes are pharmaceutically important cores of some biological compounds and intermediates of organic synthesis. Various thietanes were prepared from thiiranes via ring expansion through a reaction with trimethyloxosulfonium iodide in the presence of sodium hydride. The reaction process is a nucleophilic ring-opening reaction of thiiranes with dimethyloxosulfonium methylide, generated from trimethyloxosulfonium