Photoinduced depolymerization of poly(olefin sulfone)s possessing photobase generator side‐chains: Effect of spacer‐chain length

Photoinduced depolymerization of poly(olefin sulfone)s possessing photobase generators in the side‐chain was investigated. Irradiation with UV light generated base on the side‐chains and induced depolymerization based on proton abstraction on the main‐chain. The effect of the length of the spacer chain, which connects the photobase‐generating moiety to the polymer main chain on the photoinduced depolymerization, also was investigated. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3873–3880     

Synthesis and Characterization of Metabolites and Potential Impurities of the Antiulcerative Drug Tenatoprazole

Tenatoprazole (Ulsacare^®) is a recently developed antiulcerative drug used for the treatment of both erosive and nonerosive gastroesophageal reflux disease. During the bulk synthesis of tenatoprazole, we have observed four impurities (tenatoprazole N‐oxide, tenatoprazole sulfone N‐oxide, N‐methyl tenatoprazole, and desmethoxy tenatoprazole) and two metabolites (tenatoprazole sulfide and tenatoprazole sulfone). The present work describes the synthesis and characterization of these impurities.     

聚芳醚砜薄膜的气体透过行为

研究了一系列聚芳醚砜的Ｈ２、ＣＯ２、Ｏ２、Ｎ２和ＣＨ４气体透过性能，讨论了其气体透过的温度依赖性。与双酚Ａ聚砜（ＰＳＦ）相比，几种新型聚芳醚砜的气体透过系数和气体选择系数同时有所提高。通过聚合物的分子链段活动性和自由体积数据系列变化，讨论了气体透过速率与分子结构的关系。     

Catalytic Asymmetric Synthesis of Allylic Alcohols and Derivatives and their Applications in Organic Synthesis

Allylic alcohols represent an important and highly versatile class of chiral building blocks for organic synthesis. This Review summarizes the plethora of methods developed for the catalytic asymmetric synthesis of enantioenriched allylic alcohols. These include: dynamic kinetic resolution (DKR/DKAT), nucleophilic 1,2‐addition to carbonyl groups, allylic substitution, oxidation of C? H bonds, the addition of O nucleophiles to π systems, reduction of unsaturated carbonyl compounds, and an alternative route from enantioenriched propargylic alcohols. Furthermore, these catalytic asymmetric processes are exemplified by their applications in the syntheses of complex molecules such as natural products and potential therapeutic agents.     

Improved Synthesis of Cyclic Tertiary Allylic Alcohols by Asymmetric 1,2‐Addition of AlMe3 to Enones

The development of an improved protocol for the enantioselective Rh^I/binap‐catalysed 1,2‐addition of AlMe₃ to cyclic enones is reported. ³¹P NMR analysis of the reaction revealed that the catalyst in its resting state is a chloride‐bridged dimer. This insight led to the use of AgBF₄ as an additive for in situ activation of the dimeric precatalyst. Thus, the catalyst loading can now be reduced to only 1 mol % with respect to rhodium. Various 5–7‐membered cyclic enones can be transformed into tertiary allylic alcohols with excellent levels of enantioselectivity and high yields. The obtained products are versatile synthetic building blocks, shown by a highly enantioselective formal total synthesis of the pheromone (?)‐frontalin as well as formation of a bicyclic lactone that has the core structure of the natural flavour component “wine lactone”.     

Radical ring‐opening polymerization of five‐membered cyclic vinyl sulfone using p‐toluenesulfonyl halides

Radical ring‐opening polymerizations of a five‐membered cyclic vinyl sulfone monomer, 2‐vinylthiolane‐1,1‐dioxide (VTDO), was carried out by using p‐toluenesulfonyl iodide (TosI) and bromide (TosBr) as radical initiators, and the corresponding ring‐opened polymer (PVTDO) was obtained. Both TosI and TosBr were found to work as the radical initiators for the polymerization of VTDO in bulk. The use of TosI gave PVTDOs with a broad, multimodal distribution of molecular weight in low yields. When 10 mol % of TosBr was employed, the isolated yield of PVTDO reached 49%, and the obtained PVTDO had a relatively narrow, monomodal molecular weight distribution of 1.8 with an M_n of 4100. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

ZrO_2/S_2O_8~(2-)固体超强酸高效催化合成二芳砜化合物

报道了以ZrO_2／S_2O_8～(2-)固体超强酸为催化剂，在无溶剂条件下，依照 傅一克反应的原理，由芳香磺酰氯与芳香化合物作用合成了一系列二芳砜化合物， 收率为79％～93％．此方法具有操作简便，催化剂价廉易得、活性高、对环境友好 、可回收重复使用等优点．     

Synthesis,characterization, and blends of high temperature poly(arylether sulfone)s

The preparation of poly(4-oxy-1,4-phenylenesulfonyl-4,4′-biphenylene-4-sulfonylphenylene) (PBP) has been accomplished by the base mediated, polycondensation reaction between two biphenyl containing monomers. The bisphenol, 4,4′-bis[(4-hydroxyphenyl) sulfonyl]biphenyl (HSB), was reacted with 4,4′-bis[(4-chlorophenyl)sulfonyl]-biphenyl (CSB) in tetramethylene sulfone solvent. The highest mechanical properties and glass transition temperature was observed for polymer PBP with a reduced viscosity around 1.0 dL/g. Consequently, the current synthesis route provides polymer with higher properties than other historical preparative routes. Blends of PBP with a different poly(ether sulfone) were miscible based on the observance of a single glass transition temperature. The T_gs of the polymer blends exhibited an unusual positive deviation from the weighted linear averages of the components.     

4,4＇-二苯氧基二苯砜、4,4＇-二苯氧基二苯酮、对苯二甲酰氯三元共聚物的合成

聚醚酮醚酮酮;4;4＇-二苯氧基二苯砜、4;4＇-二苯氧基二苯酮、对苯二甲酰氯三元共聚物的合成;聚醚砜醚酮酮;低温溶液浓缩聚     

Allylic Hydroxylation Through Acid Catalysed Epoxy Ring Opening of Betulinic Acid Derivatives

Acid catalysed epoxy ring opening of several lupane type triterpenoids leads to unusual allylic hydroxylation. The reaction involves the formation of epoxide by m‐chloroperbenzoic acid followed by the treatment of mineral acid. The simple methodology finds utility to introduce a hydroxyl function at the allylic position in these triterpenoids, which is otherwise quite difficult.