Lipase-catalyzed acetylation of a twice-prochirally shaped tetraol, 1, gave a mixture of diastereomeric diacetates from which an optically pure derivative belonging to the C2-symmetry group could be isolated.
Benzyl bispidine as an efficient replacement for (−)-sparteine in ring opening polymerisation
作者:Richard Todd、Gabriel Rubio、Daniel J. Hall、Sarah Tempelaar、Andrew P. Dove
DOI:10.1039/c2sc22053a
日期:——
been demonstrated to be an excellent catalyst for the controlled ring-openingpolymerisation (ROP) of lactide and cyclic carbonate monomers. Notably, the polymerisation proceeds with negligible transesterification or epimerisation, with the polymerisation of stereopure L-lactide affording highly crystalline poly(lactide) with a Tm of 156 °C. ROP of racemic lactide results in the observation of a modest
二苄基官能化联吡啶的合成与应用 1-(3,5-双(三氟甲基)苯基)-3-环己基硫脲 (TU)助催化剂已被证明是可控的开环聚合(ROP)的极好催化剂 丙交酯和环状碳酸酯单体。值得注意的是,聚合以可忽略不计的酯交换或差向异构化进行,而立体纯的L-丙交酯的聚合提供了T m为156℃的高度结晶的聚(丙交酯)。外消旋的ROP丙交酯结果观察到适度的立体控制,使得等规链的概率P m = 0.74。一系列替代氢键供体助催化剂的比较显示,TU与二苄基官能化联吡啶一起显示出最高的聚合速率。
Substituent Effects on the Basicity of 3,7-Diazabicyclo[3.3.1]nonanes
Basicity constants for a series of 3,7-diazabicyclo[3.3.1]nonane derivatives in acetonitrile with a variation over 13 orders of magnitude have been determined using a spectrophotometric titration technique. An excellent correlation between basicity and calculated proton affinities obtained at PCM-B3LYP/6-31+G(d)//B3LYP/6-31G(d) level was found. The results are discussed in terms of substituent effects
已使用分光光度滴定技术确定了乙腈中一系列3,7-二氮杂双环[3.3.1]壬烷衍生物的碱性常数,其变化幅度超过13个数量级。发现在PCM-B3LYP / 6-31 + G(d)// B3LYP / 6-31G(d)水平下获得的碱度与计算的质子亲和力之间极好的相关性。根据取代基效应讨论了结果,并将其与15 N NMR化学位移进行了比较。
Stereochemical studies—XVIII
作者:N.S. Zefirov、S.V. Rogozina
DOI:10.1016/s0040-4020(01)97102-9
日期:1974.1
A number of heteroanalogues of bicyclo[3.3.1]nonane containing heteroatoms in 3-, 3,7- and 3,7,9-positions has been synthesized. 1H NMR measurement has shown that the compounds of the types 4,5 and 6 (Y = oxygen) are double-chairs with the “wings” of the molecule flattened. However, a new conformational effect has been found for the sulfur containing compounds of type 5 and 6 (X,Y = sulfur) which show
合成了许多在3-,3,7-和3,7,9-位含有双环[3.3.1]壬烷的杂原子的杂类似物。1个1 H NMR测定表明,类型的化合物4,5和6(Y =氧)是双椅子与“翅膀”的分子平坦化。然而,已经发现对于类型5和6的含硫化合物(X,Y =硫)具有新的构象作用,其显示出明显增加了采用船椅构象的趋势。
High refractive index, durable hard coats
申请人:Pokorny J. Richard
公开号:US20060147702A1
公开(公告)日:2006-07-06
The development of new compositions and new aromatic sulfur acrylate monomers results in improved hardcoat films, and improved optical films that contain the hard coat films. The films provide improved display systems when incorporated thereon. The combination of functionalized zirconia nanoparticles with multifunctional acrylate crosslinkers and high index of refraction aromatic sulfur acrylates, about 1.58 or greater, produces abrasion resistant hard coats that have relatively high refractive indices.
Aqueous solvent dispersible, radiation crosslinkable compounds and oligomers containing poly(ethylenically unsaturated) group-containing components and carboxyl groups are disclosed. Each compound is a monester of a cyclic dicarboxylic acid anhydride and a 2-hydroxyalkylpolyester, said 2-hydroxyalkylpolyester being the ester Jf a polyepoxide with a monoester which is the monoester of a poly(ethylenically-unsaturated)alkanol and a dicarboxylic acid. These compounds and oligomers are useful in the field of graphic arts and protective coatings.