Unlocking the Drug Potential of the Bryostatin Family: Recent Advances in Product Synthesis and Biomedical Applications

Bryostatins are a class of naturally occurring macrocyclic lactones with a unique fast developing portfolio of clinical applications, including treatment of AIDS, Alzheimer's disease, and cancer. This comprehensive account summarizes the recent progress (2014–present) in the development of bryostatins, including their total synthesis and biomedical applications. An emphasis is placed on the discussion of bryostatin 1 , the most-studied analogue to date. This review highlights the synthetic and biological challenges of bryostatins and provides an outlook on their future development.     

Synthesis and comparative study on polyetherimides from isomeric 4,4′-isopropylidenediphenoxy bis(phthalic anhydride)s

Two isomers of commercial 4,4′-(4,4′-isopropylidenediphenoxy) bis(phthalic anhydride) (4,4′-BPADA), that is, 3,4′-(4,4′-isopropylidenediphenoxy) bis(phthalic anhydride) (3,4′-BPADA) and 3,3′-(4,4′-isopropylidenediphenoxy) bis(phthalic anhydride) (3,3′-BPADA), were synthesized through aromatic nucleophilic substitution from nitrophthalonitrile and bisphenol A. 3,4′-BPADA was first synthesized from two intermediates, that is, 3-(4-[4-hydroxyphenylisopropylidene] phenoxy) phthalonitrile (3-BPADN) and 3,4′-(4,4′-isopropylidenediphenoxy) bis(phthalonitrile) (3,4′-BPATN). The corresponding three series of polyetherimides (PEIs) were prepared with two representative aromatic diamines (4,4′-oxydianiline and m-phenylenediamine (m-PDA)) via two-step procedure and chemical imidization. Isomeric polyimides showed T_gs from 206 to 256°C in nitrogen and T_d5%s from 488 to 511°C in argon, good mechanical properties (tensile moduli of 2.3–3.3 GPa, tensile strengths of 70–96 MPa, and elongations at break of 3.2%–5.1%), and good solubility. With the introduction of 3-substituted phthalimide unit, PEIs displayed higher T_g values, lower strengths and elongations, better solubility and larger d-spacings. The rheological properties of thermoplastic polyimide resins based on the BPADA isomers were investigated, which showed that polyetherimide PEI-3b derived from 3,3′-BPADA and m-PDA had the lowest melt viscosity among the isomers, indicating that the melt processibility had been greatly improved.     

非Hermitian正定线性方程组的外推的HSS迭代方法

为了高效地求解大型稀疏非Hermitian正定线性方程组，在白中治、Golub和Ng提出的Hermitian和反Hermitian分裂（HSS）迭代法的基础上，通过引入新的参数并结合迭代法的松弛技术，对HSS迭代方法进行加速，提出了一种新的外推的HSS迭代方法（EHSS），并研究了该方法的收敛性.数值例子表明：通过参数值的选择，新方法比HSS方法具有更快的收敛速度和更少的迭代次数，选择了合适的参数值后，可以提高HSS方法的收敛效率.     

On the existence of positive least energy solutions for a coupled Schrödinger system with critical exponent

In this paper, we consider the following coupled Schrödinger system with critical exponent: where is a smooth bounded domain, λ > 0,μ≥0, and . Under certain conditions on λ and μ, we show that this problem has at least one positive least energy solution. Copyright © 2016 John Wiley & Sons, Ltd.     

萘酰亚胺取代修饰4,4′-螺双环戊并[2,1-b∶3,4-b′]二噻吩化合物的合成制备及其在有机薄膜光伏器件中的应用研究

近年来,新型有机非富勒烯受体的开发极大地促进了有机聚合物太阳能电池效率的不断突破。其中具有空间非平面结构的新型非富勒烯受体材料是该领域的一个研究热点。本文选取1,8-萘酰亚胺(NMI)作为受电子单元,合成制备了基于螺[4,4]双环戊[2,1-b∶3,4-b′]二噻吩核心单元的空间非平面化合物SCPDT-(NMI)4及对应的基于环戊[2,1-b∶3,4-b′]二噻吩以及环戊[2,1-b∶3,4-b′]二噻吩-4-酮的线性模型化合物CPDT-(NMI)2和CPDT-O-(NMI)2。在此基础上,详细研究了3个化合物的光谱吸收、荧光光谱以及循环伏安电化学性质。结果表明,具有螺形结构的SCPDT-(NMI)4因其非平面结构以及较高的分子内空间位阻,导致其吸收光谱与线性化合物CPDT-(NMI)2相比出现了11nm的蓝移。固体薄膜吸收光谱结果表明,这一系列化合物具有弱的分子间相互作用。电化学循环伏安测试结果表明,所合成的3个化合物均有可逆的氧化还原过程。据此测得化合物的LUMO能级大致为-3.5~-3.8eV之间,可作为电子受体用于有机薄膜光伏电池。利用所合成的萘酰亚胺修饰的化合物作为电子受体,PBDB-T作为电子给体制备了有机太阳能电池器件。器件实验结果表明,基于空间非平面SCPDT-(NMI)4的器件光电转换效率达到了1.16%,远高于以线性分子CPDT-(NMI)_2作为受体的器件效率(0.11%)。荧光光谱猝灭实验结果表明,所合成的萘酰亚胺化合物与聚合物之间不完全的电子转移是影响器件性能的最主要因素。     

Frenkel Defect-modulated Anti-thermal Quenching Luminescence in Lanthanide-doped Sc2(WO4)3

Although large amount of effort has been invested in combating thermal quenching that severely degrades the performance of luminescent materials particularly at high temperatures, not much affirmative progress has been realized. Herein, we demonstrate that the Frenkel defect formed via controlled annealing of Sc₂(WO₄)₃:Ln (Ln=Yb, Er, Eu, Tb, Sm), can work as energy reservoir and back-transfer the stored excitation energy to Ln³⁺ upon heating. Therefore, except routine anti-thermal quenching, thermally enhanced 415-fold downshifting and 405-fold upconversion luminescence are even obtained in Sc₂(WO₄)₃:Yb/Er, which has set a record of both the Yb³⁺-Er³⁺ energy transfer efficiency (>85 %) and the working temperature at 500 and 1073 K, respectively. Moreover, this design strategy is extendable to other hosts possessing Frenkel defect, and modulation of which directly determines whether enhanced or decreased luminescence can be obtained. This discovery has paved new avenues to reliable generation of high-temperature luminescence.     

Organophosphine bearing multiple hydrogen-bond donors for asymmetric Michael addition reaction of 1-oxoindane-2-carboxylic acid ester via dual-reagent catalysis

Multiple hydrogen bonds containing nucleophilic phosphines derived from dipeptide dual-reagents catalyzed asymmetric Michael addition reactions between indene esters and activated olefins in high yields and good to excellent enantioselectivities under mild reaction conditions. The success of current highly selective reactions should provide inspiration for expansion to other reactions and would open up new paradigms for the synthesis of indanone derivatives bearing chiral quaternary carbon centers.     

肿瘤乏氧靶向响应的罗丹明荧光探针及其成像介导手术治疗

基于罗丹明的良好荧光性能, 经化学偶联反应制备并表征了一个偶氮乏氧特异响应的“Off-On”型荧光成像探针(FY-4). 从分子层面证实了其荧光“Off-On”性能和响应机制; 在L02正常细胞及4T1, HeLa和A549肿瘤细胞层面考察了其对受试细胞株的毒性和不同乏氧时间的荧光成像性能; 再利用4T1肿瘤模型, 分别以肿瘤原位注射和尾静脉注射的方式考察了其荧光成像性能, 并探究了其荧光成像介导切除肿瘤性能, 最后还考察了FY-4的生物安全性. 结果表明, FY-4有高的肿瘤乏氧靶向特异“关-开”响应的荧光成像差异显影及荧光成像介导切除肿瘤的潜能, 结合其良好的光物理性能、 生物安全性和明晰的给药时间等特性, 有望为生物医学荧光成像介导肿瘤切除提供新的研究工具.