High throughput screening of Monophos instant ligand library leads to a ton-scale asymmetric hydrogenation process

The development of catalytic processes for pharmaceuticals intermediates is often under severe time-pressure. To cope with this constraint, high throughput experimentation (HTE) methods have been implemented for catalyst finding. In this article, we present the HTE protocols put in place at DSM in the area of enantioselective hydrogenation. They mostly rely on libraries of monodentate chiral phosphoramidites ligands. We applied our instant ligand library technology to solve a real-life case, i.e. the asymmetric hydrogenation of an α-substituted cinnamic acid derivative. This has led to a multi-ton scale process.     

含手性膦配体MBPA和邻巯基吡啶配体PyS的过渡金属钯(Ⅱ)化合物的2D NMR研究

利用一维和二维NMR技术,对含手性膦配体MBPA和邻巯基吡啶配体PyS的过渡金属Pd(Ⅱ)化合物Pd(3-MBPA)(PyS)Cl)(1),Pd(2-MBPA)(PyS)Cl)(2)。进行~1H和~(13)C NMR谱分析,归属了所有的~1H和~(13)CNMR谱线,并对配体在配位前后的化学位移的变化作了简单讨论。     

Synthesis and characterization of resins with ligands containing guanidinine derivatives. Cu(II) sorption and coordination properties

A new modification direction of acrylonitrile, vinyl acetate and divinylbenzene terpolymers (A, B) are presented. The aminolysis of nitrile groups of the terpolymers using ethylenediamine or hydroxylamine hydrochloride was a first stage of the modification. The resulting amine groups reacted with dicyandiamide (DCDA), cyanamide (CA) and sodium dicyanimide (SDC) in order to obtain the biguanidyl, guanidyl or nitrilguanidyl derivatives in the polymer side chain, respectively. The properties of all obtained resin such as water regain, nitrogen content, amine and carboxyl group concentration and sorption properties towards Cu(II) from nitric acid solutions were determined. The studies of IR spectra of all the resins were performed. Structures of ligand complexes with Cu(II) were studied using electron paramagnetic resonance spectroscopy.     

Tetrazoles: Unique Capping Ligands and Precursors for Nanostructured Materials

Capping agents play an important role in the colloidal synthesis of nanomaterials because they control the nucleation and growth of particles, as well as their chemical and colloidal stability. During recent years tetrazole derivatives have proven to be advanced capping ligands for the stabilization of semiconductor and metal nanoparticles. Tetrazole‐capped nanoparticles can be prepared by solution‐phase or solventless single precursor approaches using metal derivatives of tetrazoles. The solventless thermolysis of metal tetrazolates can produce both individual semiconductor nanocrystals and nanostructured metal monolithic foams displaying low densities and high surface areas. Alternatively, highly porous nanoparticle 3D assemblies are achieved through the controllable aggregation of tetrazole‐capped particles in solutions. This approach allows for the preparation of non‐ordered hybrid structures consisting of different building blocks, such as mixed semiconductor and metal nanoparticle‐based (aero)gels with tunable compositions. Another unique property of tetrazoles is their complete thermal decomposition, forming only gaseous products, which is employed in the fabrication of organic‐free semiconductor films from tetrazole‐capped nanoparticles. After deposition and subsequent thermal treatment these films exhibit significantly improved electrical transport. The synthetic availability and advances in the functionalization of tetrazoles necessitate further design and study of tetrazole‐capped nanoparticles for various applications.     

Blocking Muscarinic Receptor 3 Attenuates Tumor Growth and Decreases Immunosuppressive and Cholinergic Markers in an Orthotopic Mouse Model of Colorectal Cancer

Tumor cells have evolved to express immunosuppressive molecules allowing their evasion from the host’s immune system. These molecules include programmed death ligands 1 and 2 (PD-L1 and PD-L2). Cancer cells can also produce acetylcholine (ACh), which plays a role in tumor development. Moreover, tumor innervation can stimulate vascularization leading to tumor growth and metastasis. The effects of atropine and muscarinic receptor 3 (M3R) blocker, 1,1-dimethyl-4-diphenylacetoxypiperidinium iodide (4-DAMP), on cancer growth and spread were evaluated in vitro using murine colon cancer cell line, CT-26, and in vivo in an orthotopic mouse model of colorectal cancer. In the in vitro model, atropine and 4-DAMP significantly inhibited CT-26 cell proliferation in a dose dependent manner and induced apoptosis. Atropine attenuated immunosuppressive markers and M3R via inhibition of EGFR/AKT/ERK signaling pathways. However, 4-DAMP showed no effect on the expression of PD-L1, PD-L2, and choline acetyltransferase (ChAT) on CT-26 cells but attenuated M3R by suppressing the phosphorylation of AKT and ERK. Blocking of M3R in vivo decreased tumor growth and expression of immunosuppressive, cholinergic, and angiogenic markers through inhibition of AKT and ERK, leading to an improved immune response against cancer. The expression of immunosuppressive and cholinergic markers may hold potential in determining prognosis and treatment regimens for colorectal cancer patients. This study’s results demonstrate that blocking M3R has pronounced antitumor effects via several mechanisms, including inhibition of immunosuppressive molecules, enhancement of antitumor immune response, and suppression of tumor angiogenesis via suppression of the AKT/ERK signaling pathway. These findings suggest a crosstalk between the cholinergic and immune systems during cancer development. In addition, the cholinergic system influences cancer evasion from the host’s immunity.     

Linked‐BINOL: An Approach towards Practical Asymmetric Multifunctional Catalysis

The development and application of a novel linked‐1,1′‐binaphthol (linked‐BINOL) as an approach towards practical asymmetric multifunctional catalysis is described. Linked‐BINOL was first designed to increase the stability of a Ga‐Li‐BINOL complex against ligand exchange with 4‐methoxyphenol. An oxygen‐containing linked‐BINOL, which is a semi crown ether, was effective in both promoting the formation of a monomer complex and increasing the stability of the Ga‐Li complex. A Ga‐Li‐linked‐BINOL complex promoted the epoxide opening reaction in up to 96% enantiomeric excess (ee). Second, based on the X‐ray structural information of the Ga‐Li‐linked‐BINOL complex, we designed a more stable lanthanide linked‐BINOL complex. An air‐stable, storable, and reusable La‐linked‐BINOL complex promoted the Michael reaction in up to >99% ee. The catalyst activity remained unchanged after storage under air for 4 weeks. Calculations suggested that the linked‐BINOL would function as a pentadentate ligand in a lanthanum complex, thus efficiently improving the stability of the complex. Finally, the linked‐BINOL was applied to a new homobimetallic multifunctional catalysis. A dinuclear Zn‐Zn‐linked‐BINOL complex promoted the enantio‐ and diastereoselective direct aldol reaction in up to 99% ee, where one Zn cation might function as a Lewis acid and the other Zn‐phenoxide as a Brønsted base.     

Werner-type metal complexes of potato starch

It was shown that potato starch formed Werner‐type complexes. In these complexes a metal atom is ligated by the lone electron pairs of hydroxyl groups from d ‐glucose units and phosphate groups in starch. Acetate, chloride and nitrate were counter‐ions to the transition metal atoms. The metal cations bound preferentially to the phosphoric acid moiety of amylopectin, but secondarily they were co‐ordinated by the hydroxyl groups of the d ‐glucose units. This resulted in the formation of clathrate cages in which a significant number of the water molecules were trapped. Such structures were able to co‐ordinate further metal cations. Only Mn(II) and Co(II) ions, with acetate counter‐ions, neither formed clathrate cages nor were co‐ordinated by the hydroxyl groups of the d ‐glucose of starch.     

Carbonaceous fragments of osmium ligand deficient clusters that take part in alkane C-H and C-C bonds cleavage in the presence of molecular hydrogen

The direct participation of carbonaceous ligands of osmium ligand deficient clusters (LDC) in alkane and cycloalkane reactions in the presence of H₂ is proved by¹⁴C-labeling. In contrast to the other metallic catalysts, wherein carbonaceous ligands block active centres, the C-containing ligands of the Os-LDC are active and exhibit at least two functions in alkane and cycloalkane reactions: stabilization of clusters against agglomeration and preservation of active centres.Deceased on the 7th of January 1991.     

原材料物理化学特性对多孔性PTC陶瓷结构与性能的影响

本文研究了以不同物理化学形态的含结晶水有机酸盐草酸氧钛钡为原料时，对多孔性ＰＴＣ陶瓷的结构与性能的影响；以及同时以不同结晶水含量的草酸氧钛钡为主原料时，二者分别对同一块多孔性ＰＴＣ陶瓷的不同结构特征、不同性能特征做出的不同贡献。     

Syntheses and Crystal Structures of Two Inorganic–Organic Hybrid Frameworks Constructed from Pyridine-2,5-Dicarboxylic Acid

Two novel inorganic–organic hybrid frameworks of [Co(2,5-pydc)(4,4′-bipyo)_0.5(H₂O)₃ · 3H₂O] _n (1) and [Cu_1.5Gd(2,5-pydc)₃(2,2′-bipyo)(H₂O)₄ · 2H₂O] _n (2) (2,5-pydc = pyridine-2,5-dicarboxylic acid; 4,4′-bipyo = 4,4′-bipyridine-N,N′-dioxide; 2,2′-bipyo = 2,2′-bipyridine-N,N′-dioxide) were prepared. Both compounds have been characterized by the elemental analyses, IR spectra, TG analysis and the single crystal diffraction. The salient structural feature for both compounds 1 and 2 is that the 1D chain and the mononuclear fragment are connected by strong hydrogen bond interactions to form 2D structure.