Methyl 4‐O‐β‐D‐mannopyranosyl β‐D‐xylopyranoside

Methyl β‐D‐mannopyranosyl‐(1→4)‐β‐D‐xylopyranoside, C₁₂H₂₂O₁₀, (I), crystallizes as colorless needles from water, with two crystallographically independent molecules, (IA) and (IB), comprising the asymmetric unit. The internal glycosidic linkage conformation in molecule (IA) is characterized by a ϕ′ torsion angle (O5′_Man—C1′_Man—O1′_Man—C4_Xyl; Man is mannose and Xyl is xylose) of −88.38 (17)° and a ψ′ torsion angle (C1′_Man—O1′_Man—C4_Xyl—C5_Xyl) of −149.22 (15)°, whereas the corresponding torsion angles in molecule (IB) are −89.82 (17) and −159.98 (14)°, respectively. Ring atom numbering conforms to the convention in which C1 denotes the anomeric C atom, and C5 and C6 denote the hydroxymethyl (–CH₂OH) C atom in the β‐Xylp and β‐Manp residues, respectively. By comparison, the internal glycosidic linkage in the major disorder component of the structurally related disaccharide, methyl β‐D‐galactopyranosyl‐(1→4)‐β‐D‐xylopyranoside), (II) [Zhang, Oliver & Serriani (2012). Acta Cryst. C 68 , o7–o11], is characterized by ϕ′ = −85.7 (6)° and ψ′ = −141.6 (8)°. Inter‐residue hydrogen bonding is observed between atoms O3_Xyl and O5′_Man in both (IA) and (IB) [O3_Xyl...O5′_Man internuclear distances = 2.7268 (16) and 2.6920 (17) Å, respectively], analogous to the inter‐residue hydrogen bond detected between atoms O3_Xyl and O5′_Gal in (II). Exocyclic hydroxymethyl group conformation in the β‐Manp residue of (IA) is gauche–gauche, whereas that in the β‐Manp residue of (IB) is gauche–trans.     

乙基二茂铁与乙酰丙酸甲酯的缩合反应

以多聚磷酸-浓硫酸-甲醇为催化剂和环已烷为溶剂,由乙基二茂铁与乙酰丙酸甲酯缩合合成4,4-双（乙基二茂铁基）成酸甲酯,转化率73%,产率84%。正交实验法获得的适宜反应条件：乙基二茂铁55mmol,乙酰丙酸甲酯75mmol,浓硫酸3.0mL,环已烷20mL,甲醇11mL。通过元素分析、IR、^1H NMR和^13C NMR确证了缩合产物的结构。     

2D‐ and 3D‐microstructured biodegradable polyester resins

Biodegradable polyester resins were prepared via photo crosslinking of functional polyesters obtained by copolymerization of ε‐caprolactone and the functional cyclic esters γ‐acryloyloxy‐ε‐caprolactone (ACL) and γ‐methacryloyloxy‐ε‐caprolactone (MCL). The cyclic esters were prepared via Baeyer‐Villiger oxidation of the corresponding 4‐acyloyloxy‐cyclohexanone derivatives. Copolymers with different content of either acryloyloxy or methacryloyloxy functional groups were prepared via catalyzed ring‐opening polymerization (ROP) of γ‐acyloyloxy‐ε‐caprolactones and ε‐caprolactone using Al(OiPr)₃ as catalyst and initiator. 2D‐ and 3D‐micropatterning of the copolymers was performed via UV‐crosslinking of polymer films on a suitable substrate and by UV replica molding on both rigid and elastic masters, showing the processability of these novel functional polyesters and their potential as substrates for biomedical devices. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6789–6800, 2008     

Trimethylsilyl Triflate - Catalysid Acetal Formation Between Silylated Hexopyranosides and Methyl Pyruvate1

Abstract

Trimethylsilyl ethers of 2,3-di-O-substituted glycopyranosides or their thioglycopyranoside analogues were reacted with methyl pyruvate in the presence of trimethylsilyl triflate to give pyruvylated hexo-pyranosides in yields of 60–75%, and the ratio of the diastereoisomers was found to be ca. 1:1. The reaction can also be applied for cellobioside derivatives, providing suitable building blocks for the preparation of pyruvate-containing oligosaccharides.     

Massively parallel implementation of 3D‐RISM calculation with volumetric 3D‐FFT

A new three‐dimensional reference interaction site model (3D‐RISM) program for massively parallel machines combined with the volumetric 3D fast Fourier transform (3D‐FFT) was developed, and tested on the RIKEN K supercomputer. The ordinary parallel 3D‐RISM program has a limitation on the number of parallelizations because of the limitations of the slab‐type 3D‐FFT. The volumetric 3D‐FFT relieves this limitation drastically. We tested the 3D‐RISM calculation on the large and fine calculation cell (2048³ grid points) on 16,384 nodes, each having eight CPU cores. The new 3D‐RISM program achieved excellent scalability to the parallelization, running on the RIKEN K supercomputer. As a benchmark application, we employed the program, combined with molecular dynamics simulation, to analyze the oligomerization process of chymotrypsin Inhibitor 2 mutant. The results demonstrate that the massive parallel 3D‐RISM program is effective to analyze the hydration properties of the large biomolecular systems. © 2014 Wiley Periodicals, Inc.     

Separation of D‐psicose and D‐fructose using simulated moving bed chromatography

Simulated moving bed (SMB) processes have been widely used in the sugar industries with ion‐exchange resin as a stationary phase. D ‐Psicose, a rare monosaccharide known as a valuable pharmaceutical substrate, was synthesized by the enzymatic conversion from D ‐fructose. The SMB process was adopted to separate D ‐psicose from D ‐fructose. Before the SMB experiment, the reaction mixture including D ‐psicose and D ‐fructose was treated by a deashing process to remove contaminants, such as buffers, proteins, and other organic materials. Four columns packed with Dowex 50WX4‐Ca²⁺ (200–400 mesh) ion‐exchange resins were used in the four‐zone SMB. Single‐step frontal analysis was performed to estimate the isotherm parameters of each monosaccharide. The operating conditions of the SMB process were determined based on the Equilibrium Theory. According to the simulation of the SMB process, the purity and yield of extract product (D ‐psicose) achieved were 99.04 and 97.46%, respectively and those of raffinate product (D ‐fructose) were 99.06 and 99.53%, respectively. Under the optimized operating condition, complete separation (extract purity = 99.36%, raffinate purity = 99.67%) was achieved experimentally.     

Hierarchical Self‐Assembly of Supramolecular Spintronic Modules into 1D‐ and 2D‐Architectures with Emergence of Magnetic Properties

Hierarchical self‐assembly of complex supramolecular architectures allows for the emergence of novel properties at each level of complexity. The reaction of the ligand components A and B with Fe^II cations generates the [2×2] grid‐type functional building modules 1 and 2 , presenting spin‐transition properties and preorganizing an array of coordination sites that sets the stage for a second assembly step. Indeed, binding of La^III ions to 1 and of Ag^I ions to 2 leads to a 1D columnar superstructure 3 and to a wall‐like 2D layer 4 , respectively, with concomitant modulation of the magnetic properties of 1 and 2 . Thus, to each of the two levels of structural complexity generated by the two sequential self‐assembly steps corresponds the emergence of novel functional features.     

Syntheses of 1‐thio‐D‐xylose and D‐ribose esters of diorganoarsinous acids and their anticancer activity

Several thio‐D ‐xylose and D ‐ribose esters of dialkylarsinous acids have been synthesized. The crystal structure of 1‐S‐dimethylarsino‐β‐D ‐xylopyranose, 7a, has been obtained. Growth inhibition studies of about 60 strains of human cancer cells have been obtained in vitro for compounds 6a, 7a, 13 , and 14 . The results reveal that these compounds display a strong inhibition to subpanels of leukemia cells in vitro and high selectivity in inhibiting the growth of cancer cells. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:199–206, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20388     

Polycondensation of activated L‐valine and L‐leucine esters with various lewis acids

To develop a novel polycondensation method for the preparation of poly (amino acid)s, we screened a transition metal or a rare‐earth triflate as a Lewis acid for the polycondensation of activated amino acid esters in N,N‐dimethylformamide solutions at room temperature. The polymerizations of 4‐nitrophenyl L ‐leucinate ( 1a ) and 4‐nitrophenyl L ‐valinate ( 1b ) scarcely proceeded without any Lewis acid at room temperature. In the presence of 5 mol % metal triflates, especially scandium(III) trifluoromethanesulfonate, the polymerizations of both monomers were promoted effectively. The products, which were collected by the reaction mixture being poured into water, were recognized as poly(L ‐valine)s by Fourier transform infrared spectroscopy, gel permeation chromatography analysis, and ¹H NMR spectroscopy. These results showed that a metal triflate as a Lewis acid could coordinate to a carbonyl oxygen of activated L ‐valinate and L ‐leucinate even in a highly polar solvent, such as N,N‐dimethylformamide; therefore, the polymerizations of activated L ‐valinate and L ‐leucinate were promoted. Because steric hindrance derived from the isobutyl group in 1b was less than that of the isopropyl unit in 1a , the effect of the metals was not as sensitive for the polymerization of 1b . © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 543–547, 2007     

Combined 1H, 13C and 11B NMR and mass spectral assignments of boronate complexes of D‐(+)‐glucose,D‐(+)‐mannose,methyl‐α‐D‐glucopyranoside,methyl‐β‐D‐galactopyranoside and methyl‐α‐D‐mannopyranoside

Complex formation between N‐butylboronic acid and D ‐(+)‐glucose, D ‐(+)‐mannose, methyl‐α‐D ‐glucopyranoside, methyl‐β‐D ‐galactopyranoside and methyl α‐D ‐mannopyranoside under neutral conditions was investigated by ¹H, ¹³C and ¹¹B NMR spectroscopy and gas chromatography–mass spectrometry (GC–MS) D ‐(+)‐Glucose and D ‐(+)‐mannose formed complexes where the boronates are attached to the 1,2:4,6‐ and 2,3:5,6‐positions of the furanose forms, respectively. On the other hand, the boronic acid binds to the 4,6‐positions of the two methyl derivatives of glucose and galactose. Methyl α‐D ‐mannopyranoside binds two boronates at the 2,3:4,6‐positions. ¹¹B NMR was used to show the ring size of the complexed sugars and the boronate. GC–MS confirmed the assignments. Copyright © 2003 John Wiley & Sons, Ltd.     

Microwave Assisted Condensation of Aromatic Methyl Groups with Aromatic Aldehydes

Abstract

Aromatic aldehydes are condensed with 2,4‐dinitro‐1,5‐dimethylbenzene in a Siegrist type coupling. The reported method features microwave irradiation, solvent‐free conditions, and a catalytic amount of piperidine to give a high yield of the corresponding 1,3‐bisstyryl‐4,6‐dinitrobenzenes within a few minutes.     

3D‐Printed Microfluidics

The advent of soft lithography allowed for an unprecedented expansion in the field of microfluidics. However, the vast majority of PDMS microfluidic devices are still made with extensive manual labor, are tethered to bulky control systems, and have cumbersome user interfaces, which all render commercialization difficult. On the other hand, 3D printing has begun to embrace the range of sizes and materials that appeal to the developers of microfluidic devices. Prior to fabrication, a design is digitally built as a detailed 3D CAD file. The design can be assembled in modules by remotely collaborating teams, and its mechanical and fluidic behavior can be simulated using finite‐element modeling. As structures are created by adding materials without the need for etching or dissolution, processing is environmentally friendly and economically efficient. We predict that in the next few years, 3D printing will replace most PDMS and plastic molding techniques in academia.     

Theoretical studies on triaryamine‐based p‐type D‐D‐π‐A sensitizer

Development of triaryamine‐based nonmetallic dye sensitizers is a hot topic in the solar cell research. A series of triaryamine‐based dyes WS1 – WS7 were designed with W1 as the prototype. Density functional theory (DFT) and time‐dependent‐DFT calculations were used to investigate the effects of the attached donor D on the absorption spectra and electronic properties of the dyes. The light‐harvesting efficiency (LHE), hole injection force (ΔG_inj), dye regeneration force (ΔG_reg), and charge recombination force (ΔG_CR) for all the dyes were predicted. The insertion of D not only results in a red shift in the absorption spectra for all dyes but also achieves a broader absorption for visible light. Compared with that of the prototype, the absorption peak of the dye WS7 has a red shift of 95 nm and an oscillator strength increase of 29%. The absorption peak of WS7 is wider and stronger, and the absorption range extends to 900 nm. The LHE and ΔG_reg values of WS7 are 0.991 and ?1.49 eV, respectively. On overall evaluation, WS7 is a promising candidate of a p‐type dye sensitizer with good light absorption and dye regeneration efficiency.