Development of palladium(II)-catalyzed oxidative cyclization of olefinic keto and/or lactone esters

A highly efficient palladium-catalyzed oxidative cyclization of olefinic keto and/or lactone esters, which features a catalytic cyclization employing one atmosphere of oxygen as a reoxidizing agent, is developed.     

A new isoelectric focusing system for fast two-dimensional gel electrophoresis using a low-concentration polyacrylamide gel supported by a loose multifilament string.

A new isoelectric focusing (IEF) system for two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) has been proposed. In this system, a super-soft and tough IEF gel was achieved by casting polyacrylamide gel down to 2.0% T using a loose multifilament string (LMS) of nylon as a gel support. The IEF apparatus for the LMS-gel, fabricated from acrylic boards, had a cooling water chamber, and eliminated the need of electrode solutions by directly connecting the two ends of individual gels to platinum electrodes. The carrier ampholyte-generated pH gradients using the new IEF system was stable over a long duration of time and a wide range of voltages, and the IEF time became shorter using a 2.0% T gel than using a 4.0% T gel. Also, the LMS-gels prepared in different runs exhibited excellent reproducibility. The new IEF system was applied to 2-D PAGE of a chicken skeletal muscle extract, and it was found that the protein loading capacity, protein entry into the LMS-gels, and protein transfer efficiency from the first-dimensional to the second-dimensional gels were significantly improved by using a low-concentration (2.5% T) gel. Also, proteins of high molecular weight of more than 200 kDa were observed in the 2-D maps, and therefore the new IEF system has a very good potential to be applied for fast 2-D PAGE of high molecular-weight proteins.     

Matrix Projection Exposure Using an Analogue Liquid Crystal Display Panel in Place of a Reticle

The most serious problems for the matrix projection exposure using a liquid crystal display (LCD) panel in place of a reticle are largely solved by a new breakthrough method. LCD matrix exposure is effective for small volume productions of print circuits, screen masks, micromachine parts, and other items. Since no reticles are needed, all reticle costs are saved, and turnaround times required for changing the patterns are greatly shortened. However, in the conventional method, pattern widths and positions were strictly restricted depending on the geometric size and pitch of the liquid crystal cells. In this paper, a new concept appointing the cell brightness grades continuously using an analogue interface LCD panel is proposed. Calculating the image intensity distributions for various appointments of cell brightness balances to print same wide patterns, it is clarified that the pattern widths and positions are not much different if the pattern widths are wider than 2 cell pitches of the LCD panel. Maximum width and position variations are less than ± 10% even when the patterns are printed at arbitrary positions, of course including halfway ones. The calculated results are proved by experiments using an analogue LCD panel with a cell pitch of 15 μm. Though the cell size are 13 × 10 μm², and different in x and y directions, almost same wide line-and-space patterns are successfully printed at all positions by only one exposure. It is not necessary to shift the reticle for overlapping exposures to print smooth patterns. Oblique patterns and complicated Chinese character patterns are also printed at arbitrary positions. The new breakthrough technology will make the LCD matrix exposure promising for wide uses of printing various rough patterns easily at small costs.     

Semi‐interpenetrating polymer networks composed of diisocyanate‐bridged 4‐arm star‐shaped l‐lactide oligomers and poly(ε‐caprolactone)

Semi‐interpenetrating polymer networks (semi‐IPNs) were prepared by reactions of 2,4‐tolylene diisocyanate (TDI) and hydroxy‐terminated 4‐arm star‐shaped l ‐lactide oligomers (H4LAO_n's) with the degrees of polymerization of lactate unit per one arm, n = 3, 5, and 10 in the presence of poly(ε‐caprolactone) (PCL). Morphologies, thermal, and mechanical properties of the TDI‐bridged H4LAO_n (TH4LAO_n)/PCL semi‐IPNs were evaluated by comparing with those of poly(l ‐lactide) (PLA)/PCL blends. Compatibility between the two components of the TH4LAO_n/PCL semi‐IPN with a PCL content not more than 50 wt % was much better than those of the PLA/PCL blends with the same PCL content. All the TH4LAO_n networks were substantially amorphous and their tan δ peak or glass transition temperatures increased with decreasing n value. Most of the semi‐IPNs did not show clear glass transition temperature related to both the components. Tensile toughness and elongation at break for all the TH4LAO_n/PCL semi‐IPNs were much higher than those for the PLA/PCL blends with the same PCL content. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1420–1428     

An asymmetric synthesis of (+)-monomorine I

The synthesis of (+)-monomorine I, an indolizidine alkaloid isolated from Monomorium pharaonis, has been achieved. The 2,6-cis-piperidine ring moiety of (+)-monomorine I was constructed using diastereoselective aminopalladation. Chain elongation via cross-metathesis using Hoveyda-Grubbs 2nd catalyst followed by deprotection of the Cbz group and cyclic reductive hydroamination afforded (+)-monomorine I.     

An efficient catalytic oxidation of p-Alkoxypenols to p-quinones using tetrabutylammonium bromide and oxone

A catalytic oxidation of p-alkoxyphenols was developed using tetrabutylammonium bromide (TBAB) and Oxone(?). The reaction of p-alkoxyphenol (1) with a catalytic amount of TBAB in the presence of Oxone(?) as a co-oxidant in acetonitrile-water (2 : 1) gave the corresponding p-quinone (2) in excellent yield without special treatment.     

Crystals in Minutes: Instant On‐Site Microcrystallisation of Various Flavours of the CYP102A1 (P450BM3) Haem Domain

Despite CYP102A1 (P450BM3) representing one of the most extensively researched metalloenzymes, crystallisation of its haem domain upon modification can be a challenge. Crystal structures are indispensable for the efficient structure‐based design of P450BM3 as a biocatalyst. The abietane diterpenoid derivative N‐abietoyl‐l ‐tryptophan (AbiATrp) is an outstanding crystallisation accelerator for the wild‐type P450BM3 haem domain, with visible crystals forming within 2 hours and diffracting to a near‐atomic resolution of 1.22 Å. Using these crystals as seeds in a cross‐microseeding approach, an assortment of P450BM3 haem domain crystal structures, containing previously uncrystallisable decoy molecules and diverse artificial metalloporphyrins binding various ligand molecules, as well as heavily tagged haem‐domain variants, could be determined. Some of the structures reported herein could be used as models of different stages of the P450BM3 catalytic cycle.     

A 3‐Pyridyl‐5,15‐Diazaporphyrin Nickel(II) Complex as a Bidentate Metalloligand for Transition Metals

3‐Pyridyl‐5,15‐diazaporphyrin nickel(II) serves as a bidentate metalloligand for platinum(II), ruthenium(II), and rhenium(I) metal centers. Single‐crystal X‐ray diffraction analysis of these metal complexes unambiguously reveals the presence of a dative bond between the outer metal center and the meso‐nitrogen atom. The UV/Vis absorption spectra of the complexes show substantially red‐shifted bands which are perturbed by outer‐metal coordination. This is due to the contribution of metal‐to‐ligand charge transfer interactions.     

Efficient method for large-scale preparation of two components H and I of Sg-6 saponins from whole seeds of wild soybean (Glycine soja Sieb. and Zucc.)

New saponin components, Sg-6 saponins, have been recently reported from the seeds of wild soybean (Glycine soja) which may have specific health benefits. To evaluate the possible health benefits, a large amount of Sg-6 saponins are needed, but general group A acetyl saponins and new Sg-6 saponins are eluted in overlapping peaks by ordinal preparative high-performance liquid chromatography and/or open column methods. A new method is proposed in this report. This method includes (1) deacetylation of group A acetyl saponins in alkali condition with KOH, (2) precipitation of Sg-6 saponins in acid condition with HCl, (3) recovery of Sg-6 saponins with aqueous methanol from the precipitate, and (4) elution of Sg-6 saponins by preparative reverse-phase open column. With this method, from 450?g of wild soybean whole seed powder, about 1?g of Sg-6 saponins (mixture of six components) was clearly separated from other saponins with 61% recovery.     

Purification by centrifugal partition chromatography of amphiphilic compounds, glycolipids and pseudo-glycolipids synthesized by using cells

Centrifugal partition chromatography (CPC) was applied to separate amphiphilic glycolipids and pseudo-glycolipids synthesized by using cells. Neutral and acidic lipid fractions were isolated by CPC under suitable conditions respectively. Separation of neutral lipid, Gb3-type and Gb4-type oligosaccharide synthesized by using cells, was performed with a two-phase solvent system composed of chloroform-methanol-water at a volume ratio of 5:6:4. On the other hand, separation of acidic lipid, GM3-type oligosaccharide synthesized by using cells, and ganglioside extracted from rat brain were performed with a two-phase solvent system composed of butanol-ethanol-1% acetic acid at a volume ratio of 4:1:5. 8.3mg of Gb3 analogue, 5.1mg of Gb4 analogue, and 19.5mg of GM3 analogue were purified from 3.2l of culture medium obtained by incubation of African green-monkey kidney (Vero) cells with 50 microM n-dodecyl beta-lactoside using CPC.