Synthesis of 2-decenedioic acid (royal jelly acid) by sequential carbonylation of butadiene catalyzed by a palladium—phosphine complex and dicobalt octacarbonyl

Carbonylation of butadiene in t-butyl alcohol catalyzed by a palladium complex gave t-butyl-3,8-nonadienoate (I). Further carbonylation of I in methanol with Co₂(CO)₈ afforded t-butylmethyl-3-decenedioate (II) as the main product. Hydrolysis and base-catalyzed isomerization of II produced E-2-decenedioic acid.     

Evaluation and comparison of high-sensitivity immunoradiometric assay kits for thyroid stimulating hormone

Fundamental and clinical characteristics of 3 kinds of high-sensitivity immunoradiometric assay (IRMA) kits for thyroid stimulating hormone (TSH). i.e., RIA BEADS II (kit A), TSH kit Daiichi II (kit B) and Ab tube TSH 'Eiken' (kit C) and one conventional radioimmunoassay (RIA) kit, i.e., TSH kit Daiichi (kit D), were studied. In the recovery test and the reproducibility test, there was no significant difference between the 4 kits. The sensitivities of kits A, B and C were much higher than that of kit D, and those IRMA kits were sensitive enough to distinguish hyperthyroidism from normal samples. For low concentrations of TSH (less than 5 microU/ml), the data from kits D, B, C and A tended to show higher values in that order. The correlation between the data measured by kits B and D, and the tendency of kit A toward lower values agreed well with other reports.     

Isospecific polymerizations of alkyl methacrylates with a bis(alkyl)Yb complex and formation of stereocomplexes with syndiotactic poly(alkyl methacrylate)s

Yb[C(SiMe₃)₃]₂ initiates the living polymerization of methyl methacrylate (MMA) at −78°C to give the polymer with M_n of 51.0×10⁴ (M_w/M_n=1.1) and high isotacticity (97%) in a quantitative yield. Mixing of the acetone solution of resulting polymer (M_n=16.3×10⁴) with the acetone solution of syndiotactic poly(MMA) (M_n=15.7×10⁴) prepared by the (C₅Me₅)₂SmMe(THF) initiator produces desired stereocomplex in high yield bearing very high T_m whose tensile modulus is higher than the respective isotactic and syndiotactic poly(MMA)s. Yb[C(SiMe₃)₃]₂ also generated isotactic (98%) poly[2-(dimethylamino)ethyl methacrylate] (DMEMA), and (C₅Me₅)₂SmMe(THF) affords the syndiotactic (97%) polymer in high yields. The combination of isotactic poly(MMA)-block-poly(DMEMA) (97/3) and syndiotactic poly(MMA)-block-poly(DMEMA) (97/3) provides the amphiphathic stereocomplex. In sharp contrast to the catalysis of Yb[C(SiMe₃)₃]₂ in toluene, the addition of THF or HMPA resulted in the formation of syndio-rich poly(MMA).     

Synthesis of novel imidazole-4,5-dicarboxylic acid derivatives

A convenient general method for the synthesis of unsymmetrical imidazole-4,5-dicarboxylic acid derivatives is described. The key intermediates are 5,10-dioxo-5H,10H-diimidazo[1,5-a:1′,5′-d[pyrazine-1,6-dicarboxylic acid, -1,6-dicarboxylic ester and -1,6-dicarboxamide.     

XPS Analysis of the Aging of Thin,Adhesion Promoting,Fluorocarbon Treatments of DC Plasma Polymers

Plasma polymer treatment of aluminum alloys has recently been shown to improve adhesion of primer coatings, thereby reducing the corrosion of thusly protected panels to the levels afforded by conventional chromate conversion coating. One particular plasma polymer system, comprised of a 50 nm trimethylsilane DC plasma polymer capped by an ultrathin layer modified by DC hexafluoroethane plasma treatment, has shown tremendous adhesion increases to a wide variety of primers, yielding a coating that is virtually unremovable with conventional stripping applications. An application window was empirically deduced regarding this improved adhesion, indicating that the primer needed to be applied within 5 days of plasma treatment to display the tenacious adhesion to panels. In an effort to elucidate the differences between fresh and aged panels, an X-ray photoelectron spectroscopy (XPS) time study of this system was undertaken. Some direct correlation to this time frame was observed in the XPS data, indicating that a particular fluorocarbon structure in the films modified upon continued atmospheric exposure, rearranging the local bonding environment by introducing additional C—C bonding with an increase in oxygen incorporation.     

Role of metal matrix modifier in ashing and beginning of the atomization process in graphite furnace-atomic absorption spectrometry

Summary It has been shown that Pb, Sn and In form alloys with the Pd matrix modifier during the ashing and the beginning of the atomization process in graphite furnace atomic absorption spectrometry.Pb and Sn were chosen as analytes and Ag, Sb, Cu, Au, Pt, Pd, Cd, and Mg as co-existing elements or matrix modifiers. The activity coefficients of Pb in the alloys Pb-Ag and Pb-Sb are similar to the value of Pb alone (or about 1.0), and those in the alloys Pb-Au, Pb-Pt and Pb-Mg are lower than the value of 1.0; in particular the activity coefficients of Sn in the alloy Sn-Pd is extremely low. The activity coefficients of Pb in the alloys Pb-Cd and Pb-Cu are higher than 1.0.The movement of volatilization to higher effective temperatures in the atomization were studied; it was found that: 1) Where the activity coefficient of the analyte was lower than 1.0, intermetallic compounds were formed and the atomization shifted to higher temperatures. 2) Atomization was not altered (even though the activity coefficients were different from 1.0) if the modifier elements formed alloys with Pb, which had melting temperatures lower than the ashing and the initial temperatures of the atomization of Pb. 3) For metals such as Mg, which are neither reduced to metal nor form alloys with the analyte during the ashing and the atomization process, the role as matrix modifier is different, as has also been studied herein.     

Plasma-substrate interaction: Effect of volatile oligomers in silicone rubber on plasma polymerization of fluorine-containing monomers

The cause of the conspicous Si content consistently observed on plasma polymers deposited on silicone rubber was investigated in this study. Plasma polymers of tetrafluoroethylene and of hexafluoroethane were deposited on the inside surface of Silastic tubings with and without oligomers by using a semicontinuous plasma polymerization reactor. This tube coating reactor is unique in the sense that the only surface which interacts with the plasma is the substrate surface (i.e., inside wall of tubing) and that plasma polymerization occurs in a very small volume of 3.3-mm-I.D. and 2-cm-long section of tubing at any given time. These two factors render the reactor a suitable system for the investigation of plasma-substrate surface interaction. Silastic tubings free of oligomers were prepared by extracting the tubings as received with distilled n-hexane for 3 h which yielded a 3% weight loss. It was found that the conspicuous Si content noted previously was not occasioned by the migration of oligomers through the plasma polymers but was caused by the redeposition of plasma copolymers formed from a mixture of the feed-in monomer and the silicon-containing volatile components evolved from the silicone rubber when exposed to the plasma. The presence of Si-containing compounds in the plasma evidently interfered with the plasma polymerization of tetrafluoroethylene and hexafluoroethane. Without volatile oligomers (the extracted samples), ESCA analysis indicated that the plasma polymers contained large amounts of CF₃, CF₂, and CF moieties, just like most typical plasma polymers of these monomers deposited on nonreactive substrates. With the presence of volatile oligomers, the fluorine content decreased drastically and a significant increase of oxygen-containing and silicon-containing moieties was observed. The influence of the volatile oligomers in the substrate on the balance between ablation and polymerization in plasma polymerization and its energy input level dependence (manifested by W/FM) were studied as well. The results were also discussed in relation to the bicyclic rapid step-growth polymerization mechanism.     

Solvent‐induced reversible color changes in block copolymer films and new locking method of structural colors

The well‐defined polystyrene‐block‐poly(4‐vinylpyridine) [PS‐block‐P4VP (SV1); lamellar morphology] and polyisoprene‐block‐poly(α‐methyl styrene) [PI‐block‐PMS (IMS1); PI spherical morphology] diblock copolymers were prepared by sequential anionic polymerization techniques. The segregated chains in the P4VP lamellar layers of the SV1 film (PS lamellae: 41 nm; P4VP lamellae: 51 nm) were crosslinked with 1,4‐dibromobutane. This crosslinked film was insoluble in organic solvents such as benzene and chloroform (CHCl₃) and exhibited various structural colors under the swollen state. The IMS1 film (body‐centered cubic lattice, diameter of PI spheres: 53 nm) was soaked in the mixture of CHCl₃/hexane (1 : 10, v/v). This solvent system resulted in the swelling of PI spherical domains. The transmitted and reflected light color through the swollen film changed to a deep blue. Such color changes were reversible upon swelling in solvent and evaporation of the solvent. Subsequently, photofunctional diethyldithiocarbamate (DC) groups were introduced into the PS block of the parent block copolymer IMS1 by means of polymer reactions. The locking of the cubic lattice was performed with living radical graft copolymerization from DC groups of swollen as‐cast film in methyl methacrylate (MMA) under UV irradiation. The locking of structural colors such as blue and green was also achieved, varying the content of poly(methyl methacrylate) (PMMA) grafted chains. Copyright © 2005 John Wiley & Sons, Ltd.     

Methods for the synthesis of 5,6,7,8-tetrahydro-1,8-naphthyridine fragments for alphaVbeta3 integrin antagonists

The preparation of 3-(5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)propan-1-amine 2a and 3-[(7R)-7-methyl-5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl]propan-1-amine 2b, key intermediates in the synthesis of alpha(V)beta(3) antagonists, is described. The syntheses rely on the efficient double Sonogashira reactions of 2,5-dibromopyridine 3 with acetylenic alcohols 4a/4b and protected propargylamines 10a-e followed by Chichibabin cyclizations of 3,3'-pyridine-2,5-diyldipropan-1-amines 9a/9b.     

Continuous particle separation in a microchannel having asymmetrically arranged multiple branches

A new method for continuous size separation and collection of particles in microfabricated devices, asymmetric pinched flow fractionation (AsPFF), has been proposed and demonstrated. This method improves the separation scheme of pinched flow fractionation (PFF), which utilizes a laminar flow profile inside a microchannel. In this study, multiple branch channels with different channel dimensions were arranged at the end of the pinched segment, so that the flow rate distributions to each branch channel were varied, and a large part of the liquid was forced to go through one branch channel (drain channel). In the proposed channel system, the flow profile inside the microchannel was asymmetrically amplified, enabling the separation of one-order smaller particles compared with PFF. After introducing the method, we examined the effect of the asymmetric amplification by controlling the outlet of the drain channel. Also, a mixture of 1.0 approximately 5.0 microm particles was separated, and erythrocytes were successfully separated from blood. The results indicate that the AsPFF method could be applied to the separation of much smaller-size particles, since more precise separation can be achieved simply by changing the geometries of branch channels.