New investigation of Vilsmeier-type reaction using pyrazolones with various amides

New investigation of Vilsmeier-type reaction was evaluated to realize the solvent effect by using pyrazolones to react with various of amides, including formamide, N-methylformamide, N-propylformamide, N-tert-butylformamide, N,N-dimethylformamide (DMF), N,N-diethylformamide (DEF), N,N-dipropylformamide (DPF), N,N-diisopropylformamide, N,N-dibutylformamide, piperidine-1-carbaldehyde, and pyrrolidine-1-carbaldehyde, in the presence of phosphorous oxychloride POCl₃. The unexpected resulting products were observed in this work according to the difference chemoseletivities of substituted amides. The plausible reactive pathways were proposed to explain the experimental result.     

[4+1] Cycloaddition of N-acylimine derivatives with isocyanides: efficient synthesis of 5-aminooxazoles and 5-aminothiazoles

[4+1] Cycloaddition reaction between isocyanides and N-acylimine derivatives generated from N-acyl N,O-acetals acting as isocyanophiles has been developed. These reactions proceeded smoothly and cleanly to afford the corresponding 5-aminooxazoles in high yields. This reaction was extended to the syntheses of 5-aminothiazoles by using N-thioacyl N,O-acetals. A wide range of N-acyl N,O-acetals, N-thioacyl N,O-acetals, and isocyanides were found to be applicable to this reaction.     

Green aldose isomerisation: 2-C-methyl-1,4-lactones from the reaction of Amadori ketoses with calcium hydroxide

Saccharinic acids, branched 2-C-methyl-aldonic acids, may be accessed via a green procedure from aldoses by sequential conversion to an Amadori ketose and treatment with calcium hydroxide; d-galactose and d-glucose are converted to 2-C-methyl-d-lyxono-1,4-lactone (with a small amount of 2-C-methyl-d-xylono-1,4-lactone) and 2-C-methyl-d-ribono-1,4-lactone. Inversion of configuration at C-4 of the branched lactones allows access to 2-C-methyl-l-ribono-1,4-lactone and 2-C-methyl-l-lyxono-1,4-lactone, respectively. d-Xylose affords 2-C-methyl-d-threono-1,4-lactone and 2-C-methyl-d-erythrono-1,4-lactone, whereas l-arabinose, under similar conditions, gave the enantiomers 2-C-methyl-l-threono-1,4-lactone and 2-C-methyl-l-erythrono-1,4-lactone.     

Copolymerization of acrylic acid to nylon-6 by trapped radicals—I. Vapour phase grafting

Film of nylon-6 has been γ-irradiated in vacuo to various doses D. Grafting has been effected by subsequent exposure in vacuo to vapour at 50° of composition 9.1 wt% acrylic acid and 90.9 wt% water. Determinations have been made of total vapour uptake as well as the individual swellings due to monomer and water. For D ? ca. 2 Mrad, the initial rate of grafting R_g increased with D in accord with R_g ∝ D^β with β = 0.45 ± 0.05, thus suggesting bimolecular chain termination. However, for D ? ca. 2 Mrad, there is no further increase in R_g. This is attributed in part to the fact that the radical yield is proportional to dose only for D ? ca. 2.5 Mrad. Diffusion controlled grafting has been predicted elsewhere to be characterized by β = 0.67. Grafting proceeds from the surface and the initial stages are concluded to be essentially free from diffusion control, since (a) β ≠ 0.67, (b) the rate of uptake of monomer vapour >R_g and (c) a large change in film thickness yields only a very small change in R_g.     

Catalytic asymmetric Michael reactions of dibenzyl malonate to α,β-unsaturated N-acylpyrroles using a La(O-iPr)3/Ph-linked-BINOL complex

Catalytic asymmetric Michael reactions of a malonate to acyclic α,β-unsaturated N-acylpyrroles as ester equivalent acceptors are described. A La(O-iPr)₃/(S,S)-linked-BINOL complex, which is suitable for Michael addition to cyclic enones, is not suitable for acyclic α,β-unsaturated N-acylpyrroles. A new (S,S)-Ph-linked-BINOL chiral ligand was developed to improve enantioselectivity, and a La(O-iPr)₃/(S,S)-Ph-linked-BINOL complex with the addition of HFIP afforded Michael adducts in good yield and enantioselectivity (up to 96% ee).     

Yeasts and Lactic Acid Bacteria Mixed-Specie Biofilm Formation is a Promising Cell Immobilization Technology for Ethanol Fermentation

We previously found that some Saccharomyces cerevisiae and Lactobacillus plantarum remarkably formed mixed-specie biofilm in a static co-culture and deduced that this biofilm had potential as immobilized cells. We investigated the application of mixed-specie biofilm formed by S. cerevisiae BY4741 and L. plantarum HM23 for ethanol fermentation in repeated batch cultures. This mixed-specie biofilm was far abundantly formed and far resistant to washing compared with S. cerevisiae single biofilm. Adopting mixed-specie biofilm formed on cellulose beads as immobilized cells, we could produce enough ethanol from 10 or 20 % glucose during ten times repeated batch cultures for a duration of 10 days. Cell numbers of S. cerevisiae and L. plantarum during this period were stable. In mixed-specie biofilm system, though ethanol production was slightly lower compared to S. cerevisiae single-culture system due to by-production of lactate, pH was stably maintained under pH 4 without artificial control suggesting high resistance to contamination. Inoculated model contaminants, Escherichia coli and Bacillus subtilis, were excluded from the system in a short time. From the above results, it was indicated that the mixed-specie biofilm of S. cerevisiae and L. plantarum was a promising immobilized cell for ethanol fermentation for its ethanol productivity and robustness due to high resistance to contamination.     

Decay channels of core excitation resonances in 3d and 4f metal atoms

Photoabsorption, photoelectron, and ejected electron spectra of atomic 3d metals and rare earths in the energy range of the strong 3p→3d and 4d→(4fεf) excitations are presented. TheZ-dependence of the strength, shape and decay channels of the giant resonances is discussed. With increasing Z for the 3d metals the 3p→3d resonances change from almost symmetric lines close to the 3p-ionization limits to broad asymmetric profiles centered well below the 3p-ionization threshold. Autoionization leading to the emission of a 3d electron dominates the decay. For lowZ rare earths the 4d→(4fεf) resonances mainly decay via the emission of a 4d electron whereas for higherZ the emission of a 4f electron takes over.     

Rectangular source integral and recurrence relations

In this paper Hubbell's rectangular source integral H′(a,b), which is a double integral, is expressed as a series of many converging single integrals I_n (a,b). Recurrence relations relate these integrals. Once one integral I₁ is computed, recurrence relations are used to compute other integrals. I₁(a,b) can be computed analytically. H′(a,b) is approximated by considering the first seven terms in the series and the results are found to give good results for various values of a and b. Results are presented for the values of a and b (0.1 to 20 and to 2), respectively. The rate of convergence depends on the values of a and b.     

Suppression of Rice Cryptochrome 1b Decreases Both Melatonin and Expression of Brassinosteroid Biosynthetic Genes Resulting in Salt Tolerance

We investigated the relationship between the blue-light photoreceptor cryptochrome (CRY) and melatonin biosynthesis by generating RNA interference (RNAi) transgenic rice plants that suppress the cryptochrome 1b gene (CRY1b). The resulting CRY1b RNAi rice lines expressed less CRY1b mRNA, but not CRY1a or CRY2 mRNA, suggesting that the suppression is specific to CRY1b. The growth of CRY1b RNAi rice seedlings was enhanced under blue light compared to wild-type growth, providing phenotypic evidence for impaired CRY function. When these CRY1b RNAi rice plants were challenged with cadmium to induce melatonin, wild-type plants produced 100 ng/g fresh weight (FW) melatonin, whereas CRY1b RNAi lines produced 60 ng/g FW melatonin on average, indicating that melatonin biosynthesis requires the CRY photoreceptor. Due to possible feedback regulation, the expression of melatonin biosynthesis genes such as T5H, SNAT1, SNAT2, and COMT was elevated in the CRY1b RNAi lines compared to the wild-type plants. In addition, laminar angles decreased in the CRY1b RNAi lines via the suppression of brassinosteroid (BR) biosynthesis genes such as DWARF. The main cause of the BR decrease in the CRY1b RNAi lines seems to be the suppression of CRY rather than decreased melatonin because the melatonin decrease suppressed DWARF4 rather than DWARF.     

Semiclassical variational study of size effects in neutral and charged jellium droplets

An analytic expression for the total energy of metallic clusters composed ofN identical atoms of valencev and with net chargeQ is obtained by means of a variational solution of the Thomas-Fermi-Weizsäcker energy density functional within the spherical jellium model. The minimum energy is given as an expansion in decreasing powers of the cluster radiusR=r _s Z ^1/3, withZ=vN andr _s the radius per electron of the bulk metal. The coefficients are obtained as functions ofr _s . Terms of volume (R ³), surface (R ²), curvature (R), constant (R ⁰), (1/R) and (1/R ²) are clearly separated in the formula, as well as the different contributions (kinetic, coulombic and exchange-correlation) to each of them. The asymptotic values (R→∞) for the work functions,W(r _s ), and surface energies σ(r _s ), are compared to analogous semiclassical and Kohn-Sham calculations of jellium-like surfaces and to the experimental values. The size dependent behaviour of chemical potentials, μ(R), electron affinities,AF(R), and ionization potentials,IP(R), are easily obtained for any kind of metallic clusters. In particular we discuss the Coulomb and quantum corrections to the coefficients β, δ in the asymptotic formulae:IP?W+β/R andAF?W+δ/R.     

Trans-selective γ-arylation of macrocyclic N-picolinoylcycloalkylamines through palladium-catalyzed methylene sp3 carbon–hydrogen bond activation

While numerous stereoselective methylene β- and γ-carbon–hydrogen activation reactions are reported, there are no examples of trans-selective γ-carbon–hydrogen activation of cyclic compounds. Herein I report the first trans-selective palladium-catalyzed γ-arylation of N-picolinoylcycloalkylamine with aryl iodides. Trans-arylation of macrocyclic N-picolinoylcyclododecylamine proceeded to give trans-3-aryl-N-picolinoylcyclododecylamine as a sole mono-arylated product in up to 85% yield. Other, larger substrates were also applicable to trans-arylation, albeit with lower efficiency. The picolinoyl group of the trans-arylated product was easily removed with zinc and diluted hydrochloric acid.     

Para-selectivity of SAPO-5 and mordenite catalysts in the alkylation of cumene with 2-propanol

Alkylation of cumene with 2-propanol was studied on SAPO-5 and mordenite catalysts. The primary products of the alkylation on every catalyst examined here were p- and m-diisopropylbenzene (DIPB) in a ratio of 75:25. The p-DIPB fraction in DIPB isomers (para-selectivity) decreased with increasing yield of DIPB, due to the secondary reaction of p-DIPB to m-DIPB. On SAPO-5, mordenite and silica-alumina, this secondary reaction proceeds through dealkylation of p-DIPB to cumene, followed by re-alkylation of the resultant cumene to m-DIPB. The dealkylation of p-DIPB would occur preferentially over that of m-DIPB. This was due to the higher reactivity of p-DIPB and probably to the reactant molecular shape selectivity of SAPO-5 and mordenite. The para-selectivity was improved by supporting boron oxide on SAPO-5 and mordenite; this improvement was caused by suppression of the secondary dealkylation of p-DIPB.     

Retardation (Casimir) energy shifts for Rydberg helium-like low-Z ions

The development of storage rings and electromagnetic traps for heavy charged particles is opening up new regimes of atomic physics, including, in particular, spectroscopic studies of Rydberg helium-like ions — with nuclear chargeZ, one electron in the 1s state, and one electron in a near-hydrogenic state of highn andl <n, withn andl the principal and orbital quantum numbers, respectively. We consider the possibility of detecting energy shifts due to retardation, ΔE _ret (n,l), Casimir-like effects. These are quantum electrodynamic (QED) retardation effects associated with the finite speed of light. (As opposed to basically kinematic and dynamic QED effects for small quantum numbersn andl, the appropriate expansion parameter forn andl large for retardation QED corrections is notZ(e ²/?c) but [(Z ? 1)/n ² Z ²](?c/e ²).) We wish to provide some orientation to those planning experiments in the area, with regard to the choices ofn,l, andZ most likely to be able to generate a high-precision confirmation of a retarded interaction. To do so, we provide extensive tables of estimates, for 1s,nl states, of ΔE _ret(n,l), of radiative widths, and ofE, the spin-independent (“electric” fine structure) energy in the absence of retardation shifts, for (nuclear spin zero) ions withZ=2, 6, 8, 16 and 20. These ions might be experimentally accessible in storage rings, and theZ's are low enough that virtual pair production effects may not yet be significant. There is also a brief survey of possible experimental techniques.     

First straightforward synthesis of 2,4-disubstituted benz[g]isoquinoline-3,5,10(2H)-triones, 1,2,3,5-substituted naphtho[3,2,1-de]isoquinoline-4,7-diones, and 6-substituted benzo[h]pyrido[3,4,5-kl]-1,2,3,4-tetrahydroacridine-5,8-diones

Structural modifications to the benz[g]isoquinoline skeleton of N-substituted benz[g]isoquinoline-3,5,10(2H)-triones were envisaged in order to make future SAR studies possible for this type of bioactive compounds. Several N-substituted benz[g]isoquinoline-3,5,10(2H)-triones were converted to novel 2,4-substituted benz[g]isoquinoline-3,5,10(2H)-triones, new tetracyclic 1,2,3,5-substituted naphtho[3,2,1-de]isoquinoline-4,7-diones, and 6-substituted benzo[h]pyrido[3,4,5-kl]-1,2,3,4-tetrahydroacridine-5,8-diones. All the synthesized target compounds represent new heterocyclic systems, which were previously undescribed in the literature.     

Photoisomerization of octyl methoxycinnamate

The octyl-p-methoxy-trans-cinnamate (E-OMC) was exposed to sunlight to induce the E to Z transformation. Octyl-p-methoxy-cis-cinnamate (Z-OMC) was then purified from the mixture of the E- and the Z-OMC using C-18-semi-preparative HPLC. The UV absorption of the Z configuration at various concentrations in various solvents was measured. Molar absorption coefficient of the compound was then calculated. By using the obtained molar absorption coefficient of Z-OMC and of E-OMC, E to Z photoisomerization of octyl methoxycinnamate (OMC) in various solvents at various concentrations could be monitored by C-18 HPLC using UV detector. The result indicates that equilibrium of photoisomerization depends upon concentration and polarity of the solvent used.     

The infrared spectra (500-150 CM−1) of the complexes cis- and trans-[Pt(pyridine)2X2] (X = Cl,Br, I,SCN)

The IR spectra of cis- and trans-[Pt(pyridine)₂X₂] (X = Cl, Br, I, SCN) are discussed. Distinction between the vPt—N and vPt—X bands is based on their relative sensitivities to ¹⁵N-labelling and deuteration of the pyridine ring, to halogen substitution and to ¹⁵NCS-labelling. Two vPt—N and two vPt—X bands are observed in the cis-complexes as required for C_2v symmetry. The D_2h symmetry of the trans-complexes requires one vPt-N and one vPt—X band but additional bands are observed and are ascribed to coupling between vPt—N and vPt—X.     

Efficient synthesis and conformational investigations of cis-pentacenediols

Diisobutylaluminum hydride is utilized to reduce pentacene-6,13-diones to the corresponding diols, useful precursors to functionalized pentacenes. This pathway is mild and efficient, and produces the cis-diols as major products. Further, we found the cis-diols adopt endo conformation, which cannot flip to the exo conformation under ambient conditions. Due to the cis and endo orientation, the cis-diols can be potential bidentates in catalysis, molecular propellers, and optoelectronic devices.     

Reactions of ortho oxy-substituted benzyl and phenacyl bromides in dimethyl sulphoxide

o-Acetoxy- and o-benzoyloxy-benzyl bromides and tosylates oxidatively rearrange in moist dimethyl sulphoxide to o-hydroxybenzyl esters; o-acetoxy- and o-benzoyloxy- phenacyl bromides rearrange to mixtures of 2-hydroxycoumaran-3-ones and o-hydroxyphenacyl esters; o-hydroxyphenacyl bromides also yield 2-hydroxycoumaran-3-ones, together with o-hydroxyphenacyl alcohols. 2-Acetoxybenzaldehyde is reductively rearranged by sodium borohydride to o-hydroxybenzyl acetate.     

Pressure effects of a genuine organic crystalline ferromagnet dupeyredioxyl

We have revealed that the isothermal magnetization M of the genuine organic crystalline dupeyredioxyl (N,N′-dioxy-1,3,5,7-tetramethyl-2,6-diazaadamantane; T_c(0)=1.48 K) observed below 10 K converges on the S=1 Brillouin function B₁((H+λM)/k_BT) with λ=2.4±0.2 or 2zJ/k_B=3.6±0.3 K, where J and z are, respectively, the averaged exchange interactions and coordination numbers for the S=1 spin system. This fact suggests that S=1 is constructed within a molecule via a strong ferromagnetic coupling between two S=1/2 spins on each of the two NO moieties. The modified notation of the Rushbrooke and Wood theory, T_c=2AzJS(S+1)/k_B (A=0.23±0.02 for the three-dimensional Heisenberg systems), is found to quantitatively hold not only for this S=1 spin system but also for other S=1/2 ferromagnets β-phase p-NPNN (2zJ/k_B=3.6 K) and 2,5-DFPNN (2zJ/k_B=2.8 K). Pressure effects of this compound have been studied under the hydrostatic pressure (P) up to 15 kbar. T_c(P) is revealed to show a negative pressure effect with the initial gradient a=d(T_c(P))/dP=−0.047 kbar⁻¹, nearly the same value for other organic ferromagnets as β-phase p-NPNN (−0.048 kbar⁻¹) and p-Cl-TEMPO radical (−0.03 kbar⁻¹), in contrast to the positive pressure effect for genuine antiferromagnets such as TANOL (a=+0.15 kbar⁻¹). Microscopically, different from the above two ferromagnets, the pressure-induced destruction of the orthogonality of molecular orbitals associated with the two NO moieties plays an effective role in reducing the intramolecular ferromagnetic interaction J₀. The possible weaker intermolecular interactions other than J₀ and J are also expected to be more susceptible to the stress of pressure to result in the reduction of their values perhaps even changing their sign, just as in the case of β-phase NPNN or p-Cl-TEMPO.