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81.
Alkylesters of orthophosphoric acids have been used for alkylation of phenols1, anilines2, and nitrogen heterocyclic compounds.3 However, no example is reported on their use as an alkoxylating agent for aromatic amines. We have found that alkyl phosphates can act as alkoxylating agents for aromatic diamines in the presence of H2O or aqueous H3PO4. We now report the one-step dialkoxylation of aromatic diamines such as diaminoanthracene and -naphthalene by trialkyl phosphates.  相似文献   
82.
New conductive thermotropic liquid crystalline materials having a piperazine ring in the central core: 1-[4-(9-decenyloxy)phenyl]-4-alkylpiperazines (6) were synthesized. The mesomorphic behaviours of these compounds and their conductivity in the liquid crystal phase were measured. The principal features of these compounds are to exhibit a smectic B phase around room temperature (for example 6: Cr 50 SmB 81 I, °C) and to exhibit a large dark current (6d: 430 μA cm?2, applied voltage 20 V, at 70°C) in the smectic B phase.  相似文献   
83.
Abstract

The formose reaction, by which a complex mixture of sugars and sugar alcohols (the so-called formose) are produced by the base-catalyzed condensation of formaldehyde, has received much attention in connection with the prebiotic synthesis of carbohydrates2 and the microbial utilization of formose.3–5 Formose, however, has not been useful yet, because of the complexity of this product mixture (Fig. 1a). Therefore, it seemed desirable to make the reaction more selective.  相似文献   
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86.
Structural and morphological control is an effective approach for improvement of electrochemical properties in rechargeable batteries. One‐dimensionally assembled structure composed of NASICON‐type Na3V2(PO4)3 nanoparticles were fabricated through an electrospinning method to meet the requirements for the development of efficient electrode materials in Na‐ion batteries. High‐temperature treatment of electrospun precursor fibers under an argon flow provides a nonwoven fabric of nanowires comprising crystallographically oriented nanoparticles of NASICON‐type Na3V2(PO4)3 within a carbon sheath. The mesostructure comprising NASICON‐type Na3V2(PO4)3 and carbon give a short sodium‐ion transport pass and an efficient electron conduction pass. Electrochemical properties of NASICON‐type Na3V2(PO4)3 are improved on the basis of one‐dimensional nanostructures designed in the present study.  相似文献   
87.
Lolitrems are tremorgenic indole diterpenes that exhibit a unique 5/6 bicyclic system of the indole moiety. Although genetic analysis has indicated that the prenyltransferase LtmE and the cytochrome P450 LtmJ are involved in the construction of this unique structure, the detailed mechanism remains to be elucidated. Herein, we report the reconstitution of the biosynthetic pathway for lolitrems employing a recently established genome‐editing technique for the expression host Aspergillus oryzae. Heterologous expression and bioconversion of the various intermediates revealed that LtmJ catalyzes multistep oxidation to furnish the lolitrem core. We also isolated the key reaction intermediate with an epoxyalcohol moiety. This observation allowed us to establish the mechanism of radical‐induced cyclization, which was firmly supported by density functional theory calculations and a model experiment with a synthetic analogue.  相似文献   
88.
Synthesis and deprotonation reactions of half‐sandwich iridium complexes bearing a vicinal dioxime ligand were studied. Treatment of [{Cp*IrCl(μ‐Cl)}2] (Cp*=η5‐C5Me5) with dimethylglyoxime (LH2) at an Ir:LH2 ratio of 1:1 afforded the cationic dioxime iridium complex [Cp*IrCl(LH2)]Cl ( 1 ). The chlorido complex 1 undergoes stepwise and reversible deprotonation with potassium carbonate to give the oxime–oximato complex [Cp*IrCl(LH)] ( 2 ) and the anionic dioximato(2?) complex K[Cp*IrCl(L)] ( 3 ) sequentially. Meanwhile, twofold deprotonation of the sulfato complex [Cp*Ir(SO4)(LH2)] ( 4 ) resulted in the formation of the oximato‐bridged dinuclear complex [{Cp*Ir(μ‐L)}2] ( 5 ). X‐ray analyses disclosed their supramolecular structures with one‐dimensional infinite chain ( 1 and 2 ), hexagonal open channels ( 3 ), and a tetrameric rhomboid ( 4 ) featuring multiple intermolecular hydrogen bonds and electrostatic interactions.  相似文献   
89.
In this paper, we consider a mixed boundary value problem to a class of nonlinear operators containing $p(\cdot )$-Laplacian. More precisely, we are concerned with the problem with the Dirichlet condition on a part of the boundary and the Steklov boundary condition on an another part of the boundary. We show the existence of at least three weak solutions under some hypotheses on given functions and the values of parameters.  相似文献   
90.
The μ-PD method originally developed for oxide crystals has been modified and applied for filamentary silicon crystal growth. Our main modification of μ-PD method is concerned with an arrangement of melt permeable feeder which is inserted into the nozzle. The feeder finishes by a sharp tip the diameter of which (is almost the same as that of the desired semiconductor fiber, i.e., less than 150 μm. Silicon fibers were grown from the small liquid pool at the end of the feeder. Three types of crucible-die arrangement were designed and tested. The best results were obtained with the help of inclined insert made of graphite fibers because of its ability to quench oscillations and longer operation life. Fiber crystals, 100 μm in diameter and 70 mm in length, have been grown successfully. Small meniscus stability, operating limits of μ-PD method and silicon carbide formation during the growth process are discussed.  相似文献   
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