ipso‐Substitution Reaction in the Convergent Stepwise Synthesis of Calix[8]arene with Regioselectively Functionalized Upper Rim

The acid‐catalyzed multi‐step synthesis of calix[8]arene 1 , which contains a regioselectively functionalized upper rim, has been investigated through the careful separation of the resulting by‐products. A total of 11 types of cyclic and acyclic by‐products were isolated and identified by spectral and microanalytical data. Semiempirical molecular‐orbital calculations demonstrated that the synthetic process involves two types of reaction mechanism, one of which leads to the favorably constructed framework, while the other results in undesirable fragmentation reactions via ipso‐substitution. A comparison of the theoretical predictions and the observed by‐products revealed that steric hindrance, as well as the regioselectivity of the reaction, is also an important factor for determining the reaction pathway. A possible rationale is presented to explain the overall formation process leading to calix[8]arene 1 along with the by‐products.     

Application of Phosphonium Salts to the Reactions of Various Kinds of Amides

The phosphonium salts 1 and 2 prepared from triphenylphosphine and N‐halogenosuccinimide proved to be applicable to the conversion of amide compounds. Especially, halogenation of electron‐deficient heteroaromatic alcohols with these reagents seems to be a convenient method compared to the halogenation with phosphorus oxyhalides.     

Novel Reactive Polymers Containing Hemiacetal Ester and Vinyl Moieties: Synthesis and Selective Polymerization of 1‐Methoxyallyl Methacrylate Derived from Methacrylic Acid and Methoxyallene

A novel functional monomer, 1‐methoxyallyl methacrylate (MOAMA), was prepared and its polymerization behavior was investigated. The radical polymerization of MOAMA led to a polymeric network due to the participation of the allyl group in the reaction. Contrarily, anionic polymerization proceeded in a living fashion to yield linear poly(MOAMA) without gelation. Since both the network‐type and linear polymers possess hemiacetal ester and vinyl moieties, the two‐fold polymerization behavior of MOAMA represents a new pathway towards reactive polymers.     

Arsenic species in terrestrial fungi and lichens from Yellowknife,NWT, Canada

Levels of total arsenic and arsenic species were determined in fungi collected from Yellowknife, NWT, Canada, an area that has been affected by past mining activities and elevated arsenic levels. Lichens (belonging to Cladonia and Cladina genera), as well as the mushrooms Coprinus comatus, Paxillus involutus, Psathyrella candolleana and Leccinum scabrum, were studied for the first time. Most of the fungi contained elevated arsenic levels with respect to data found in the literature for background levels. Minor amounts of arsenobetaine were found in all lichen samples. The major water‐soluble arsenic species in the fungi were inorganic arsenic for lichens and Psathyrella candolleana, arsenobetaine for Lycoperdon pyriforme and Coprinus comatus, and dimethylarsenate for Paxillus involutus and Leccinum scabrum. A large proportion of water‐soluble arsenic in Paxillus involutus occurred as an unknown compound, which did not co‐chromatograph with any of the available standard arsenic compounds. Low proportions of water‐soluble arsenic species (made evident by low extraction efficiencies) were observed in the majority of fungi studied. Arsenic that is not extracted may be bound to lipids, cell components or proteins, or might exist on the surface of the fungus as minerals. Copyright © 2000 John Wiley & Sons, Ltd.     

Investigation of a possible abrupt change in structure atN = 58–60 using two-proton transfer

The (¹⁴C,¹⁶O) reaction on Cd isotopes has been investigated at an energy of 60 MeV. Relative spectroscopic strengths to the ground states are found to decrease nearN=60.     

Vertex‐disjoint cycles containing specified vertices in a bipartite graph

A minimum degree condition is given for a bipartite graph to contain a 2‐factor each component of which contains a previously specified vertex. © 2004 Wiley Periodicals, Inc. J Graph Theory 46: 145–166, 2004     

Laser induced fluorescence of HNO and DNO ã1A″ — -X1A′ in a supersonic free jet

The SRVL fluorescenee lifetimes and fluorescence excitation spectra of the HNO ã¹A″ -X¹AA′ transition were measured in a supersonic free jet. The cooling of a rotational temperature in the jet made it possible to clear up the parity-selected perturbations in the asymmetric rotor under higher resolution condition. The fluorescence lifetimes of strongly perturbed levels, i.e. HNO ã¹A″ 011 rovibronic levels were observed with dual exponential decay profiles, while non-perturbed levels exhibited single ones. The SRVL fluorescence lifetimes and fluorescence excitation spectra of DNO ã¹″ -X¹A′ were measured under the same condition as HNO. The rotationll analysis of the DNO ã¹A″ 011 rovibronic levels was first carried out in the jet.     

Duality involving the mock theta function f(q)

We show that the coefficients of Ramanujan's mock theta functionf(q) are the first non-trivial coefficients of a canonical sequenceof modular forms. This fact follows from a duality which equatescoefficients of the holomorphic projections of certain weight1/2 Maass forms with coefficients of certain weight 3/2 modularforms. This work depends on the theory of Poincaré series,and a modification of an argument of Goldfeld and Sarnak onKloosterman–Selberg zeta functions.     

A novel chip device based on wired capillary packed with high performance polymer-based monolith for HPLC: reproducibility in preparation processes to obtain long columns.

This report describes the development of novel wired chip devices for mu-HPLC analyses. The monolithic capillary column to be wired was prepared using a tri-functional epoxy monomer, tris(2,3-epoxypropyl)isocyanurate with a diamine, 4-[(4-aminocyclohexyl)methyl]cyclohexylamine. The prepared column was evaluated by SEM observation of the sectional structure of column and micro-HPLC. In addition, the reproducibility in the preparation of long capillary columns having nearly 1 m length was extensively examined for applications of novel wired chip devices. The authors demonstrated that the monolithic structure of the prepared long capillary could be finely controlled under the strictly maintained operational conditions and thus the relative standard deviation (RSD) of the column properties such as the number of theoretical plates, retention factor, and permeability could be well controlled to become less than 10%. Furthermore, the wired chip device column showed that its high performance was kept even after chip preparation.