A rapid,chromatography-free route to substituted acridine–isoalloxazine conjugates under microwave irradiation

Microwave irradiation was applied to a sequence of condensation reactions from readily available 9-chloroacridines to provide a range of novel acridine–isoalloxazine conjugates. The combination of these two moieties, both of biological interest, was achieved by a chromatography-free route.     

On the determination of the tidal amplitude in a river estuary having an irregular topography

A method based upon the balance of mechanical energy is used to calculate the local tidal amplitude in a river estuary. The technique permits the specification of an irregular topography and variable coefficient of eddy viscosity in the landward direction. Numerical calculations are performed for a river having the approximate dimensions of the Thames between Southend and Teddington. The fitting of the topography involves the specification of the mean width and depth by a suitable functional law along the river. The parametric representation of the turbulence may be quantified by prescribing that the local eddy viscosity be proportional to the local mean depth. The resulting evaluations are then used to assess the effect upon the tidal dynamics of nonuniformities in the topography and structure of the turbulence.     

The Synthesis of 4-Amino-2-methyl-3-(1-oxo) Pent-4-ynyl-5,6,7,8-tetrahydrobenzo[b]thieno[2,3-b]pyridine

The synthesis of ketone 1 from the ethyl ester of 4-amino-2-methyl-5,6,7,8-tetrahydrobenzo[b]thieno[2,3-b]pyridine-3-carboxylic acid using β-ketosulfone methodology is described.     

The ν2 and ν4 bands of AsH3

The infrared absorption of arsine, AsH₃, between 750 and 1200 cm^?1 has been recorded at a resolution of 0.006 cm^?1. Altogether 2419 transitions, including nearly 700 “perturbation allowed” transitions with Δ∥k ? l∥ = ±3, ±6, and ±9, have been assigned to the ν₂(A₁) and ν₄(E) bands. Splitting of the transitions for K″ = 3, 6, and 9 was also observed. To fit the rotational pattern of the v₂ = 1 and v₄ = 1 vibrational states up to J = 21, all the experimental data were analyzed simultaneously on the basis of a rovibrational Hamiltonian which took into account the Coriolis interaction between ν₂ and ν₄ and also included several essential resonances within them. The derived set of 38 significant spectroscopic parameters reproduced the 2328 transition wavenumbers retained in the final fit within the accuracy of the experimental measurements.     

A consistent RPA formalism

This paper examines the quasi-boson and generator-coordinate derivations of the RPA and concludes that they make uncritical and inconsistent use of the assumption that ground state correlations be small. It is proposed that consistent derivations of the RPA to various orders can be carried out by explicit retention of a certain power of a parameter γ which is proportional to the norm of the ground state correlations. To illustrate such a method, it is proved that a consistent, non-trivial, linear RPA theory exists only if the residual potential is small enough for first order perturbation theory to be valid.     

Identification of homemade inorganic explosives by ion chromatographic analysis of post-blast residues

Anions and cations of interest for the post-blast identification of homemade inorganic explosives were separated and detected by ion chromatographic (IC) methods. The ionic analytes used for identification of explosives in this study comprised 18 anions (acetate, benzoate, bromate, carbonate, chlorate, chloride, chlorite, chromate, cyanate, fluoride, formate, nitrate, nitrite, perchlorate, phosphate, sulfate, thiocyanate and thiosulfate) and 12 cations (ammonium, barium(II), calcium(II), chromium(III), ethylammonium, magnesium(II), manganese(II), methylammonium, potassium(I), sodium(I), strontium(II), and zinc(II)). Two IC separations are presented, using suppressed IC on a Dionex AS20 column with potassium hydroxide as eluent for anions, and non-suppressed IC for cations using a Dionex SCS 1 column with oxalic acid/acetonitrile as eluent. Conductivity detection was used in both cases. Detection limits for anions were in the range 2-27.4ppb, and for cations were in the range 13-115ppb. These methods allowed the explosive residue ions to be identified and separated from background ions likely to be present in the environment. Linearity (over a calibration range of 0.05-50ppm) was evaluated for both methods, with r(2) values ranging from 0.9889 to 1.000. Reproducibility over 10 consecutive injections of a 5ppm standard ranged from 0.01 to 0.22% relative standard deviation (RSD) for retention time and 0.29 to 2.16%RSD for peak area. The anion and cation separations were performed simultaneously by using two Dionex ICS-2000 chromatographs served by a single autoinjector. The efficacy of the developed methods was demonstrated by analysis of residue samples taken from witness plates and soils collected following the controlled detonation of a series of different inorganic homemade explosives. The results obtained were also confirmed by parallel analysis of the same samples by capillary electrophoresis (CE) with excellent agreement being obtained.