Oxidation reactions of indapamide. A novel route to the indole derivative,N-(3-sulfamyl-4-chlorobenzamido)-2-methylindole

Indapamide ( 1 ) is readily oxidized with mild oxidizing agents to the indole derivative 2 . Dehydrogenation of indapamide is a convenient one step synthesis of a complex indole compound.     

Some novel halogenated phenazine derivatives

3-Amino-10-aryl-2-arylimino-2,10-dihydrophenazines 1 undergo iodination in the 4-position of the phenazine nucleus yielding compounds which are identical with those obtained by oxidation of appropriate N-aryl-o-phenylenediamines with sodium iodate in the presence of acid. Bromination also takes place in this position but a second bromine atom enters the para-position of the arylimino moiety. The isomeric 10-aryl-3-aryl-amino-2,10-dihydro-2-iminophenazines 2 yield unstable iodo-derivatives but undergo bromination in the 1-and 4-position of the phenazine nucléus and in the ortho- and para-positions of the arylamino substituent. Preliminary chlorination experiments indicate that the substitution pattern is analogous to that established for the brominated products. The removal of bromine and iodine from the phenazine ring by reaction with a primary or secondary amine and their replacement by hydrogen rather than by the amine residue is also recorded.     

The first organically templated thorium compounds, [C4N2H12]0.5[ThF5] and [C5N2H14][ThF6].0.5H2O

Organically templated thorium compounds were synthesized for the first time under hydrothermal conditions; the piperazine containing compound consists of 2-D layers, while the 2-methylpiperazine phase contains unprecedented 1-D chains of face-sharing ThF9 polyhedra.     

Pentalene complexes of group 7 metal carbonyls: an organometallic mixed-valence system with very large metal-metal electronic coupling

The bimetallic complexes [M(CO)(3)](2)(mu:eta(5):eta(5)-Pn) (Pn = pentalene, C(8)H(6); M = Mn, Re) have been synthesized and characterized crystallographically; the Mn compound was isolated as solely the anti-isomer, while the Re analogue was formed as a mixture of anti- and syn-isomers. [Mn(CO)(3)](2)(mu:eta(5):eta(5)-Pn) may be reduced chemically to its mono- and dianions; the mixed-valence Mn(I)/Mn(0) monoanion is shown by ESR, vibrational, and electronic spectroscopies to be a Robin-Day class III system with an exceptionally large electronic coupling between the metal centers.     

Progress in the realisation of an autonomous environmental monitoring device for ammonia

Progress in the development of a micro-fluidic system for colorimetric monitoring of ammonia in drinking and wastewater is described. The ultimate goal is to have a miniaturised instrument that can produce accurate, reliable measurements, is easy to operate, has minimal power consumption, and can operate autonomously for a year. In this study, the indophenol reaction is incorporated into a simple, reliable analytical micro-fluidic system. Absorbance measurements for the blue ammonia-indophenol complex formed in the micro-fluidic system are shown. A key issue is the limiting stability of hypochlorite, a reagent used in the assay. The effects of hypochlorite concentration and impurities on the stability of hypochlorite are investigated and discussed. Decomposition is shown to be very dependent on the presence of heavy-metal impurities. With low levels of these catalytic metals and careful storage, hypochlorite has been shown to be stable for over a year.     

Controlled structural variations in templated uranium sulfates

A series of experiments in the UO(2)(CH(3)CO(2))(2).2H(2)O/H(2)SO(4)/1-(2-aminoethyl)piperazine/H(2)O system were conducted to determine the effects of variation in initial reactant concentrations on the reaction products. Several reaction gels were produced, in which the composition varied from 16:80:4:500 UO(2)(CH(3)CO(2))(2).2H(2)O/H(2)SO(4)/1-(2-aminoethyl)piperazine/H(2)O to 4:92:4:500 UO(2)(CH(3)CO(2))(2).2H(2)O/H(2)SO(4)/1-(2-aminoethyl)piperazine/H(2)O. Single crystals of two new organically templated uranium sulfates, [N(3)C(6)H(18)](2)[(UO(2))(5)(H(2)O)(SO(4))(8)].5H(2)O and [N(3)C(6)H(18)][(UO(2))(2)(H(2)O)(SO(4))(3)(HSO(4))].4.5H(2)O, were isolated. Both compounds exhibit structures in which the inorganic frameworks are two-dimensional and the protonated amines reside between layers, participating in extensive hydrogen bonding. The composition and structure of each compound is dependent on the nature of the starting concentrations. Crystal data: for [N(3)C(6)H(18)](2)[(UO(2))(5)(H(2)O)(SO(4))(8)].5H(2)O, monoclinic, space group P2(1)/n (No. 14), a = 21.5597(3) A, b = 10.2901(2) A, c = 22.8403(3) A, beta = 96.7436(7) degrees, and Z = 4; for [N(3)C(6)H(18)][(UO(2))(2)(H(2)O)(SO(4))(3)(HSO(4))].4.5H(2)O, monoclinic, space group P2(1)/a (No. 14), a = 15.7673(4) A, b = 10.5813(3) A, c = 16.7710(5) A, beta = 99.9216(9) degrees, and Z = 4.     

Characterisation of the ester-substituted products of the reaction of p-t-butyl calix[4]arene and ethyl bromoacetate using LC-UV-MS and LC-DAD

A series of derivatisation reactions between p-t-butyl calix[4]arene and ethyl bromoacetate were carried out in order to prepare 1,3 diester substituted calix[4]arene. Mass spectral data, obtained from direct injection of samples, indicated that the reactions were rich in the desired product. Since the ultra violet (UV) spectra of the desired product and possible impurities are very similar, liquid chromatography (LC) chromatographic data seemed to corroborate these results. However, when on-line LC-UV-MS was carried out and each LC peak subjected to MS analysis as it eluted, a very different picture emerged. It was found that many of these reactions actually contained high levels of the monoester product which, having less affinity for sodium in the MS, is therefore seriously underestimated in any direct injection assay. LC-diode array detection (DAD) methods were also used to help successfully identify and characterise the compounds being formed in these complex reactions. The overall results obtained in this paper allowed the optimal reaction conditions to be determined for this reaction. LC-MS analysis of the chromatographic peaks also identified the presence of two isomers of the diester substituted calix[4]arene (1,3 and 1,2 diesters). The combination of LC and UV/MS detection is required for accurate analysis of the products of such reactions.     

Perceptually motivated time-frequency analysis

This paper describes the design of a bilinear time-frequency distribution which is a joint model of temporal and spectral masking. The distribution is used to generate temporally evolving excitation patterns of nonstationary signals and systems and is conceived as a tool for acousticians and engineers for perceptual time-frequency analysis. Distribution time and frequency resolutions are controlled by a separable kernel consisting of a set of low-pass time and frequency smoothing windows. These windows are designed by adapting existing psychoacoustic models of auditory resolution, rather than using mathematical window functions. Cross-term interference and windowing clutter are highly suppressed for the distribution, ensuring resolution accuracy over a dynamic range sufficient to encompass that of the auditory system (in excess of 100 dB). Application to the analysis of a synthetic and two real signals are included to demonstrate the approach.     

CO2 laser microfabrication of an integrated polymer microfluidic manifold for the determination of phosphorus

A simple colorimetric technique is implemented in a polymer microfluidic manifold. The simple chemistry aids an uncomplicated microchannel design, which is fabricated by CO(2) laser ablation. Issues such as bonding of multiple layers, alignment of micro-fabricated structures and integration of optical components are addressed. A demonstration of a stopped flow regime in the microfluidic manifold is also presented.