The first catalytic asymmetric Fischer indolization is reported. In the presence of a 5 mol % loading of a novel spirocyclic chiral phosphoric acid, 4-substituted cyclohexanone-derived phenylhydrazones undergo a highly enantioselective indolization. Efficient catalyst turnover was achieved by the addition of a weakly acidic cation exchange resin, which removes the generated ammonia. The reactio...

Various organic solutions are used in many industries such as the petrochemical industry. The presence of moisture in those solvents results in poor insulation, corrosion of apparatus and catalyst poisoning. Therefore, the moisture content of the solvents must be reduced to less than several ppm. Since ion exchange resins have an ability to adsorb selectively polar substances fromnonpolar solve...

An improved method is described for the separation of 22 compounds normally related to purine and 6-thiopurine metabolism in biological materials using high-pressure liquid cation-exchange chromatography on strongly acidic exchange resin. The column (0.8 X 100 cm) is eluted with 0.4 M ammonium formate, pH 4.6, at a linear flow velocity of 5.2 cm.min--1 at 50 degrees C. The elution volumes of su...

C. F. MILLS I956 3. The organic complexes of copper in these extracts appeared to be stable in the presence of a cation-exchange resin after in vitro incubation at pH values above 2-5. Below pH 2-0 decomposition of complexes was appreciable. I wish to thank Dr J. Duckworth for his interest and encouragement and Dr R. L. M. Synge for advice on electrodialysis techniques. Thanks are due to Miss G...

Powell (1953) introduced a method for the estimation of serum calcium using the EEL flame photometer, and claimed that it gave results in good agreement with a standard titrimetric procedure. In this laboratory, both these methods were found to give low results when tested against standard sera, prepared by adding known amounts of calcium to serum completely decalcified by treatment with a cati...

We evaluated the use of ion-exclusion chromatographic systems for analyzing the behavior of inorganic ions (e.g., bicarbonate, sulfate, chloride, nitrate, phosphate, dissolved silicate, sodium, ammonium, potassium, magnesium, and calcium ions) in a suburban river located in Jakarta, Indonesia. Carbonate, phosphate, and silicate ion concentrations were determined using ion-exclusion chromatograp...

al.(12), I did not find the technique 12. Merlini J, Piro P, Pavesi F, et al. weakly basic resin Amberlite IRA-68 susceptible to technical artefacts. Detection and identification of monoclo(Rohm and Haas), which has a polyImmunofixation on cellulose acenal components: Immunoelectrophoreacrylic matrix, has practically no affintate deserves wider use for identifisis on agarose gel and immunofixat...

Combined ion-exclusion and cation-exchange chromatography (IEC/CEC) on a weakly acidic cation-exchange resin in the H-form (TSKgel Super IC-A/C) has been used as an advanced method for evaluation of the photooxidation of ionic nitrogen compounds, for example triethanolamine, trimethylamine, and urea, on a TiO2 photocatalyst. Formation of NH4 and NO3 from each nitrogen compound by photooxidation...