Curtis method

A -Methylethylcnediaminc, a mixed primary and secondary amine, also was used in these reactions. The products were similar except two of the ring nitrogen atoms were substituted by methyl groups (Makino et al., 1979 Mi-yamura et al., 1986, 1987). The Curtis method can produce different op-... 

Curtis Method. McQain et al. [467] report that polymers are generated by FdQ2-catalyzed dehalogenation polycondensation of 2,5-bis(chloromercurio)-3-alkylthiophenes with Cu powder in pyridine (Fig. 15). Ester hmctional groups at the 3-position do not seem to be affected by the polymerization conditions. 

A more general synthesis of selenophene derivatives, starting from diacetylenes and sodium hydrogen selenide, was investigated by Curtis.48 In the synthesis of new tetraphenylporphyrin molecules containing heteroatoms other than nitrogen, Ulman et al.49 used in principle the method of Curtis for the synthesis of the starting material (17). 

The coals used were PSOC 1098 Illinois 6 and Beulah-Zap North Dakota lignite from the Argonne coal bank. The analytical data of these coals are shown in Table I. The ratio of catalyst to coal was approximately 0.6 mmoles of metal per gram of coal. The organometallic catalysts were molybdenum(II) acetate dimer, Mo2(OAc)4, obtained from Strem, molybdenum(II) allyl dimer Mo2(OAc)4, was prepared by die method of Cotton and Pipal (25). The NiMo supported catalyst was prepared by addition of bis(l,5-cyclooctadiene) Ni(0) (Strem) to sulfided Mo on alumina (. Cp2Mo2( l-SH)2(p.-S)2, referred to as MoS2(OM), was prepared by modification of method of Dubois et al. (26), and Cp2Mo2Co2( i3-S)2(li4-S)(CO)4, CoMo(OM) was prepared by the method of Curtis et al. (27). Pentacarbonyl iron was obtained from Aldrich,... 

Curtis A (1989) Method UK Patent Application, N 8901759.4 Cutmore N, Eberhard M www.min-eng.com/protected/me02ex Czaja M, Mazurakb Z (1994) Optical Materials 3 95-98 Czaja M (1999) Excited States of Transition Elements, Duszniki Zdroj, Poland, Abstracts, Polish Academy of Science, P09 Davies G (1994) Properties and Growth of Diamonds. Gordon Davies, King s College, London... 

For a review of this and related reactions, see Screttas Steele Org. Prep. Proced. Int. 1990, 22, 271-314. LeBel Cherluck Curtis Synthesis 1973, 678. For another method, see Einhorn Luche Tetrahedron Lett. 1986, 27. 501. 

Evernden, J.F., Curtis, G.H., Obradovich, J. and Kistler, R., 1961. On the evaluation of glauconite and illite for dating sedimentary rocks by the potassium-argon method. Geochim. Cosmochim. Acta, 23 78-99. 

Aquatic microcosms and mesocosms offer the ideal situation to investigate populations of species interacting in their natural environment (i.e., to study communities stressed in structured systems see Section 4.5.1). It is, however, only recently that these experiments have been analyzed at the community level (Van Wijngaarden et al. 1995 Sparks et al. 1999 van den Brink and Ter Braak 1999). Until 10 years ago, experiments were evaluated at the population level, largely ignoring species interactions and energy flows in the systems. The development of community-level endpoints offered the possibility to evaluate the experiments on a community level (i.e., they offered the opportunity to scale up the level of evaluation Kedwards et al. 1999). Summary community-level endpoints calculated from the results of these experiments are mostly structural ones measures of diversity (e.g. numbers of species, and the Shannon-Weaver diversity index) and similarity of the treated systems compared to the untreated controls (e.g., the principal response curves method, Bray-Curtis dissimilarity, or Stander s index see van den Brink and Ter Braak 1998 for a comparison). 

Giant axons from squid have a large diameter ranging from 300 to 700 ym. Because of this large size, we are able to insert metal electrodes directly into the axon and measure capacitance and conductance across the membrane. This is the most unequivocal method to measure transmembrane capacitance and is far better than the use of external electrodes as done previously by Cole and Curtis (11). In spite of the simplicity and ease of this technique, there are still a few unsolved problems which will be discussed later. Figure 3 shows one of the exemplary results of nerve membrane capacitance and conductance measurements. Comparison of this result with the one shown in Figure 2 readily demonstrates that there are considerable differences between these two sets of curves. 

Curtis, D.R. Microelectrophoresis. In Physical Techniques in Biological Research. Vol. V. Electro-physiological Methods. Part A. pp. 144-190. Academic Press, New York 1964. 

Metal ion template mediation in macrocyclic synthesis has been a part of the field since its inception, its importance having been realized early in the development of this area. Two specific roles for the metal ion in template reactions have been proposed. These are, in turn, kinetic and thermodynamic in origin." In the kinetic template effect, the arrangement of ligands already coordinated to the metal ion provides control in a subsequent condensation during which the macrocycle is formed. The thermodynamic effect serves to promote stabilization of a structure which would not be favored in the absence of a metal ion. Schiff base condensations tend to be dependent on this latter type of template effect. Some of the more routine and general synthetic procedures will be described here. A more in-depth treatment can be found in a review by Curtis, with particular emphasis on general methods as well as modifications of preformed macrocycles." ... 

Cyanogen bromide, triazine method, cychc trani-2,3-carbonate reaction, carbonylation, periodate oxidation, epoxide activation Curtis azide rearrangement, coupling reagent method, acid anhydride reaction Schiff base formation reaction... 

FIGURE 3.14 Schematic representation of (a) Curtis azide activation and (b) coupling reagents activation method. 

A combination of methods (1) and (2) may be used, as in the Curtis machine which may have, say, five pressure stages with two moving wheels in each pressure stage. This leads to peripheral speeds as low as those of pressure turbines, along with high efficiency. 

Ein weiterer Weg fur die Racemat-Auflosung besteht nach Curti und Colombo (13) in der Tailor-Made-Methode , d.h. ein optischer Antipode wird bci dcr Kieselgelfallung inkorporiert und wieder ausgcwaschen, wonach das Gel selektiv aufnahmefahig wird. Vgl. auch Reed und Rogers (50). 

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