A practical method for synthesis of stable phosphorus ylides in aqueous media

A convenient one-pot synthesis of stable phosphorus ylides by the condensation of triphenylphosphine with dialkyl acetylenedicarboxylate and CH acids, such as penta-2,4-dione or diethyl propane-1,3-dioate, in the presence of -cyclodextrin as a catalyst (to increase the solubility of the reactants in water) without using toxic organic solvents was proposed. This methodology is of interest due to the use of water as a solvent, thus minimizing such factors as the cost, operational hazards, and environmental pollution.     

Combinatorial Aspects of Total Weight Orders over Monomials of Fixed Degree

Among all the restrictions of weight orders to the subsets of monomials with a fixed degree, we consider those that yield a total order. Furthermore, we assume that each weight vector consists of an increasing tuple of weights. Every restriction, which is shown to be achieved by some monomial order, is interpreted as a suitable linearization of the poset arising by the intersection of all the weight orders. In the case of three variables, an enumeration is provided. For a higher number of variables, we show a necessary condition for obtaining such restrictions, using deducibility rules applied to homogeneous inequalities. The logarithmic version of this approach is deeply related to classical results of Farkas type, on systems of linear inequalities. Finally, we analyze the linearizations determined by sequences of prime numbers and provide some connections with topics in arithmetic.     

Affinity Capillary Electrophoresis Studies on the Influence of Alcohols on the Interaction of β-Cyclodextrin with Non-Steroidal Anti-Inflammatory Drugs

Summary The influences of methanol, ethanol, 1-propanol and 1-butanol on the binding constants of -cyclodextrin (-CD) with non-steroidal anti-inflammatory drugs such as acemetacin, indometacin, cinmetacin, sulindac and diclofenac sodium and the separation of these drugs were studied by affinity capillary electrophoresis. No obvious effect was observable upon addition of methanol up to 6% (v/v) in the running buffer, while the addition of other alcohols at the concentration of 2% resulted in obvious decrease in the binding constants of -CD with acemetacin, indometacin, cinmetacin and sulindac. With an increasing chain length of added alcohols, all of these changes increased. Upon additions of different alcohols in the running buffer the change of the binding constant of -CD with diclofenac sodium was inconspicuous. Based on these results, the separation conditions for these drugs were optimized. The presence of 6% methanol in the running buffer containing 3 mM -CD was helpful to the baseline separation of these drugs. The electrophorograms of these drugs in the presence of ethanol, 1-propanol and 1-butanol showed a worse separation due to the decrease in the binding constants. The methods for the separation of these drugs and the study on the binding constants possess the advantages of easy performance, high speed and low sample consumption. AcknowledgementThe authors gratefully acknowledge the financial support from the National Natural Science Foundation of China (No.20275017), the Science Foundation of Jiangsu (No.BS2001063) and the Key Project of Cancer Institute of Jiangsu Province.     

(EC + β<Superscript>+</Superscript>) decays of the 11/2<Superscript>-</Superscript> isomer and 1/2<Superscript>+</Superscript> ground state of <Superscript>143</Superscript>Dy

The 1/2⁺ ground state and a 11/2^- isomer of very neutron-deficient isotope ¹⁴³Dy were produced by irradiation of an enriched target of ¹⁰⁶Cd with ⁴⁰Ca and studied by using a helium-jet fast tape-transport system in combination with proton-γ, X-γ and γ-γ coincidence measurements. A simple ( EC + β⁺) decay scheme of ^143mDy with a half-life of 3.0(3) s and a tentative ( EC + β⁺) decay scheme of ^143gDy with a half-life of 5.6(10) s are proposed. As a by-product, the 347- and 545-keV γ transitions in ¹³⁸Sm following the β-delayed proton emission of ¹³⁹Gd decay and the 323-keV γ transition in ¹³⁹Eu following the β-delayed proton emission of ¹⁴⁰Tb decay could be observed for the first time. Received: 20 August 2002 / Accepted: 28 October 2002 / Published online: 11 February 2003 RID="a" ID="a"e-mail: xsw@ns.lzb.ac.cn Communicated by D. Schwalm     

A new measurement of 208Tl levels

A new determination for the levels of the nucleus ²⁰⁸Tl was performed by measuring the γ-rays following the β^--decay of ²⁰⁸Hg. Twenty-six γ-rays were assigned and three new levels of ²⁰⁸Tl at 1.728 MeV, 1.652 MeV and 1.362 MeV have been affirmed. A partial ²⁰⁸Hg decaying γ scheme was proposed. The experimental level structure was compared with a shell model calculation. Received: 12 August 2002 / Accepted: 19 December 2002 / Published online: 25 February 2003 RID="a" ID="a"e-mail: Li41zhang@yahoo.com Communicated by W. Henning     

Phenyliodonium Derivatives of N-Heterocycles and CH-Acids, Their Synthesis, and Their Use in the Chemistry of Heterocycles. (Review)

The reactions of iodosylbenzene with CH-acids, including -dicarbonyl and N-heterocyclic compounds in the presence of alkali, which lead to the aryliodonium ylides (betaines) used in the synthesis of new derivatives of heterocycles, are examined. Both -dicarbonyl compounds and the anions of various heterocyclic compounds (pyrrole, indole, pyrazolidinedione, hydroxypyrones, hydroxypyridones, oxo- and dioxopyrimidines) and -keto sulfones, -disulfones, cyclopentadienes, and malononitrile enter into the reaction.     

Conditions for the Heterocyclization of O-Aroyl-β-morpholinopropioamide Oximes to 5-Aryl-3-(β-morpholino)ethyl-1,2,4-oxadiazoles

A search has been made for the conditions of heterocyclization of O-aroyl--morpholinopropioamide oximes to 5-aryl-3-(-morpholino)ethyl-1,2,4-oxadiazoles. We have investigated the heating of the starting compounds above their melting point, at their melting point, and holding in polar solvents (DMSO and DMF). Heating the O-aroylamide oxime hydrochlorides in DMF appeared optimal.     

A Special Basis of the Space of Meromorphic Sections on Riemann Surfaces

A special choice of basis for meromorphic sections of line bundles, in which all poles lie at the punctures, allows the decomposition of field operators (which are sections of bundles) into modes analogous to the standard decomposition on the sphere. Many of the calculational techniques used on the sphere can be reproduced for higher genus surfaces in this basis.Using this technique, in this paper, we compute a basis of K (the space of meromorphic sections on a Riemann surface, holomorphic away from two fixed points). This basis consists of the sections which have the expected zero or pole order at the two points.AMS Subject Classification (1991): 14H55