Acylation of 2-methoxypropene with anhydrides and halides of perfluorocarboxylic acids in the presence of tertiary amines

3-Methoxy-1-(perfluoroalkyl)but-2-en-1-ones were synthesized byC-acylation of 2-methoxypropene with perfluorocarboxylic acid anhydrides, acid chlorides, and acid fluorides in the presence of tertiary amines. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1813–1815, September, 1999.     

5-Benzylidene- and 5-Aminomethyl-4-oxo-4,5,6,7-tetrahydroindazoles

The reaction of 3-methyl-4-oxo-4,5,6,7-tetrahydroindazoles with benzaldehydes gave 5-benzylidene-3-methyl-4-oxo-4,5,6,7-tetrahydroindazoles. Under Mannich conditions, 3-methyl-1-phenyl-4,5,6,7-tetrahydroindazole gave 5-aminomethyl-3-methyl-4-oxo-1-phenyl-4,5,6,7-tetrahydroindazoles.     

Composite Fibers Based on Chitin and Cellulose

Composite fibers were produced by mixing of chitin and cellulose solutions with subsequent molding from these solutions under standard conditions. The effect of composition of systems on the structural modification and the deformation-strength characteristics of the fibers was studied.     

Hydration Heats of Zeolites For Evaluation of Heat Exchangers

The enthalpy of hydration of purified clinoptilolite from Beli Plast, Bulgaria, and various cation-exchanged types such as Na-, K-, Ca- and Mg-clinoptilolite was determined by the adiabatic water-vapor absorption calorimeter. The hydration enthalpy becomes more exothermic in the sequence K, Na, Ca, Mg depending on hydration energy values of exchanged cations. Na-clinoptilolite would be an efficient heat exchanger in a wide temperature range of dehydration, 180–300°C, while Mg-clinoptilolite in higher temperatures, 300–350°C. This revised version was published online in July 2006 with corrections to the Cover Date.     

Sur l'histoire des démonstrations analytiques du théorème fondamental de l'algèbre

The first proof of the fundamental theorem of algebra, proposed by D'Alembert in 1746 and practically unknown to this day, stimulated a series of “analytic” proofs which made essential use of the properties of polynomials as analytic functions and placed the theorem within complex analysis. One of the simplest and most widely known modern proofs is formed from the “analytic” proofs of Gauss, Argand, Legendre and Cauchy, which used and developed the ideas of D'Alembert.