Research on isoalloxazine derivatives

A convenient route to 9-(-aminoethyl)isoalloxazines is offered, based on monoacetylethylenediamine. 6-Chloro-7-methyl-9-(-aminoethyl)-isoalloxazine is used to synthesize some acyl derivatives and azomethines, among them some with the bis(-chloroethyl)amino group, for biological testing.For Part II see [10].     

Time-resolved and steady state spectroscopy of polydisperse colloidal silver nanoparticle samples

A signal due to coherently excited vibrational motion has been observed in polydisperse silver nanoparticle samples. The particles were synthesized via a wet chemistry seed mediated method, which yields different particle shapes, including spheres, rods, and irregular triangular-shaped particles. The measured vibrational periods were compared to the results from continuum mechanics calculations. This analysis shows that the observed signal arises from the triangular-shaped particles, rather than the rods or spheres. The period of vibration increases as the dimensions of the triangular-shaped particles increase; specifically, we find that the period is given by 2h/c(l), where h is the bisector of the triangle and c(l) is the longitudinal speed of sound in silver.     

Reaction of 3H-perfluoroalk-2-enes with ammonia

3H-Perfluoroalk-2-enes react with aqueous ammonia to form polyfluorinated iminoenamines, from which hexafluoroacetylacetone and its analogs were synthesized.     

Comparative Study of Reactivity of Cellulose,Chitosan, and Chitin-Glucan Complex in Sulfoethylation

Sulfoethylation of the chitin-glucan complex, isolated from mycelium of the mold fungus Aspergillus niger, by substitution with sodium -chloroethylsulfonate or addition of sodium vinylsulfonate is examined. A comparative study is made of the reactivity of the chitin-glucan complex, chitosan, and cellulose in the both reactions. The sorption characteristics of the sulfoethylated products with respect to Cu(II) and Cr(III) are determined.     

Fluorescence of albumin solutions containing Pb2+ and Na+ ions

Solutions of bovine serum albumin with metal ions Pb²⁺ and Na⁺ were studied by fluorescence analysis in the visible and UV ranges in relation to such parameters of the medium as the concentration of macromolecules, the pH, and the ionic strength of the solution. The formation of nanoparticles, protein clusters, in aqueous solutions of albumin containing ions of such a heavy metal as lead was revealed by fluorescence polarization analysis. This investigation is of practical value for the solution of ecological and medical problems.     

Synthesis, morphology, and phase composition of manganese oxide obtained under exposure to external electric field

New method for obtaining highly dispersed manganese oxide under the action of a dc electric field was suggested. It was found that the electric field parameters affect the phase composition, shape, morphology and size of manganese oxide particles and the content of water. It is demonstrated that the manganese oxide synthesized can be used as a vulcanizing agent in manufacture of sealants based on thiocol and surpasses in application efficiency the analog produced by the conventional method.     

Investigation of oligomethylmethacrylate-lithium and its donor-acceptor complexes with organometal compounds by means of infrared spectroscopy

Anionic polymerization of methyl methacrylate in THF and toluene at ?70° was studied by means of i.r. spectroscopy. The reaction mixtures show characteristic absorption at 1600–1750 cm^?1 caused by the stretching vibrations of the propagating centre as well as by the groups obtained in side reactions (metal splitting, addition to a carbonyl group, cyclization). Sec-butyllithium is more effective in THF than n-butyllithium, ethyllithium and fluorenyllithium. When polymerizing in toluene, small amounts of a donor (THF or HMPT) cause formation of active centres similar to those in pure THF. The “living” ends of oligo-MMA form 1:1 complexes with electron acceptors such as trialkylaluminium and triethylboron.     

Synthesis of 5-fluoro-2,4,6-tris(perfluoroalkyl)pyrimidines

5-Fluoro-2,4,6-tris(perfluoroalkyl)pyrimidines were synthesized by reactions of polyfluorinated iminoenamines with perfluorocarboxylic acid anhydrides and perfluorobutanoyl chloride. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 11, pp. 2195–2196, November, 1999.