Synthesis and characterization of some anomeric pairs of per-O-acetylated aldohexopyranosyl cyanides (per-O-acetylated 2,6-anhydroheptononitriles). On the reaction of per-O-acetylaldohexopyranosyl bromides with mercuric cyanide in nitromethane

The synthesis and characterization of the anomeric pairs of the per-O-acetylaldohexopyranosyl cyanides of D-galactose, L-fucose, D-glucose, and D-mannose, as well as of 3,4,6-tri-O-acetyl-2-deoxy-2-phthalimido-beta-D-glucopyranosyl cyanide, are described. Cyanation of the readily available, per-O-acetylaldohexopyranosyl bromides with mercuric cyanide in nitromethane, and subsequent purification, gave the corresponding, crystalline glycosyl cyanides with a high degree of 1,2-trans stereoselectivity. Thus, per-O-acetylated aldohexopyranosyl cyanides of the 1,2-trans configuration were obtained in yields ranging from 20 to 79%, whereas the corresponding 1,2-cis anomers were obtained in yields of less than or equal to 8.4%, the ratios of the 1,2-trans:1,2-cis anomers so prepared being greater than or equal to 8.5:1. The principal by-products of these irreversible, cyanation reactions were the per-O-acetylated 1,2-O-[1-(exo- and endo-cyano)ethylidene]aldohexopyranoses, obtained in yields of up to 40%. The structural assignments of the per-O-acetylaldohexopyranosyl cyanides were unequivocally established by elemental analysis, chemical transformation, vibrational spectroscopy, and 13C- and 1H-nuclear magnetic resonance spectroscopy. Correlations between the physical properties and the anomeric configurations of these C-aldohexopyranosyl compounds are described.     

Improved and large-scale synthesis of certain glycosyl cyanides. Synthesis of 2,5-anhydro-5-thio-D-allononitrile

The first synthesis of 2,5-anhydro-5-thio-D-allononitrile starting with L-lyxose, via a trifluoromethanesulfonic ester intermediate, has been accomplished. Methods have been developed to achieve a large-scale synthesis of 3,4,5,7-tetra-O-acetyl-2,6-anhydro-D-glycero-D-talo-heptononitrile (5). An improved procedure has been developed to synthesize 2,5-anhydro-3,4,6-tri-O-benzoyl-D-gulononitrile (9). The structures of 5 and the thioamide derivative from 9, 2,5-anhydro-3,4,6-tri-O-benzoyl-D-gulonothioamide, were confirmed by X-ray crystallographic analysis.     

One-pot synthesis of per-O-acetylated thioglycosides from unprotected reducing sugars

A sequential per-O-acetylation and thioglycosidation of unprotected reducing sugars using a stoichiometric quantity of acetic anhydride and alkyl- or arylthiols is reported. These reactions, which are catalyzed by BF3.OEt2, together constitute an efficient one-pot method for the synthesis of acetylated thioglycosides.     

Residual disinfection of some preparations and substances.

The results of our experiments over many years point to the possibility of practical application of disinfectants of residual effect. In our opinion, further investigations should be carried out in the following two directions: detection of new means and preparations showing uniform properties and development of an optimum method of their application. We believe that residual disinfection will play a role in the prophylaxis of hospitalism.     

Improved confocal characterization of targets in nuclei of cytogenetic preparations

OBJECTIVE: To show that cellular preparations requiring depth analysis of different domains stained by molecular cytogenetic methods (fluorescence in situ hybridization and primed in situ) can be improved by regularized factor analysis of medical image sequences (FAMIS) to isolate fluorescent probes by means of intensity depth profiles of fluorochromes, to track relevant DNA sequences (cosmids and centromeres) in cell nuclei during interphase and to improve the use of cytogenetic techniques resulting in flat preparations of whole cells that are assumed to preserve probe access to their targets. STUDY DESIGN: 3D sequences of images obtained by depth displacement in a confocal microscope were first analyzed by the FAMIS algorithm, which provides factor curves. Factor images then resulted from regularization methods that improve signal/noise ratio while preserving target contours. RESULTS: Factor curves and regularized factor images helped analyze targets inside nuclei. CONCLUSION: It is possible to process preparations containing numerous spots (even when they are on different planes) to differentiate stained targets, to investigate depth differences and to improve visualization and detection.     

Isolation and some properties of colicin V preparations.

E. coli strain CLI(V) produces colicin V which can exist in two chemically different forms. A heat-stable, liposaccharide-protein complex is present as a main component of the cell wash. An intracellular colicin is a heat-labile and seems to be a simple protein. Preliminary experiments have shown that colicin V inhibits simultaneously synthesis of protein, RNA and DNA. Its mode of action is similar to colicins: E1, B, K and A.     

Anoxic-oxic activated-sludge of cyanides and phenols

The anoxic-oxic activated-sludge process has been evaluated in a laboratory investigation as a means for effective treatment of cyanide-laden wastewaters, with phenols used as the organic carbon sources for denitrification reactions. The performance of the process was evaluated at different levels of feed cyanide concentration and mean cell residence time (MCRT). The results obtained indicate that the phenolic compounds used can be effectively used as the organic carbon sources to promote denitrification reactions. The effects of cyanide inhibition on overall TOC removal can be alleviated at longer MCRTs. Between 1.2 and 2.2 g TOC can be utilized per gram NO(2) + NO(3) (-) -N removed in the anoxic chamber depending on the prevailing MCRT. Microbial oxidation of cyanide and thiocyanate which yields ammonia is the main mechanism responsible for the removal of cyanide and thiocyanate observed in the anoxic-oxic activated-sludge process. Excellent removal efficiencies have been observed with feed concentrations up to 60 mg CN(-)/L and 100 mg SCN(-)/L Frequent exposure of autotrophic and aerobic cyanideutilizing microbes does not impede their activities in the oxic environment. Good nitrification and denitrification efficiencies are attainable in the anoxic-oxic activated-sludge process in the presence of high feed cyanide and thiocyanate concentrations, provided that MCRT is maintained at a desirable level. As a result, the microbial degradation of cyanide and thiocyanate in conjunction with nitrification and denitrification to produce innocuous nitrogen gas is feasible in the anoxic-oxic activated-sludge process.     

Destruction of cyanogen bromide and inorganic cyanides

Cyanogen bromide in water and seven organic solvents and sodium cyanide in water may safely and efficiently (greater than 99.7%) be destroyed using sodium hydroxide (1 M) solution and commercially available sodium or calcium hypochlorite. Details are given of an analytical procedure which can be used to check the final reaction mixture for the presence of residual cyanogen bromide or cyanide.     

Improved stability of Drosophila larval neuromuscular preparations in haemolymph-like physiological solutions

Neuromuscular preparations from third instar larvae of Drosophila are not well-maintained in commonly used physiological solutions: vacuoles form in the muscle fibers, and membrane potential declines. These problems may result from the NaK ratio and total divalent cation content of these physiological solutions being quite different from those of haemolymph. Accordingly haemolymph-like solutions, based upon ion measurements of major cations, were developed and tested. Haemolymph-like solutions maintained the membrane potential at a relatively constant level, and prolonged the physiological life of the preparations. Synaptic transmission was well-maintained in haemolymph-like solutions, but the excitatory synaptic potentials had a slower time course and summated more effectively with repetitive stimulation, than in standard Drosophila solutions. Voltage-clamp experiments suggest that these effects are linked to more pronounced activation of muscle fiber membrane conductances in standard solutions, rather than to differences in passive muscle membrane properties or changes in postsynaptic receptor channel kinetics. Calcium dependence of transmitter release was steep in both standard and haemolymph-like solutions, but higher external calcium concentrations were required for a given level of release in haemolymph-like solutions. Thus, haemolymph-like solutions allow for prolonged, stable recording of synaptic transmission.Abbreviations HL haemolymph-like     

Molecular and crystal structures of N-(beta-D-galactopyranosyl)pyridinium bromide and its per-O-acetylated derivative

1H NMR spectroscopy and X-ray diffraction data are described for N-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)pyridinium bromide and N-(beta-D-galactopyranosyl)pyridinium bromide. X-ray crystallography revealed that the O-acetylated salt crystallizes with two molecules of water and one molecule of ethanol.     

Radiation-induced polymerization in dilute aqueous solutions of cyanides

It has been found that the addition polymerization of cyanides (HCN and NH₄CN) takes place in dilute, O₂-free irradiated aqueous solutions, in addition to the abundant formation of various smaller molecules. A polymer with a molecular mass of 16,000 amu was found. Its abundance increases with initial cyanide concentration and absorbed dose and can be up to 31% of the total amount of radiolytic products. HPLC data also indicate the presence of two more products at 22,000 amu and 10,000 amu, which are less abundant by one order of magnitude. The same molecular masses appear throughout the examined range of cyanide concentration (0.001–0.2 mol dm^–3) and absorbed dose (2–200 kGy). They remain also at large doses (up to 1250 kGy) after a complete destruction of cyanide.