E. M. Pudovik

Optimization of Regional Passenger Bus Traffic Network

Abstract An approach to solving of optimization problems of inter-municipal passenger bus transportation routes network based on the development of a regional standard of service quality and the system of principles of its designing is proposed. A model of passenger traffic is discussed. Defining of network is based on the formation of a feasible set of route variants with choosing their optimal combination. The method and the indicators for quality rating of a route network are proposed.

Pyridoxal-derived Schiff’s bases

Over the past few decades synthesis of functionalized derivatives of pyridoxal (vitamin B6) and study of their biological activity have received a great deal of interest [1–3]. Among these compounds, monoand bis-azomethines of pyridoxal occupy an important place [4–6]. In practice, pyridoxal hydrochloride is often used since free pyridoxal is unstable and undergoes irreversible fast transformation.

Synthesis of aminofuropyridines via the reaction of aminosilanes with pyridoxal

We studied a possibility of modifying pyridoxal using aminosilanes and silazanes. The reactions of aliphatic and aromatic aldehydes with aminosilanes and silylamides of carboxylic acids occurred via attachment of the carbonyl reagent at the Si–N bond to form the corresponding trimethylsiloxy derivatives. In these reactions zinc chloride, lithium perchlorate, ptoluenesulfonic acid, and trimethylsilyl triflate were used as catalysts [4–9]. Depending on the reaction conditions, the interaction of aminosilanes with α,βunsaturated aldehydes resulted in 1,3-bis(dialkylamino)alkenes or the corresponding aminals [10, 11].

Interregional Logistic Center as the Growth Point of Regional Economics

Abstract The impact of large-scale logistics center (LC), which carries out integrated logistics (information, storage and transport) services at the organization of full-transport control, on the development of regional economy is analyzed. Problems of relationship of changes in the organization of transport environment of region and increase of efficiency of its economy by increasing budget revenues as a result of the performance of large-scale logistics center, and constructing on this basis new service industries are investigated. Authors assess prospects of influence of Sviyazhsky interregional logistics center on the economic development of Tatar Republic, and increase of competitiveness of its economy, taking into account service of international transit traffic “Western Europe - Western East”, “Northern Europe - Countries of the Middle East” which is accomplished by this LC.

Phosphorus-containing Schiff bases and 3,1-benzoxazines

In recent time, syntheses of coordination compounds derived from Schiff bases containing a hydroxy group and various metals, including biologically important ones [Zn(II), Cu(II), Cd(II), Co(II), Ni(II), Fe(III), Pd(II), Zr(IV), U(II), etc.], were reported. These complexes were shown to catalyze enantioselective epoxidation of non-functionalized olefins and allylic alcohols [1–4], act as chemosensors for aluminum ions [5], and possess magnetic properties [6]. Some Schiff bases and their metal complexes exhibited high fungicidal, antibacterial, and antimicrobial activity [7, 8]. On the other hand, there are no published data on O-phosphorylated Schiff bases which are undoubtedly of interest as ligands for metal complexes. In order to obtain Schiff bases containing different structural fragments, we selected O-phosphorylated salicylaldehyde 1 as starting compound. Compound 1 was synthesized by reaction of salicylaldehyde with 2-chloro-5,5-dimethyl-1,3,2λ-dioxaphosphinane 2-sulfide in the presence of a base and was brought into reactions with 2-aminophenol and 2-aminobenzyl alcohol. The reaction of 1 with 2-aminophenol gave Schiff base 2 which was readily phosphorylated at the phenolic hydroxy group with diphenylphosphinothioic chloride to afford bis-phosphorylated Schiff base 3 which may be regarded as a novel tridentate ligand (Scheme 1).

Phosphorus-containing salts derived from pyridoxal

Pyridoxal in the form of pyridoxal 5′-phosphate (vitamin B6) plays an important role in biochemical processes from protozoa to humans [1–3]. Pyridoxal is a cofactor for decarboxylation [4], amino acid racemization [5–7], transamination of α-keto acids, etc. [8–10]. Since the discovery of vitamin B6, the structure of pyridoxal has long remained not clearly understood. It reacts as aldehyde with primary amines to give Schiff bases, whereas its H NMR spectra in different solvents indicate its hemiacetal structure. For example, it was shown in [11, 12] that pyridoxal hydrochloride in alcoholic solution is converted into the corresponding monoalkyl acetal. In this communication we report on the reaction of “free” pyridoxal with phosphorous acid in alcoholic medium. We have found no published data on the formation of salt structures by pyridine or its derivatives with phosphorous acid. The reactions of equimolar amounts of pyridoxal (1) and phosphorous acid in alkanols led to the formation of crystalline compounds 2a–2e with sharp melting points. The structure of 2a–2e was determined on the basis of IR, H and P NMR, and MALDI mass spectra, elemental analyses, and X-ray diffraction data. The P NMR spectra of 2a–2e contained a signal at δP 0.90–2.50 ppm (JPH = 627–631 Hz), unambiguously indicating the presence of a phosphonate moiety. According to the H NMR spectra, molecules of 2a–2e contained an alkoxy group of the corresponding alcohol. Methylene protons of the former 5-CH2 group resonated as two doublets with a coupling constant of 13.1–13.3 Hz, and the acetal proton appeared as a singlet. The signal from the CH proton neighboring to the pyridine nitrogen atom was slightly displaced downfield, but the downfield shift was smaller than that observed in going from pyridoxal to pyridoxal hydrochloride. The OH proton in all compounds 2a–2e gave rise to a broadened singlet. The IR spectra of 2a– 2e displayed a series of absorption bands in the region 1800–2500 cm, which are typical of N–H group. These findings allowed us to presume that the products are furopyridine derivatives possessing an iminium nitrogen atom; this is indirectly supported by the good solubility of 2a–2e in water. According to the X-ray diffraction data, compounds 2a and 2b crystallize in monoclinic (P21/n) and triclinic (P-1) crystal systems, respectively. The independent part of a unit cell contains two independent furopyridinium cations and two H2PO3 counterions. The five-membered heterocycles in both molecules have O-envelope conformation. The alkoxy group occupies the axial position. Analysis of intermolecular interactions revealed formation of

Phosphorus-containing bisazomethines based on terephthalic aldehyde as tetradentate ligand of new type

Recently, hydroxyl-containing bisazomethines and complexes based on them attract a great interest. A wide range of metals including biogenic Zn(II), Cu(II), Cd(II), Co(II), Ni(II), Fe(III), Pd(II), Zr(IV), U(II) was used to obtain metal complexes catalyzing enantioselective epoxidation of unsubstituted olefins [1, 2], selective ortho-hydroxylation of phenols [3], epoxidation of styrene [4], oxidation of styrene to carbonyl compounds under the action of hydrogen peroxide [5], oxidation of alcohols to carbonyl compounds [6], oxidation of organic sulfides to sulfoxides [7], heterogeneous hydrogenation of alkenes and alkynes [8], butadiene polymerization [9]. Some of metal complexes showed high fungicidal, antibacterial, antimicrobial, anticancer activity [10–15].

1-Alkoxy-7-hydroxy-1,3-dihydrofuro[3,4- c ]pyridinium Salts

New salt structures have been synthesized from pyridoxal and various organic and inorganic acids.

Azomethines Based on Pyridoxal-Derived Aromatic Aldehydes

The reaction of pyridoxal with 2,4-dihydroxybenzaldehyde in a hydrochloric acid solution gave 1-(5-formyl-2,4-dihydroxyphenyl)-7-hydroxy-6-methyl-1,3-dihydrofuro[3,4-c]pyridin-5-ium chloride. Treatment of the latter with sodium hydride in ethanol afforded a free aldehyde in 85% yield. A series of azomethines and imidazolidines was obtained by reacting the obtained aldehyde with various amines and diamines.

Reactions of pyridoxal with aromatic carboxylic acids in alcoholic medium

Reactions of pyridoxal with benzoic acid and its derivatives in alcoholic medium afforded alkoxyfuropyridinium salts with potential biological activity.