Zinc oxide nanorods with 100 nm diameter and 900 nm length were grown on the surface of a silver wire (0.25 mm in diameter) with the aim to produce electrochemical nanosensors. It is shown that the ZnO nanorods exhibit a -dependent electrochemical potentiometric behavior in an aqueous solution. The potential difference was found to be linear over a large logarithmic concentration range (1 M to 0.1 M) using Ag/AgCl as a reference electrode and the response time was less than one minute. In order to adapt the sensors for calcium ion measurements in biological fluids with sufficient selectivity and stability, plastic membrane coatings containing ionophores were applied. These functionalized ZnO nanorods sensors showed a high sensitivity (26.55 mV/decade) and good stability.

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Potentially useful 17-, and 22÷25-membered macrolides containing azine or hydrazide groups were synthesized from tetrahydropyran via [1+1]-condensation at room temperature of 7-oxooctyl-7-oxooctanoate, which was obtained via Tishchenko reaction from 7-oxooctanal, with hydrazine hydrate and hydrazides of several dicarboxylic acids.Polyfunctional macroheterocycles with interesting complexing properties and biological activity are widely used as interphase-transfer catalysts, extractants, analytical reagents, and materials for creating ion-selective electrodes [1-3].Herein we report the synthesis of 17-(9), 22-(10), 23- (11), 24- (12), and 25-membered (13) macrolides that may exhibit complexing properties and biological activity and contain azine or hydrazide functional groups. The synthetic scheme is based on chemo-and regioselective transformations of a ketoalcohol (2) that is accessible in three steps from tetrahydropyran (1) [4]. Corey oxidation of 2 produced ketoaldehyde 3, which has been used to synthesize 9-oxo-2E-decenoic acid (multifunctional pheromone of honeybee Apis mellifera L.) [5], and small quantities (up to 15%) of 7-oxooctyl-7-oxooctanoate (4) by disproportionation of 3 via a Tishchenko reaction. The yield of 4 could be increased (up to 70%) by using the classical method [6] with catalytic quantities of aluminium triisopropoxide.[1+1]-Condensation of 4 in dioxane at high dilution and room temperature with hydrazine hydrate or dihydrazides of malonic (5), succinic (6), glutaric (7), and adipic (8) acids and subsequent successive work up of the reaction mixture with CH 2 Cl 2 and hexane (1:10 ratio) produced in good yields (40-50%) macrolides with azine (9) or hydrazide (10-13) groups, respectively.

An area of application of tetrahydropyran has been expanded in the directed synthesis of macroheterocycles with ester and hydrazide fragments. The structures of the obtained macrocycles were proved by IR and NMR spectroscopy as well as mass spectrometry. We have already reported the synthesis of tetrahydropyran-based 9-oxo-2Е-decenoic acid(2) as the multifunctional pheromone [Chem. Nat. Compd. 2008, 44, 74-76] of queen honeybee Apis melliphera L., 7-oxooctyl-7-oxooctanoate (3) [Bashkir University Bulletin 2008, 3, 466-469 (in Russ.)] and bis (7-oxooctyl)adipate (4) [Butlerov Communications 2009, 17(5), 35-38 (in Russ.)] and also the application of key α,ω-diketones (3, 4) in the directed synthesis of a large variety of macroheterocycles with ester, azine and hydrazide functions, one of which [15,25-dimethyl-1,8-dioxo-16,17,23,24-tetraazacyclohentriaconta-15,24-dien-2,7,18,22-tetraone (10)] exhibited great antibacterial in vitro and in vivo activity [Butlerov Communications 2009, 16(4), 21-25 (in Russ.) [16,26-dimethyl-1,4,7-trioxa-17,18,24,25-tetraazacyclotetratriaconta-9,16,25,32-tetraen-8,19,23,34-tetraone (6), 8,22-dimethyl-1-oxa-9,10,20,21-tetraaza-8,21-cyclooctacosadien-2,11,19-trione (8), 8,23-dimethyl-1-oxa-9,10,20,22-teraaza-8,22-cyclononakosadien-2,11,20-trione (9), 4,25-dimethyl-28a,29,32,32a-tetrahydro-29,32-epoxy-11,18,2,3,26,27-benzadioxatetraazacyclotriaconta-3,25-dien-1,12,17,28- in its turn,3,4a,5,8, and separated from the reaction mixture. In our opinion, the introduction of pharmacophoric 7-oxabicyclo[2.2.1]heptane fragment [J. Med. Chem. 1985, 28, 1580-1590 Heterocycles 1978 Heterocycles , 9, 1749 Heterocycles -1757 ]. In this paper we put forward efficient methods to transform tetrahydropyran (1) as a disposable petrochemical product via intermediate α,ω-diketones [7-oxooctyl-7-oxooctanoate (3), bis(7-oxooctyl)adipate (4) and oxabis(ethan-1,2-diyl)(2'E,2'E)bis(9'-oxodec-2'-enoate) (5)] into potentially biologically and pharmacologically active macroheterocycles tetraone (11)] that contain the ester and hydrazide functions, including the olefin ones. The macrocycle (6) with conjugated ester groups was synthesized on the basis of unsaturated ketonic acid (2) by its transformation into the appropriate chloroanhydride, [2+1]-condensation with diethylene glycol and subsequent [1+1]-interaction between intermediate diketone diester (5) and glutaric dihydrazide. The synthesis of 28-(8) and 29-(9) member macrolides was performed by [1+1]-condensation of α,ω-dimethylketone (3) with azelaic and sebacic dihydrazides, respectively. The macrolide analog (10) exhibiting the antibacterial activity, i.e., macrocycle (11) with 7-oxabicyclo[2.2.1]heptane fragment in the form of a single di-exo-isomer, was obtained by [1+1]-condensation of the key precursor (4) with the linear dihydrazide of

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Eight potentially useful 15-, 17-, 20-, and 22-25-membered macrolides having an azine or hydrazide fragment were synthesized starting from L-menthol, tetrahydropyran, and 4-methyltetrahydropyran via [1 + 1]-condensation of hydrazine hydrate and some dicarboxylic dihydrazides with 7-oxooctyl 7-oxooctanoate, 3-methyl-7-oxooctyl 3-methyl-7-oxooctanoate, and (3R)-3,7-dimethyl-6-oxooctyl (3R)-3,7-dimethyl-6-oxooctanoate obtained by the Tishchenko reaction from 7-oxo-, 3-methyl-7-oxo, and (3R)-3,7-dimethyl-6-oxooctanals, respectively. * For preliminary communications, see [1,2].It is known [3-6] that functionalized macrocyclic compounds are widely used in organic and petrochemical synthesis, detection and separation of metals by extraction, sorption and chromatographic analytical methods, ionometry, design of cardio-and psychotropic agents and studies on mechanisms of their action, development of antimicrobial, antiparasitic, and antitumor drugs, etc.In the present article we describe efficient ways of synthesis of 15-, 17-, 20-, and 22-25-membered macrolides having an azine or hydrazide fragment starting from accessible synthetic [tetrahydropyran (I) and 4-methyltetrahydropyran (II)] and natural [L-menthol (III)] compounds. The proposed approach is based on initial transformation of cyclic substrate into the corresponding oxo aldehydes, 7-oxo-, 3-methyl-7-oxo-, and (3R)-3,7-dimethyl-6-oxooctanals IV-VI, according to the procedure reported in [1,2], and their subsequent Tishchenko disproportionation to give dioxo esters VII-IX.[1+1]-Condensation of the latter with hydrazine hydrate or malonic, succinic, glutaric, and adipic acid dihydrazides in strongly dilute dioxane solution at room temperature, followed by treatment of the reaction mixture with methylene chloride-hexane (1 : 10), afforded 40-54% of macrolides having a ketone azine (X, XI) or bis-hydrazide fragment (XII-XVII), respectively (Schemes 1, 2).The structure of macrocyclic compounds X-XVII was determined by IR spectroscopy and 1 H and 13 C NMR; according to the HPLC data, their purity was ~95%. The NMR spectra of X-XVII were analyzed by comparing with the spectra of initial compounds, dioxo esters VII-IX and dicarboxylic acid dihydrazides. The 13 C NMR spectra of compounds XI and XVII lacked signals of carbonyl carbon atoms (δ C 214.13 and 214.42 ppm) and methylene and methine groups in the α-position to the carbonyl group (δ C 35.08, 37.53 ppm), which were typical of initial dioxo ester IX. In addition, no hydrazide NH 2 signal was observed in the 1 H NMR spectrum of macrocycle XVII (δ 4.75 ppm in the spectrum of the initial hydrazide). These findings indicate that the products have cyclic structure rather than the structure of acyclic substitution products. The 13 C NMR spectrum of XI, apart from the singlet at δ C 170.64 ppm (ester carbonyl carbon atom), contained a singlet at δ C 169.24 ppm due to C=N carbon atoms, which is consistent with the formation of macrocycle possessing an azine fragment.Compound XVII displayed in the 13 C NMR spectrum a signal ...

This overview summarizes the materials on the synthesis of macrolides with nitrogen-containing fragments using macrolactonization, macroamidization and metathesis reactions at the key cyclization stage. The undying interest in macrolide synthesis is due to the fact that substances with powerful antibiotic (antimicrobial, antiviral, antiparasitic) and antitumor functions have been found among this class of organic compounds. Furthermore, there is evidence for positive effects of pharmacophoric nitrogen-containing (hydrazide, amine, amide, pyrrolidone, pyrrolizidine, oxazole, etc.) ВведениеПолифункциональные макрогетероциклы, обла-дая интересными комплексообразующими свойствами и широким спектром биологической активности, на-ходят все более широкое применение в органическом и нефтехимическом синтезе, выявлении и разделении металлов экстракцией, сорбционных и хроматографиче-ских методах анализа, ионометрии и фармакологии, что обусловлено, в первую очередь, вхождением в их состав сложноэфирной функции. Неослабевающий интерес к синтезу макролидов объясняется тем, что среди этого

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