Synthesis and Characterization of a New (E, E)-Dioxime and Its Homo and Heteronuclear Complexes Containing Macrobicylic Moieties

A new N,N'-substituted diaminoglyoxime (H ₂ L) containing a diazatetraoxamacrobicycle [2.2.2_B] has been synthesized from an aromatic primary amine attached to the cryptand moiety and cyanogen-di-N-oxide. The BF₂ ⁺-capped Co(III) and heterotri-nuclear complexes of thevic-dioxime were prepared. The new compounds werecharacterized by a combination of elemental analysis and ¹H NMR,¹³C NMR, IR and MS spectral data.     

Coumarin-based symmetrical bisamide as fluorescent and colorimetric probes for copper ions

Coumarin-based new symmetrical bisamide 1 has been designed and synthesised. The bisamide 1 fluorometrically recognises Cu²⁺ in CH₃CN containing 0.06% DMSO by exhibiting an increase in emission upon complexation. In comparison, the isomeric structure 2 also reports the selectivity for Cu²⁺ under identical condition by showing an opposite mode of emission. In addition, Cu²⁺ gives rise to a change in colour of the solution of 1, which is clearly visible to the naked eye.     

Two new polyacetylene glycosides from the roots of Codonopsis tangshen Oliv.

Two new polyacetylene glycosides, tangshenyne A (1) and tangshenyne B (2), along with six known polyacetylenes were isolated from an 85% MeOH extract of the roots of Codonopsis tangshen Oliv. The chemical structures of the new compounds were determined on the basis of extensive spectroscopic analyses, including UV, IR, 1D and 2D NMR (¹H–¹H COSY, HSQC and HMBC) and HR-ESI-MS.     

Facile one-pot synthesis of new [1,2,4]triazolo[1,5-a]pyridine derivatives by ultrasonic irradiation

Herein, we report an ultrasonic promoted facile and convenient “one-pot” procedure for the synthesis of new [1,2,4]triazolo[1,5-a]pyridine derivatives 3, 4 and 5, using Amberlite IRA-400, in short reaction times and high yields and its comparison with classical reaction conditions. The structures of new compounds were assigned with the help of analytical ¹H, ¹³C NMR, and mass spectral studies.     

A dansyl-based optical probe for detection of singly and doubly charged anions

This paper reports the synthesis of a new molecule, 5-(dimethylamino)naphthalene-1-sulfonic acid 2,3-bis(3-phenylureido)phenyl ester (1), as an optical probe for anions. The effect of the presence of various anions on the spectroscopic properties of 1 was examined using UV–vis absorption spectroscopy, fluorescence and ¹H NMR titration experiments. Strong binding of 1 to carboxylate, oxalate, cyanide and dihydrogen phosphate anions resulted in an increase in the emission of 1 and changes in its ¹H NMR chemical shifts. Binding constants of 1 to anions were also calculated based on the binding isotherms derived from the spectroscopic titrations.     

Stability constants of complexes formed by new Schiff-base lariat ethers derived from 4,13-diaza-18-crown-6 with Ag+, Pb2+, Cu2+ cations determined by competitive potentiometry

The stability of complexes formed by a series of Schiff-base lariat ethers, derived from 4,13-diaza-18-crown-6, 1 with Ag⁺, Pb²⁺, Cu²⁺ cations, has been comparatively determined, in methanol: dichloromethane solution. We present here the synthesis and an interesting competitive potentiometry method useful for the stability constant determination for a new family of Schiff-base bibracchial lariat ethers. The stability constants and the selectivity in competitive complexation of Ag⁺, Pb²⁺ and Cu²⁺ cations by macrocyclic receptors 1–7 (L), can be accurately evaluated and species distribution diagrams can be calculated for individual system. In all cases further functionalization of bibracchial lariat ethers 2–7 is accompanied by an increasing of the selectivity, relative to the complexes of the initial 4,13-diaza-18-crown-6 macrocycle 1.     

Polymer Supported Calix[4]arene Schiff Bases: A Novel Chelating Resin for Hg2+ and Dichromate Anions

This article describes the synthesis and characterization of two new calix[4]arene Schiff bases and their polymeric resins. The extraction properties of these “proton switchable extractants” with alkali, transition, post transition metal cations and for dichromate anions are reported. The two new calix[4]arene based Schiff bases (5 and 6) have been synthesized from 5,17‐diformyl‐25,27‐dipropoxy‐26,28‐dihydroxycalix[4]arene (4) by treatment with 3‐amino‐methylpyridine and 1,8‐diaminooctane in two separate reaction flasks following the same procedure. Compounds 5 and 6 have been appended to a polymeric resin by treatment with Merrifield resin through a nucleophilic substitution reaction. The receptor compounds (3 and 5–8) do not extract alkali metal cations, but show some selectivity toward transition metal cations, and a particularly high selectivity to Hg²⁺ and Pb²⁺. The protonated forms of all of the calixarene‐based receptors are good extractants for transferring Cr₂O₇ ^2?/HCr₂O₇ ^? anions from an aqueous into a dichloromethane layer.     

The synthesis and characterization of new phthalocyanines containing hexaazadithia macrobicyclic moieties

The new metal-free and metallo phthalocyanines (4) and (5) bearing four tetrasubstituted hexaazadithia macrobicycles on peripheral positions, have been synthesized. Phthalonitrile (3) has been synthesized from the reaction of (1,3,6,9,11,14 hexaazatricyclo [12.2.1.1^6,9]) (1) and 1,2-bis(2-iodomercaptoethyl)-4,5-dicyanobenzene (2). The new compounds were characterized by elemental analysis, and IR, ¹H, ¹³C-NMR, UV-Visible and mass spectral data.     

Hydrothermal synthesis,crystal structure and fluorescence of a 3D organic–inorganic hybrid coordination network [CuI(4,4′-bipy)]4[ δ -Mo8O26] exhibiting an interesting polymorphism

A new three-dimensional (3D) extended solid [Cu^I(4,4′-bipy)]₄[δ-Mo₈O₂₆] (1) built on {Cu(4,4′-bipy)}⁺ (bipy?=?bipyridine) and isopolymolybdate anion [δ-Mo₈O₂₆]^4? has been synthesized and characterized by elemental analysis, IR, TG, X-ray powder diffraction and single-crystal X-ray diffraction analysis. Compound 1 shows six coppers bonded to [δ-Mo₈O₂₆]^4? to form inorganic planes which are linked by 4,4′-bipy into a 3D network, the first example of [δ-Mo₈O₂₆]^4? six-connected linkage based on an organic-inorganic coordination polymer. A polymorphism of compound 1 was found which has an identical molecular formula but absolutely different structure. The influence of the synthesis conditions of 1 has been studied. Furthermore, the fluorescence of 1 is reported.     

1,4-Diacyl-3-acylamino-5-aryl-4,5-dihydro-1H-1,2,4-triazoles: Ring closure products of aromatic carbaldehyde (diaminomethylene) hydrazones with acylating agents

Summary Treatment of aromatic carbaldehyde (diaminomethylene)hydrazones1 with hot acetic anhydride or benzoyl chloride affords 1,4-diacyl-3-acylamino-5-aryl-4,5-dihydro-1H-1,2,4-triazoles2. In contrast, a new type of 0,N-acetal with an 1,2,4-triazole substructure (3) is obtained from 4-pyridine-carbaldehyde (diaminomethylene)hydrazone (li) by using a similar reaction procedure. The structures of all novel compounds were confirmed by spectroscopic data (¹H and¹³C NMR, MS, IR); some representative compounds were also studied by X-ray analysis.Dedicated to Professor Dr.S. Makleit on the occasion of his 65^th birthday.     

Ring–Opening of a Carbohydrate Triflate to form an Acyclic Alkene

ABSTRACT

The ease with which carbohydrate trifluoromethanesulfonates (triflates) undergo substitution reactions with a wide variety of nucleophiles¹ has allowed these compounds to play an increasingly important role in synthetic carbohydrate chemistry.² The exceptional reactivity of triflates also creates an opportunity for unusual reactions to occur;³ for example, triflyl group migration⁴ and internal displacement by very weak nucleophiles⁵ both have been observed. Also, carbohydrate triflates have been used as alkylating agents in oligosaccharide synthesis.⁶ In this communication a new triflate reaction is described. This new process is one in which departure of the triflyloxy group is accompanied by ring opening to give an acyclic alkene.     

Intramolecular Diastereoselective Cascade Cyclization Reaction of N,N′-Bis(Salicylidene)Cyclohexanediimine with Phosphoryltrichloride to a Bis(Chlorophosphorylated) Decahydro-2,4-DI (2-Hydroxyphenyl)Benzo[d][1,3,6]oxadiazepine

Abstract

A new type of cascade cyclization was observed in the phosphorylation reaction of (R,R)- or (S,S)-N,N′-bis(salicylidene)cyclohexanediimine with phosphoryltrichloride, which resulted in the formation of bis(chlorophosphorylated) decahydro-2,4-di(2-hydroxyphenyl)benzo[d][1,3,6]oxadiazepine with two new stereogenic phosphorus atoms and two new stereogenic carbon atoms in the oxadiazepine ring in the β-position to phosphorus. During the synthesis, the N atom attacks the phosphorodichloridate group with the formation of the P–N bond to give an asymmetric phosphorus atom and an iminium ion. This compound with six stereogenic centers crystallizes in the monoclinic centrosymmetric space group P2₁/c and the crystal structure together with solution and solid-state MAS ¹³C and ³¹P NMR studies reveals a preferential formation of stereoisomers.     

NEW EVIDENCE FOR ISOMERISM OF THE FORMAZYL GROUP. SYNTHESIS OF SELECTIVELY PROTECTED 2-DEOXY-GALACTOSE FORMAZANS

A new application of the formazyl activation provided selectively protected new derivatives of both 2-deoxy-D-galactose and 2-acetamido-2-deoxy-D-galactose formazans from 6-amino-6-deoxy-D-galactose 6,4-cyclic carbamate (1) under very simple conditions. The ¹H NMR spectrum of the acetylated 2-deoxy derivative 7 revealed an equilibrium between chelated and unusual non-chelated forms of the formazan moiety in solution.     

New Look into the Synthesis of Polyhalogenoarylphosphanes

The present study shows new aspects of the synthesis of polyhalogenoarylphosphanes. The sterically hindered anions Ph(R)P-Y^? (1a–c, Y = O, lone pair; R = Ph, Bu^t) have been used to show the complexity of the reaction between phosphorus nucleophiles and hexahalogenobenzenes or 9-bromofluorene (E3). The Ph(Bu^t)P-O^? (1a) anion reacts with hexachlorobenzene (E1), hexafluorobenzene (E2), or E3 to give Ph(R)P(O)X (4a–c, X = F, Cl, Br) with the release of the corresponding carbanion as a nucleofuge, followed by side reactions. In contrast, the lithium phosphides Ph(R)PLi (1b,c) react with hexahalogenobenzenes to give the corresponding diphosphanes 5a,b as the main product and traces of P-arylated products, i.e., Ph(R)P-C₆X₅ (10a,b, X = Cl, F). Unexpectedly, Ph(Bu^t)PLi (1b) reacts with an excess of 9-bromofluorene to give only halogenophosphane Ph(Bu^t)P-X.     

A Convenient Synthesis of N-Functionalized Perfluoroalkanesulfonamides

This article describes the synthesis of new N-functionalized perfluoroalkanesulfonamides (5) with two sulfonamides functionalities. Perfluoroalkanesulfonyl fluoride underwent a reaction with 2-chloroethylamine hydrochloride or 3-bromopropylamine hydrobromide to give N-(2-chloroethyl or 3-bromopropyl) perfluoroalkanesulfonamides (1). Reaction of (1) with potassium thiocyanate gave N-(2-thiocyanatoethyl or 3-thiocyanatopropyl) perfluoroalkanesulfonamides (3). The sulfonyl chloride derivatives (4) were prepared by reaction of 3 with sulfuryl chloride. In the last step, 4 reacted with ammonia to give the bis sulfonamides derivatives (5). The structures of all new compounds prepared were determined by ¹H, ¹⁹F, and ¹³C NMR spectroscopies and by HR-MS.     

Selective ion clefts based on a three-bridged [43]cyclophane

A variety of new three-bridged cyclophanes, clefts4–14, have been conveniently prepared, and their cation-binding properties have been examined. Compounds4–6 have a special affinity for alkali metal cations. Ethyl ester5 and methyl ester4 selectively formed 2:1 complexes with K⁺ and Na⁺ ions, respectively. Clefts11–13, which possess pyridyl groups, bind Ag⁺ cation exclusively.¹H NMR titration studies confirmed that11 or12, having 2- or 3-pyridyl groups, form a 1:1 complex with Ag⁺ cation, while13, with 4-pyridyl ligating groups, forms a 2:1 complex. Cleft10, with aminimide groups, also shows an affinity for Ag⁺ cation in a 2:1 ratio in a polar solvent, while it forms a 1:1 complex in a nonpolar solvent. The same solvent effect was observed for clefts13 and15c, which is discussed qualitatively.     

Synthesis and Extraction Studies of a Versatile Calix[4]arene-Based “Proton-Switchable Extractant” for Toxic Metals and Dichromate Anions

The article describes the syntheses and extraction properties of a new calixarenebased extractant 5, which has been synthesized from5,11,17,23-tetra-tert-butyl-25,27-bis(chlorocarbonyl-methoxy)-26,28-dihydroxycalix[4]arene(4) by treatment with isoniazid (isonicotinic acid hydrazide) in the presence ofpyridine. The compound 5 was converted to its methyl iodide salt (6) by refluxing 5 with methyl iodide in acetonitrile. In this synthesis it was thought to explore the role of pyridinium sites in the extraction of HCr₂O ₇ ^- /Cr₂O ₇ ^2- anions. The complexing properties of 5 toward selected alkali/transition metal cationsand HCr₂O ₇ ^- /Cr₂O ₇ ² - anions are reported. It has been observed that receptor 5 does not extract alkali metal cations but shows an excellent selectivity toward transition metals. The protonated pyridinium form of 5 is an effective formfor transferring the HCr₂O ₇ ^- /Cr₂O ₇ ^2- anions from an aqueous into adichloromethane layer.     

Construction of Extended and Polymeric 1,3-Dithiolane and Tetrathiafulvalene Derivatives using Cycloaddition of Bun 3P.CS2

Abstract

Cycloaddition of the adduct between Buⁿ ₃P and CS₂ to strained double bonds such as in norbornene gives novel zwitterionic products such as 5. This dissociates to the ylide 4 so that carrying out the reaction in the presence of an aldehyde leads to a Wittig reaction to give 2-alkylidene-1,3-dithiolanes. The compound 5 reacts with acetylenic dipolarophiles by cycloaddition accompanied by loss of Buⁿ ₃P to give dihydro-TTF derivatives. Both these reaction types also occur for norbornadiene and by using this together with dialdehydes or diacetylenes a range of new sulfur-rich extended and polymeric structures have been obtained.     

New chelating agents for colorimetric determination of calcium

Two new calcium chromoionophores2 and3 are described and their potential application to colorimetric determination of calcium is assessed. Chromogenic compound2 bears two acetic acid chelating groups and a 4-(4-nitrophenyl)azophenol chromophore. Its complexation of Ca²⁺ at pH 9.0 is accompanied by a 109-nm bathochromic shift and increase in the absorptivity. Triaryl chromoionophore3 bears two phosphonic acid chelating groups and the same azophenol chromophore. Compound3 exhibits a 107-nm bathochromic shift of the absorption maximum, an increase in the absorptivity upon complexation with Ca²⁺, and good selectivity for Ca²⁺ over Mg²⁺ at pH 7.0. Both chromoionophores exhibit linear responses from 0 to 4×10^–3 M Ca²⁺.     

Synthesis and Characterization of a Novel Phosph(V)azane-Tin(IV) Complex

Abstract

The reaction of bis(anilino)phosphine oxide (C₆H₅NH)₂P(O)H, 1 with Bu₂ ⁿSnCl₂ in the presence of an excess of triethylamine (TEA) in dry tetrahydrofurane (THF) yields the novel N,O-bonded tin complex Bu₂ ⁿSn[NPh(O)P(H)NPh(HNEt₃)]₂, 2. TEA is used as a base to deprotonate the phosphazane ligand and is separated as Et₃NH⁺Cl^?, whereas HTEA⁺ exists in the final product 2 and act as a charge balancing and H-bond structure–directing agent. This new compound has been fully characterized by means of IR, MS, and multinuclear (¹H, ³¹P, and ¹¹⁹Sn NMR) spectroscopy.