Synthesis,properties and X‐ray structure of 5‐azido‐2‐methoxy‐1,3‐xylyl‐18‐crown‐5

5‐Azido‐2‐methoxy‐1,3‐xylyl‐18‐crown‐5 has been prepared by reacting p‐toluenesulfonyl azide with the carbanion generated from the reaction of 5‐bromo‐2‐methoxy‐1,3‐xylyl‐18‐crown‐5 with n‐butyl lithium. The asymmetric N₃ stretch of this product has been observed as a single band at 2110 cm^?1 in dichloromethane solution. Addition of solid NaSCN, KSCN and CsSCN shifts this band to 2115, 2113 and 2112 cm^?1, respectively. Computational studies of this azide at the B3LYP‐6‐31G* level in the presence and absence of Na⁺ predicted these bands to be at 2173 cm^?1 and 2184 cm^?1. For the salt‐containing solutions, additional bands were observed at 2066 cm^?1, 2056 cm^?1 and 2055 cm^?1, respectively, which are in the range expected for CN stretches. The X‐ray structure of this azide has been determined. The terminal and internal N? N bond lengths were found to be 1.127(2) and 1.245(2) Δ, respectively, which is the usual pattern for aromatic azides. The crown ether is looped over the face of the aromatic ring resulting in an angle of 38.94° between the plane defined by the aromatic ring and that defined by the five ring oxygen atoms. In addition, the CH₃ group is rotated out of the plane of the phenyl ring with C1‐C18‐O181‐C182 and C17‐C18‐O181‐C182 dihedral angles of 93.81(14)° and ‐90.54(14)°, respectively.     

Synthesis and complexing properties of double armed diaza‐15‐crown‐5 and diaza‐18‐crown‐6 ethers having 4′‐hydroxy‐3′,5′‐disubstituted benzyl groups

A series of double armed diaza‐15‐crown‐5 ethers (9a ‐ 16a) and diaza‐18‐crown‐6 ethers (9b ‐ 16b) have been prepared by the Mannich reaction of 2,6‐disubstituted phenols with the corresponding N,N'‐dimethoxymethyldiaza‐crown ethers in benzene. The crystal structures of the diaza‐18‐crown‐6 ethers having iso‐propyl (10b) , tert‐butyl (11b) , and mixed methyl and tert‐butyl groups (12b) at positions 3′ and 5′ of the phenolic side arms were determined using X‐ray diffraction methods. Competitive transport by these ligands for sodium, potassium and cesium cations were measured under basic‐source phase and acidic‐receiving phase conditions.     

Sulfenylation of heterocyclic 1,3‐dicarbonyl systems: 4‐Hydroxy‐2‐pyrones, 6‐hydroxy‐4‐pyrimidones, 4‐hydroxy‐2‐pyridones, 4‐hydroxy‐6‐pyridazinones,and 5‐hydroxy‐3‐pyrazolones

Anions of enolized heteroaromatic 1,3‐dicarbonyl systems, such as the title compounds 1, 9,14 , and 19 , react in dimethylformamide in the presence of potassium carbonate with diaryl disulfides 2 to yield arylsulfenyl derivatives ( 3, 10, 15, 20 ). The arylthiolate anions 4 formed in this reaction can be oxidized by air to yield the starting disulfides 2 again. Tetraalkylthiuram disulfides 7 react in the same manner to yield dialkylaminothiocarbonylthio derivatives ( 8, 13, 18 ) of the title compounds. Oxidation of the arylsulfenyl derivatives with hydrogen peroxide in sodium hydroxide solution usually leads to sulfoxides ( 5, 11, 16 ), whereas oxidation with peracetic acid affords sulfones ( 6, 12, 17 ).     

Synthesis,structure and in vitro cytotoxicity testing of some 1,3,4‐oxadiazoline derivatives from 2‐hydroxy‐5‐iodobenzoic acid

The syntheses of nine new 5‐iodosalicylic acid‐based 1,3,4‐oxadiazoline derivatives starting from methyl salicylate are described. These compounds are 2‐[4‐acetyl‐5‐methyl‐5‐(3‐nitrophenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6a ), 2‐[4‐acetyl‐5‐methyl‐5‐(4‐nitrophenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6b ), 2‐(4‐acetyl‐5‐methyl‐5‐phenyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl)‐4‐iodophenyl acetate, C₁₉H₁₇IN₂O₄ ( 6c ), 2‐[4‐acetyl‐5‐(4‐fluorophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate, C₁₉H₁₆FIN₂O₄ ( 6d ), 2‐[4‐acetyl‐5‐(4‐chlorophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate, C₁₉H₁₆ClIN₂O₄ ( 6e ), 2‐[4‐acetyl‐5‐(3‐bromophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6f ), 2‐[4‐acetyl‐5‐(4‐bromophenyl)‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6g ), 2‐[4‐acetyl‐5‐methyl‐5‐(4‐methylphenyl)‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6h ) and 2‐[5‐(4‐acetamidophenyl)‐4‐acetyl‐5‐methyl‐4,5‐dihydro‐1,3,4‐oxadiazol‐2‐yl]‐4‐iodophenyl acetate ( 6i ). The compounds were characterized by mass, ¹H NMR and ¹³C NMR spectroscopies. Single‐crystal X‐ray diffraction studies were also carried out for 6c , 6d and 6e . Compounds 6c and 6d are isomorphous, with the 1,3,4‐oxadiazoline ring having an envelope conformation, where the disubstituted C atom is the flap. The packing is determined by C—H…O, C—H…π and I…π interactions. For 6e , the 1,3,4‐oxadiazoline ring is almost planar. In the packing, Cl…π interactions are observed, while the I atom is not involved in short interactions. Compounds 6d , 6e , 6f and 6h show good inhibiting abilities on the human cancer cell lines KB and Hep‐G2, with IC₅₀ values of 0.9–4.5 µM.     

Propane‐1,3‐diaminium tetrachloridozincate(II) 18‐crown‐6 clathrate

The reaction of propane‐1,3‐diamine hydrochloride, 18‐crown‐6 and zinc(II) chloride in methanol solution yields the title complex salt [systematic name: propane‐1,3‐diaminium tetrachloridozincate(II)–1,4,7,10,13,16‐hexaoxacyclooctadecane (1/1)], (C₃H₁₂N₂)[ZnCl₄]·C₁₂H₂₄O₆, with an unusual supramolecular structure. The diprotonated propane‐1,3‐diaminium cation forms an unexpected 1:1 supramolecular rotator–stator complex with the crown ether, viz. [C₃H₁₂N₂(18‐crown‐6)]²⁺, in which one of the –NH₃⁺ substituents nests in the crown and interacts through N—H...O hydrogen bonding. The other –NH₃⁺ group interacts with the [ZnCl₄]²⁻ anion via N—H...Cl hydrogen bonding, forming cation–crown–anion ribbons parallel to [010].     

A Spectrophotometric Investigation of the Interaction of Iodine with Dibenzyldiaza‐18‐crown‐6, Aza‐15‐crown‐5 and N‐phenylaza‐15‐crown‐5 in Chloroform Solution

The complex formation reactions between iodine and DBzDA18C6, A15C5 and N‐phenylA15C5 have been studied spectrophotometrically in chloroform solution. In the case of DBzDA18C6 is the resulting 1:2 (ligand…I⁺)I₃^?, while, in the case of A15C5 and N‐phenylA15C5 a 2:2 molecular complex of [(ligand)₂…I⁺]I₃^? type was formed. The spectrophotometric results indicate that gradual release of triiodide ion from its contact ion paired form in the molecular complex into the solution is the rate‐determining step of the reaction. The kinetic rate constants for the complexation reactions were determined at different temperatures, and activation parameters were calculated from Arrhenius and Eyring equations.     

4‐Carboxypyridinium perchlorate 18‐crown‐6 dihydrate clathrate and 4‐carboxypyridinium tetrafluoroborate 18‐crown‐6 dihydrate clathrate

Mixtures of 4‐carboxypyridinium perchlorate or 4‐carboxypyridinium tetrafluoroborate and 18‐crown‐6 (1,4,7,10,13,16‐hexaoxacyclooctadecane) in ethanol and water solution yielded the title supramolecular salts, C₆H₆NO₂⁺·ClO₄⁻·C₁₂H₂₄O₆·2H₂O and C₆H₆NO₂⁺·BF₄⁻·C₁₂H₂₄O₆·2H₂O. Based on their similar crystal symmetries, unit cells and supramolecular assemblies, the salts are essentially isostructural. The asymmetric unit in each structure includes one protonated isonicotinic acid cation and one crown ether molecule, which together give a [(C₆H₆NO₂)(18‐crown‐6)]⁺ supramolecular cation. N—H...O hydrogen bonds between the protonated N atoms and a single O atom of each crown ether result in the 4‐carboxypyridinium cations `perching' on the 18‐crown‐6 molecules. Further hydrogen‐bonding interactions involving the supramolecular cation and both water molecules form a one‐dimensional zigzag chain that propagates along the crystallographic c direction. O—H...O or O—H...F hydrogen bonds between one of the water molecules and the anions fix the anion positions as pendant upon this chain, without further increasing the dimensionality of the supramolecular network.     

Synthesis and Optical Properties of 2,13‐Dibenzothiazol‐2′‐yldibenzo[b,k]‐18‐crown‐6

A new crown ether of 2,13‐dibenzothiazol‐2′‐yldibenzo[b,k]‐18‐crown‐6 was synthesized from 2,13‐diformyl‐ dibenzo[b,k]‐18‐crown‐6 with 2‐aminothiophenol. The binding behavior and the optical properties of the crown ether were examined through UV‐visible spectroscopy and fluorescence spectroscopy. When complexed with Na⁺, K⁺, Rb⁺ and Cs⁺ ions, it led to intramolecular charge transfer and caused the changes of the fluorescence spectra. The protonation of the crown ether was also studied.     

Synthesis and conformational analysis of a small meta‐cyclophane,bis(5‐carbomethoxy‐1,3‐phenylene)‐14‐crown‐4

A small cyclophane, bis(5‐carbometh‐oxy‐1,3‐phenylene)‐14‐crown‐4 (BCMP14C4, 3 ) and its diacid, bis(5‐carboxy‐1,3‐phenylene)‐14‐crown‐4 ( 4 ), were synthesized and characterized. The solid‐state molecular structures of 3 and 4 were determined by X‐ray crystallography as ladder or stepped conformations in which the two aromatic rings are antiparallel to each other without overlap and the ethylene tethers both take trans‐conformations. Diester 3 is formed in the lowest cyclization yield (under the same reaction conditions) and exhibits the highest melting point compared to its larger ring (20‐, 26‐ and 32‐membered) analogs. In CD₂Cl₂ solution, diester 3 exists predominantly as a nonplanar gauche–gauche structure as deduced by H NMR studies. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:48–54, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20393     

Synthesis of 3‐(2‐hydroxy‐1‐phenylethyl)‐ and 3‐(2‐hydroxy‐2‐phenylethyl)adenine,DNA adducts derived from styrene

3‐(2‐Hydroxy‐2‐phenylethyl)‐ and 3‐(2‐hydroxy‐1‐phenylethyl)adenine, DNA adducts derived from styrene, along with their 9‐substituted analogues were prepared by alkylation of 8‐bromoadenine with corresponding allyl‐protected bromohydrins followed by a new deallylation procedure using tetrakis(triphenylphosphine)palladium catalyzed reductive cleavage by poly(methylhydrosiloxane) in the presence of p‐toluenesulphonic acid. This novel procedure proved to be useful for purine derivatives, which were resistant to other deallylation protocols. Structure of positional isomers was assigned using 2D NMR experiments HMBC and HMQC.     

Synthesis and optical properties of cis‐dibenzothiazolyldibenzo‐24‐crown‐8

New crown ether carrying two fluorionophores of cis‐dibenzothiazolyldibenzo‐24‐crown‐8 was synthesized from cis‐diformyldibenzo‐24‐crown‐8 and 2‐aminobenzenethiol. The binding behavior and the optical properties of the crown ether were examined through UV‐visible spectroscopy and fluorescence spectroscopy. When complexed with Na⁺, K⁺, Rb⁺, and Cs⁺ ions, it led to intramolecular charge transfer and caused the changes of the fluorescence spectra. The protonation of the crown ether was also studied. With protonation using CF₃COOH, the absorption bands and the fluorescence spectroscopy changed, the maximal fluorescence wavelengths red shifted and the fluorescence intensity with the maximum at 433 nm enhanced strongly. J. Heterocyclic Chem., (2011).     

Pb(18‐crown‐6)Cl2 and Hg(18‐crown‐6)I2: Molecular Dihalides Trapped in a Crown Ether

Pb(18‐crown‐6)Cl₂ and Hg(18‐crown‐6)I₂ are obtained as transparent colourless crystals of needle and hexagonal shape, respectively, by isothermal evaporation of their dichloromethane solutions. Pb(18‐crown‐6)Cl₂ crystallizes with the trigonal crystal system [ , no. 148, a = b = 1176.3(2), c = 1191.8(3) pm, V = 1428.2(5) 10⁶·pm³, Z = 3] whereas Hg(18‐crown‐6)I₂ crystallizes with the orthorhombic crystal system (Pnma, no. 62, a = 1613.9(2) pm, b = 2822.2(5) pm, c = 841.3(1) pm, V = 3832(1)10⁶·pm³, Z = 8). Both compounds are characterized by linear MX₂ (HgI₂ or PbCl₂) molecular units which are encrypted by the crown ether. In both cases, the divalent metal ion resides in the middle of the crown ether resulting in a hexagonal bipyramidal coordination environment for the metal cations. The molecular symmetry comes close to D_3d. Hg(18‐crown‐6)I₂ and Pb(18‐crown‐6)Cl₂ differ in the way the single MX₂@18‐crown‐6 units are packed. Whereas the Hg(18‐crown‐6)I₂ molecules are arranged in a (distorted) cubic closest packing, the Pb(18‐crown‐6)Cl₂ molecules adopt a hexagonal closest packing.     

Synthesis of cyanine dyes derived from benzotellurazo‐15‐crown‐5

A series of crown ether cyanine dyes including crown ether styryl cyanine dyes, crown ether merocyanine dyes and crown ether squarylium cyanine dyes (unsymmetric and symmetric) derived from key intermediate 2‐methyl‐5,6(15‐crown‐5)benzotellurazole ( 1 ) were prepared.     

Crystallographic report: Thallium(18‐crown‐6) hexafluorophosphate, [Tl(18‐crown‐6)](PF6)

Thallium(18‐crown‐6) hexafluorophosphate was prepared and its structure was determined by X‐ray diffraction analysis. The Tl⁺ ion is surrounded by six oxygen atoms of 18‐crown‐6 and three fluorine atoms of , forming a sandwiched structure. If the three Tl–F interactions were considered significant, the coordination number in the title compound would be nine. Copyright © 2003 John Wiley & Sons, Ltd.     

The sodium salt of 2‐hydroxy‐5‐nitrobenzylsulfonic acid

The structural data for sodium 2‐hydroxy‐5‐nitro­benzyl­sulfonate monohydrate, Na⁺·C₇H₆NO₆S^?·H₂O, which mimics an artificial substrate for human aryl­sulfatase A, viz. p‐­nitrocatechol sulfate, reveal that the geometric parameters of the substrate and its analogue are very similar. Two water mol­ecules, the phenolic O atom and three sulfonate O atoms form the coordination sphere of the Na⁺ ion, which is a distorted octahedron. The Na⁺ cations and the O atoms join to form a chain polymer.     

1,10‐Diaza‐18‐crown‐ether,Modified by Phosphonate Pendant Arms – Synthesis,Structure, and Picrate Extraction Properties

Reaction of O,O′‐diisopropyl‐3‐methyl‐1,2‐butadienylphosphonate with 1,10‐diaza‐18‐crown‐6 in the presence of a catalytic amount of iPrONa leads to the new crown‐ether derivative, containing phosphonate pendant arms ( L ). The structure of the compound obtained was investigated by single crystal X‐ray diffraction analysis, IR, ¹H and ³¹P{¹H} NMR spectroscopy, and microanalysis. In the crystal structure the side arms of L are in an anti disposition relative to the macrocyclic cavity. It was established that phosphorylation of 1,10‐diaza‐18‐crown‐6 by allenylphosphonate results in an increase of extraction of NaPic and KPic, whereas LiPic and NH₄Pic are extracted practically in the same level.     

Aqueous solution and solid state interactions of lanthanide ions with a methacrylic ester polymer bearing pendant 15‐crown‐5 moieties

The interaction between trivalent lanthanide ions and poly(1,4,7,10,13‐pentaoxacyclopentadecan‐2‐yl‐methyl methacrylate), PCR5, in aqueous solution and in the solid state have been studied. In aqueous solution, evidence of a weak interaction between the lanthanides and PCR5 comes from the small red shift of the Ce(III) emission spectra and the slight broadening of the Gd(III) EPR spectra. From the Tb(III) lifetimes in the presence of H₂O and D₂O the loss of one or two water coordinated molecules is confirmed when Tb(III) is bound to PCR5. An association constant of the order of 200 M^?1 was obtained for a 1:1 (lanthanide:15‐crown‐5) complex from the shift of the polymer NMR signals induced by Tb(III). A similar association constant is obtained from the differences of the molar conductivity of Ce(III) solution at various concentrations in presence and absence of PCR5. When Tb(III) is adsorbed on PCR5 membranes, lifetime experiments in H₂O and D₂O confirm the loss of 5 or 6 water coordinated molecules indicating that in solid state the lanthanide(III)‐PCR5 interaction is stronger than in solution. The adsorption of Ce(III) in PCR5 membranes shows a Langmuir type isotherm, from which an equilibrium constant of 39 M^?1 has been calculated. SEM shows that the membrane morphology is not much affected by lanthanide adsorption. Support for lanthanide ion–crown interactions comes from ab initio calculations on 15‐crown‐5/La(III) complex. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1788–1799, 2007     

Synthesis,structure and electrocatalytic properties of a water‐soluble copper complex supported by 2‐ethyl‐2‐(2‐hydroxybenzylideneamino)propane‐1,3‐diol ligand

The reaction of 2‐ethyl‐2‐(2‐hydroxybenzylideneamino)propane‐1,3‐diol (H₃L) with CuCl₂⋅2H₂O affords a new copper complex, [ClCu(H₂L)], which has been determined using X‐ray crystallography. In the solid, copper atom is four‐coordinated by two oxygen atoms and one nitrogen atom from the ligand and one chlorine atom. Electrochemical studies show that the complex can act as an electrocatalyst for hydrogen evolution from a dimethylformamide solution of acetic acid and a neutral buffer (pH = 7.0) with a turnover frequency of 46.2 and 482 moles of hydrogen per mole of catalyst per hour at an overpotential of 941.6 and 837.6 mV, respectively.     

1‐hydroxy‐1,1‐bis(H‐phosphinates): Synthesis,stability, and sorption properties

A synthesis of 1‐hydroxy‐1,1‐bis(H‐phosphinates) from acylchlorides is described. Solid‐state structures of two bis(phosphinates) determined by X‐ray diffraction showed variations in the P C distances. The compounds show negligible sorption on hydroxyapatite and an intermediate chemical stability in aqueous solution. The hydrolysis occurs in acidic as well as alkaline media. Hydrolysis rates of four derivatives show the lowest stability for aromatic derivatives as a result of the electron‐withdrawing effect. Main products of hydrolysis are 1‐hydroxy‐(H‐phosphinates) and phosphorous acid. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:195–201, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.21003