73776-01-9Relevant academic research and scientific papers
Synthesis and spectroscopic properties of new bis-tetrazoles
Pazik, Agnieszka,Skwierawska, Anna
, p. 83 - 94 (2014/01/06)
Syntheses of N,N′-phenyltetrazole podands link with aliphatic chains containing oxygen, nitrogen and sulphur atoms, are described. The complexing properties of these compounds towards metal cations (Fe2+, Cu 2+, Zn2+, Co2+, Ni2+) were investigated by absorption and infrared spectroscopy. The UV-Vis titrations were performed to estimate the stability constant values of the respective complexes with Cu2+ ion. Changes in UV-Vis absorption spectra and IR spectra of compound 6 under various concentrations of Cu2+ ion in methanol suggest formation of very unstable complex. The structure of ligand 2 has been deduced by X-ray crystallography. The Author(s) 2012.
Application of chemometrics and quantum chemical calculations to the study of complexation equilibria between 1,8-bis(o-aminophenoxy)-3,6-dioxaoctane and some transition and heavy metal ions in acetonitrile solution
Shamsipur,Ghavami,Hemmateenejad,Sharghi,Alizadeh,Niknam
, p. 1621 - 1638 (2008/12/22)
Evolutionary factor analysis (EFA) and rank annihilation factor analysis (RAFA) were applied to resolve the two-way equilibrium spectrophotometric data for the determination of stability constants of the complexes of 1,8-bis(o-aminophenoxy)-3,6-dioxaoctan
The halogen-mediated opening of epoxides in the presence of pyridine-containing macrocycles
Sharghi, Hashem,Niknam, Khodabakhsh,Pooyan, Maryam
, p. 6057 - 6064 (2007/10/03)
The ring opening of epoxides with elemental iodine and bromine in the presence of three pyridine-containing macrocyclic diamides as new catalysts affords vicinal iodo alcohols and bromo alcohols in high yields. This new procedure occurs regioselectively under mild conditions in various aprotic solvents. The catalysts are easily recovered and can be reused several times.
Phenol-containing macrocyclic diamides as new catalysts in the highly regioselective conversion of epoxides to β-hydroxy thiocyanates
Sharghi,Nasseri,Niknam
, p. 7287 - 7293 (2007/10/03)
The regioselective ring-opening reactions of some epoxides with ammonium thiocyanate in the presence of a series of new phenol-containing macrocyclic diamides and also dibenzo-18-crown-6-, 18-crown-6-, benzo-15-crown-5-, and pyridine-containing macrocyclic diamide have been studied. The epoxides were subject to cleavage by NH4SCN in the presence of these catalysts under mild reaction conditions in various aprotic solvents. In this study, reagents and conditions have been discovered with which the individual β-hydroxy thiocyanates can be synthesized in high yield and with more than 90% regioselectivity. The results can be discussed in terms of a four-step mechanism: (1) formation of complex between catalyst and NH4SCN, (2) release of SCN- nucleophile from the complex, (3) reaction of the active nucleophile at the less sterically hindered site in the epoxide, and (4) regeneration of catalyst. The major advantages of this method are as follows: (1) high regioselectivity, (2) simple regeneration of catalyst, (3) its reuse through several cycles without a decrease in activity, and (4) ease of workup of the reaction.
The Development of a New Nitrating Agent: The Unusual Regioselective Nitration of Diphenylpolyethylene Glycols and Phenylpolyethylene Glycols with Trimethylsilyl Nitrate - BF3OEt2
Kimura, Masaru,Kajita, Kazushige,Onoda, Naoyuki,Morosawa, Shiro
, p. 4887 - 4892 (2007/10/02)
We have investigated the nitration of the following podands, 1-phenoxy-8-(2'-nitrophenoxy)-, 1-phenoxy-8-(4'-nitrophenoxy)-, and 1-(2',4'-dinitrophenoxy)-8-phenoxy-3,6-dioxaoctane (2, 3, and 4), and 1-(2',4'-dinitrophenoxy)-11-phenoxy-3,6,9-trioxaundecane (5), 1-phenoxy-3,6,9-trioxadecane (6), and 1-phenoxy-3,6,9,12-tetraoxatridecane (7), with trimethylsilyl nitrate catalyzed by BF3OEt2, which is soluble in nonpolar solvents.The reaction selectivity was measured by the ortho:para ratio of the nitrated products and was unusually large in CCl4.The structures of all isolated products, 1,8-bis(2'-nitrophenoxy)-, 1-(2'-nitrophenoxy)-8-(4'-nitrophenoxy)-, 1,8-bis(4'-nitrophenoxy)-, 1-(2',4'-dinitrophenoxy)-8-(2'-nitrophenoxy)-, and 1-(2',4'-dinitrophenoxy)-8-(4'-nitrophenoxy)-3,6-dioxaoctane (8, 9, 10, 11, and 12), 1-(2',4'-dinitrophenoxy)-11-(2'-nitrophenoxy)- and 1-(2',4'-dinitrophenoxy)-11-(4'-nitrophenoxy)-3,6,9-trioxaundecane (13 and 14), 1-(2'-nitrophenoxy)- and 1-(4'-nitrophenoxy)-3,6,9-trioxadecane (15 and 16), and 1-(2'-nitrophenoxy)- and 1-(4'-nitrophenoxy)-3,6,9,12-tetraoxatridecane (17 and 18), were confirmed by the independent preparation of these compounds using a modification of Joeger's method.We have invented a new nitrating system (trimethylsilyl nitrate and BF3OEt2) and have shown that the selectivity (o/p ratio of nitrated products) is unusually high in CCl4.
Novel Ditopic Receptors Based on the P2N2 Diphosphazane Ring: Synthesis and X-ray Structural Characterization of Cis and Trans Bis(crown ether) Annellated 1,3,2λ54λ5-Diazadiphosphetidine 2,4-Disulfide
Dutasta, Jean-Pierre,Declercq, Jean-Paul,Esteban-Calderon, Carmen,Tinant, Bernard
, p. 7136 - 7144 (2007/10/02)
The 1,3,2,4-diazadiphosphetidine ring is used for the construction of the bis(crown ether) derivative 1, which occurs as cis and trans isomers.Refluxing triethylene glycol dianilino ether 3 with hexamethylphosphorous triamide (HMPT) in toluene followed by addition of sulfur gave 1 as a crystalline material in isolated yields ranging from 25percent to 73percent.The compounds have been characterized by a combination of 1H, 13C, and 31P NMR and mass spectral data.The structural assignments of the two diastereoisomers are based on X-ray structural analysis.Crystal data at 291 K are as follows: cis-1*H2O a=11.030(9) Angstroem, b=11.169(3) Angstroem, c=18.101(13) Angstroem, α=85.68(4) deg, β=87.06(6) deg, γ=86.57(4) deg, Z=2, triclinic, space group , R=0.087 for 5888 reflections with I>/=2.5?(I); trans-1*2CH2Cl2 a=11.757(3) Angstroem, b=11.140(4) Angstroem, c=9.393(1) Angstroem, α=65.51(2) deg, β=101.12(2) deg, γ=100.63(3) deg, Z=1, triclinic, space group , R=0.054 for 3531 reflections with I>/=2.5?(I).In the cis isomer, a water molecule is encapsulated in the cavity formed by the two macrocyclic moieties facing each other.The trans isomer, which crystallizes with two dichloromethane molecules, lies on a crystallographic center of symmetry.The macrocyclic intermediate precursor 4 is characterized together with the bis(crown) derivative 5.The tervalent parent compounds are extremely sensitive to moisture.The macrocycle 8 containing a P(O)H fragment is a degradation product.
CHROMOGENIC CORONANDS. I. C-ARYLCROWN-FORMAZANS OF THE DO-, TRI-, TETRA-, PENTA-, HEXA-, HEPTA-, AND NONANEDECYNE AND DOCOSYNE SERIES
Ostrovskaya, V. M.,D'yakonova, I. A.,Poponova, R. V.,Kozlova, N. P.,Ryabokobylko, Yu. S.,Filatova, M. P.
, p. 1583 - 1588 (2007/10/02)
The 12- to 22-membered dibenzodi(oligo)oxatetraazacoronands containing a crown-ether fragment and an endocyclic C-arylformazan group (C-arylcrown-formazans) in the ring were obtained by template and nontemplate bisazocoupling of bisdiazotized bis(2-aminoa
Stereochemistry of Crown Ethers I. Conformational and Dynamic Behaviour of N-Tosyl-Substituted Diaza Crown Ethers
Kleinpeter, E.,Gaebler, M.,Schroth, W.
, p. 380 - 386 (2007/10/02)
The variable temperature 1H and 13C NMR spectra of some N-tosyl diaza crown ethers have been obtained.They are discussed with respect to the preferred conformers of the crowns and the free energies of activation of the interconversional process of the large ring.Both the preferred conformers and the ring interconversional barriers have been found strongly dependent on the structure and the ring size of the studied compounds.KEY WORDS Variable-temperature 1H and 13C NMR spectra N-tosyl diaza crown ethers Crown conformation Free energies of activation.
Macroheterocycles with an Endocyclic Azo-Group. 1. Tetraazamacrocycles Obtained from Resorcinol
Sultanov, A. V.,Savvin, S. B.
, p. 106 - 109 (2007/10/02)
High-dilution azocoupling of bisdiazotized bis-(2-aminophenyl)oligooxa (or thia)alkanes with resorcinol gives tetraazamacrocycles with two endocyclic azogroups.It is shown that azocoupling occurs exclusively at the 2- and 4-positions of the resorcinol ring.
Synthesis, N.m.r. Spectra, and Structure of Macrocyclic Compounds containing the Ferrocene Unit
Hammond, Philip J.,Bell, Alan P.,Hall, C. Dennis
, p. 707 - 715 (2007/10/02)
The condensation of 1,1'-bis(chlorocarbonyl)ferrocene with diaza-18-crown-6 gives 1,1'-(1,4,10,13-tetraoxa-7,16-diazacyclo-octadecane-7,16-diyldicarbonyl)ferrocene (5) together with its dimer 1,1'':1',1'''-bis-(1,4,10,13-tetraoxa-7,16-diazacyclo-octadecane-7,16-diyldicarbonyl)bisferrocene (6) and the separation and isolation of these compounds are described.High resolution 1H and 13C n.m.r. spectra using homo- and hetero-nuclear decoupling techniques allow a complete assignment of the spectral data for (5) and (6) and lead to a proposal of a structure for (5) involving a trans-disposition of the amide carbonyl groups.Variable-temperature n.m.r. data on (6) reveal two distinct dynamic processes within the molecule involving rotation about the ferrocene-carbonyl bond (ΔG=50 kJ mol-1, Tc=-10 deg C) and rotation about the N-CO bond (ΔG=67 kJ mol-1, Tc=+60 deg C).The preparation, 1H and 13C n.m.r. data of monocyclic compounds containing the ferrocene unit (13a-c), (14) and (15) are also described and the details of the synthesis of an 15N-labelled analogue of (13c), the macrocycle (16), are reported.
