44995-78-0Relevant academic research and scientific papers
Design, synthesis and membrane ion transport properties of cystine- and serine-based cyclo-4-oxa-heptane-1,7-bisamides
Ranganathan, Darshan,Samant, Manoj P,Nagaraj,Bikshapathy
, p. 5145 - 5147 (2002)
A new class of cyclobisamides, having the general profile of amino acid (cystine or serine)-ether composites, as potentially efficient ion transporters has been designed and synthesized. In model membranes, the adamantane harboring composites exhibited 57-66% of gramicidin A activity in ion transport.
Synthesis and Am/Eu extraction of novel TODGA derivatives
Iqbal, Mudassir,Huskens, Jurriaan,Verboom, Willem,Sypula, Michal,Modolo, Giuseppe
, p. 827 - 837 (2011/12/02)
Various ligands with structural modifications of the N,N,N',N'-tetraoctyl- 3-oxapentanediamide (TODGA) skeleton were synthesised in good yields. These modifications include (1) the increase in chain length from one carbon to two carbons between the central ether oxygen atom and the amide moieties, (2) the addition of substituents on the carbon between the central oxygen atom and the amide moieties on one and both sides of the central oxygen, (3) the replacement of the central oxygen by a (substituted) nitrogen atom and (4) synthesis of a rigidified glycolamide. The effect of the structural modifications on their extraction behaviours toward Am(III) and Eu(III) at various nitric acid concentrations was studied. In most of the cases, the extraction does not exceed that of TODGA in the entire acidity range of 0.001-4mol/l HNO3. The extraction behaviour of monomethyl-TODGA derivative 10a resembles that of TODGA at high nitric acid concentrations. However, at lower acidities, its D values are much lower, which is beneficial for possible back-extraction steps. The aza-tripodal ligands 18a,b show reverse extraction properties compared to TODGA as far as the pH influence is concerned: at pH 2, the DAm values are 49.9 and 3.1, the DEu values are 5.9 and 0.2, and the S Am/Eu values are 8 and 11, respectively.
The Small Cage 12,17-Dimethyl-5-oxa-1,9,12,17,-tetra-azabicyclononadecane (L): its Synthesis, Characterization, and 'Proton Sponge' Behaviour. The Crystal Structure of the Dipicrate Salt (Picrate)2
Bianchi, Antonio,Ciampolini, Mario,Micheloni, Mauro,Nardi, Nicoletta,Valtancoli, Barbara,et. al.
, p. 1131 - 1138 (2007/10/02)
The synthesis and characterization of the new oxa-azamacrobicycloalkane 12,17-dimethyl-5-oxa-1,9,12,17-tetra-azabicyclononadecane (L) are described.Its basicity behaviour in both aqueous and water-Me2SO (50:50 mol/mol) solutions has been investigated by potentiometric and spectroscopic (1H and 13 C n.m.r.) techniques.In aqueous solution it behaves as a very strong base (proton sponge) in the first protonation step, and as a relatively strong base in the second step (log k2 = 11.21).In the mixed water-Me2SO solvent both protonation constants have been measured: log k1 = 14.0 and log k2 = 8.2. 1H N.m.r. experiments indicate that in the monoprotonated species H(L)+ the proton is rapidly exchanged with acidic hydrogens on the n.m.r. timescale. 1H-1H and 1H-13C two-dimensional n.m.r. experiments allowed the unequivocal assignment for all the 1H proton and 13C resonances of both species H(L)+ and H2(L)2+.Crystals of (picrate)2 are monoclinic, space group P21/n, a = 12.868(8), b = 17.201(2), c = 16.614(2) Angstroem, β = 110.18(1) deg, and Z = 4; final R values of 0.090 (Rw = 0.090) for 3801 observed reflections.The four basal nitrogen atoms and the apical oxygen atom are located at the apices of a slightly distorted square pyramid.X-Ray analysis shows that the protonation occurs on the NCH3 groups.Each hydrogen atom of the NH+CH3 interacts with the oxygen atom, the O...H distances 2.328(16) and 2.112(18) Angstroem, and with both bridgehead nitrogen atoms, the H...N distances ranging from 2.32 to 2.34 Angstroem.This arrangement makes the overall structure very stable from the thermodynamic point of wiew and explains the unusually high basicity of (L) in both first- and second-protonation step.
MACROCYCLIC AND MACROPOLYCYCLIC COMPOUNDS BASED UPON 1,3-DISUBSTITUTED PROPANE UNITS
Pratt, John A. E.,Sutherland, Ian O.,Newton, Roger F.
, p. 13 - 22 (2007/10/02)
Synthetic routes to the macrocyclic polyamine derivatives (1) and (3) are described, together with an investigation of the complexing properties of the triamines (1d) and (3d) with primary alkylammonium cations.Macrotricyclic and macrotetracyclic compounds may be obtained from the macrocycle (1) by a stepwise procedure whereas macrocycle (3b) can be converted into a macrotricyclic derivative in a one step alkylation procedure.The alkylation of the tetrahydropyrimidone (18) with α,α'-dibromo-m-xylene gives the calix arene analogue (19) which adopts the 'cone' (21a) and '1,3-alternate' (21b) conformations.The macrocyclic hexa-amine (23) may be synthesized by a simple alkylation procedure whereas the octa-amine (27) required a systematic stepwise synthesis.The hexa-amine salt (23)*6 HBr shows selectivity in forming inclusion complexes with the dicarboxylate anions (1-)O2C(CH2)nCO2(1-).
SYNTHESIS OF 32-CROWN-8 TETRAESTER COMPOUND: MODEL OF MACROTETROLID ANTIBIOTICS
Samat, Andre,Bibout, Mohammed El Malouli
, p. 469 - 472 (2007/10/02)
A simple synthesis of a new thirty two membered macrocycle including height oxygen atoms (four ether, four esters) is described.This compound is a structural model of macrotetrolid nactins (ionophorus natural antibiotics).
16. Ionophore vom Typ der 3-Oxapentadiamide
Pretsch, Erno,Ammann, Daniel,Osswald, Hans F.,Guggi, Marc,Simon, Wilhelm
, p. 191 - 196 (2007/10/02)
A series of lipophilic 3-oxapentane diamides were prepared and their selectivity in membranes was studied.N,N,N',N'-Tetracyclohexyl-3-oxapentane diamide forms 1:2- and 1:3-metal/ligand-complexes with Mg(2+) and Ca(2+) respectively and induces a selectivity in membranes for Ca(2+) over Mg(2+) by a factor of about 10E4.
