[1+1] and [2+2] crown ethers derived from N,N-bis(2-hydroxyalkylbenzyl)alkylamine and their inclusion phenomena with metal ions

N,N-bis(2-hydroxyalkylbenzyl)alkylamine (HBA) is a derivative obtained from a single time ring opening of benzoxazines. For HBA with methyl group at ortho and para positions, and at N atom, the reaction between this derivative and ditosylated compound gives [1+1] dibenzo-monoaza-crowns. For HBA without methyl group at ortho position, the compound gives [2+2] macrocyclic ethers. The studies on inclusion phenomena using Pedersen’s and molar ratio techniques clarify the alkali metal ion guest inclusion to be 2:1 for [2+2] and 5:2 for [1+1] macrocycles.     

Inclusion Compounds Formed from N,N-bis(2-hydroxybenzyl)alkylamine Derivatives and Transition Metal Ions via Molecular Assembly

A series of N,N-bis(2-hydroxybenzyl)alkylamine derivatives (1–5) have been found to form host–guest compounds with transition metal ions. The inclusion phenomena in solution are confirmed from the new peak at 415?nm observed by UV-Vis (ultraviolet-visible) spectroscopy and the aromatic and methylene peak shifts observed by ¹H NMR (proton nuclear magnetic resonance) spectroscopy. Comparative studies on 1–5 by liquid–liquid extraction studies suggest that the bulky group at the aza position of the derivatives obstructs the ion interaction resulting in the decrease in ion extraction ability. Inclusion depends on the interaction of the transition metal ions with the compounds 1–5 at the aza and hydroxyl groups as identified by the two-dimensional nuclear Overhauser enhancement technique (¹H–¹H NOESY). The results from Job's plot and electrospray ionization mass spectroscopy (ESIMS) imply molecular assembly of the host–guest system in a 2:1 ratio. Comparative studies among different ions, i.e., Cu²⁺, Zn²⁺ and Cd²⁺ suggest that the host–guest formation is effective when electron sharing is possible through the outer orbital of the transition metal ions. In the case of inclusion in the solid state, the FTIR (Fourier transform infrared) spectra show the changes in vibrational mode of the functional groups in host molecules whereas the X-ray diffraction (XRD) patterns suggest a change in the packing structure of the host molecules. After host–guest formation, the thermal stability of the host molecules decreases as a result of the change in the packing structure from a hydrogen-bonded network to one of ionic interaction with the guest.     

Selective interaction of N,N-bis(aminobenzyl)naphthalenediimides with fluoride anion

In this work, the optical properties of N,N-bis(aminobenzyl)naphthalenediimides 2a–2d (BzNDIs) and their interaction with fluoride were studied. The results demonstrated that the amino group position in the benzyl substituent exerts an effect in the absorption and emission properties. Particularly, the N,N-bis(2-aminobenzyl)NDI 2b presented non-typical absorption and emission bands which indicate an intramolecular charge transfer from the amino phenyl group to the NDI core. As the concentration of 2b increases, the solution turns from colourless to a pale orange colour. The interaction of BzNDIs 2a–2d with anions was selective towards fluoride and the affinity was in the order para > ortho > meta with respect to the position of the amino group in the aminophenyl ring. Interestingly, the colour change in the solution of 2b upon addition of fluoride makes it a good candidate for a fluoride colorimetric detection. The voltammetry analysis indicates the ability of these molecules to accept two electrons, in consequence the interaction of two fluoride anions with the BzNDIs was observed.     

N,N-bis (2-chloroethyl) amides and N,N-bis(2-chloroethyl) hydrazides of carboxylic acids of the furan series

Reaction of N, N-bis(2-chloroethyl)amine hydrochloride with chloroanhydrides of carboxylic acids of the furan series, in chloroform in the presence of pyridine gives N, N-bis(2-chloroethyl)amides of furan carboxylic acid, furylacrylic acid, 5-nitrofuran carboxylic acid, and 5-nitrofurylacrylic acid.N, N-bis(2-chloroethyl)hydrazides of furan carboxylic acid, furyl carboxylic acid, 5-nitrofuran carboxylic acid, and 5-nitrofurylacrylic acid were obtained in 78–88% yields by reacting N, N-bis(2-chloroethyl)hydrazine hydrochloride with the chloroanhydrides of the appropriate acids in chloroform in the presence of pyridine. The last two hydrazides were prepared in 31 % and 56 % yield, respectively, using anhydrous sodium acetate in place of pyridine.     

N,N-二(2-羟乙基)-2-氨基乙磺酸钠的合成研究

采用二乙醇胺与2-氯乙基磺酸钠反应合成N,N-二(2-羟乙基)-2-氨基乙磺酸钠(BES钠盐),由核磁氢谱(1H NMR)和碳谱(13C NMR)、红外光谱(FT-IR)、X射线衍射(XRD)等仪器表征了合成产物的结构和特性.根据反应体系pH值的变化及核磁谱图,确定了BES钠盐的最佳合成工艺:反应物料比为1:1:1,反...     

Optimized DNA targeting using N,N-bis(2-pyridylmethyl)-beta-alanyl 2'-amino-LNA

Incorporation of N,N-bis(2-pyridylmethyl)-beta-alanyl 2'-amino-LNA (bipyridyl-functionalized 2'-amino locked nucleic acid) monomers into DNA strands enables high-affinity targeting of complementary DNA with excellent Watson-Crick selectivity in the presence of divalent metal ions. Positioning of bipyridyl-functionalized 2'-amino-LNA monomers in two complementary DNA strands in a "3'-end zipper" constitution allows modulation of duplex stability, i.e., a strong stabilizing effect with one equivalent of divalent metal ion per bipyridyl pair, or a strong destabilizing effect with an excess of divalent metal ions.     

A comparative study of chromium(III) ion-selective electrodes based on N,N-bis(salicylidene)-o-phenylenediaminatechromium(III)

A comparative study was made between three types of Cr(III) ion-selective electrodes: PVC membrane electrode, silver coated electrode and modified carbon paste electrode based on N,N-bis(salicylidene)-o-phenylenediaminatechromium(III) complex (Crsalophen). As anticipated, electrodes with a solid contact, rather than a traditional liquid inner contact, give lower detection limits because of diminished ion fluxes. Often, however, ill-defined solid contact gives rise to instabilities and interferences by oxygen gas. The carbon paste electrode provides a more sensitive and stable device than that afforded by PVC and coated electrodes. The best performance was obtained by an electrode based on the paste containing 3.5 wt% Cr-complex, 48.5% graphite plasticized with a mixture of 24.0 wt% tris(2-ethylhexyl) phosphate (DOPh) + 24.0 wt% dioctyl sebacate (DOS). The sensor has a linear dynamic range of 7.5 × 10^-6 to 1.0 × 10^-2 M, with a Nernstian slope of 20.1 ± 0.6 mV decade^-1, and a detection limit of 1.8 × 10^-6. It has a short response time of a bout 8 s and is applicable in a pH range of 4.5-7.7. It was successfully used as an indicator electrode in potentiometric titration of Cr(III) with EDTA and in determination of Cr(III) in water samples and chromium in (Crsalophen).     

An Effective Route to N,N-bis (2,3-Epoxypropyl) 2-F-Alkylethylamines

An effective procedure is described for the synthesis of N,N-Bis (epoxypropyl) 2-F-alkylethylamines avoiding the formation of 2-F-alkylethylethenes usually occuring in the N-alkylation of 2-F-alkylethyl iodides by amines.     

Synergistic effects of a specific metal template and H-bonds in controlling macrocyclization: a simple, selective, and effective cyclization from N,N-bis(2-hydroxybenzyl)alkylamine derivatives

A macrocyclic compound obtained from a simple, selective, and effective reaction between N,N-bis(2-hydroxybenzyl)alkylamine derivatives and 1,3-bis(tosyloxy)propane is a good example of a cyclization controlled by synergistic effects of a metal template and hydrogen bonds.     

Crystal structure of copper(II) complex with N,N-bis(2-benzimidazolylmethyl)benzylamine

The copper(II) complex with N,N-bis(2-benzimidazolylmethyl)benzylamine has been synthesized and its crystal structure was determined by X-ray diffraction methods.     

Crystal Structure of 1，2：5，6－Di－O－isopropylidene－α－D－glucofuranosyl N，N－bis（2－chloroethyl） Phosphordiamidate

ＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆ１，２：５，６－Ｄｉ－Ｏ－ｉｓｏｐｒｏｐｙｌｉｄｅｎｅ－α－Ｄ－ｇｌｕｃｏｆｕｒａｎｏｓｙｌＮ，Ｎ－ｂｉｓ（２－ｃｈｌｏｒｏｅｔｈｙｌ）ＰｈｏｓｐｈｏｒｄｉａｍｉｄａｔｅＣｈｅｎＲｕ－Ｙｕ；ＣｈｅｎＸｉａｏ－Ｒｕ（...     

Reductive bromination of N,N-bis(4-tert-butylphenyl)hydroxylamine

Russian Chemical Bulletin - Unlike most arenes, N, N-bis(4-tert-butylphenyl)hydroxylamine reacts with Br2via the reductive bromination mechanism. Here, two hydrogens in ortho positions of benzene...     

Structure and stereodynamics of N,N-bis(silyloxy)enamines

The structure and stereodynamics of N,N-bis(silyloxy)enamines (1), a new class of enamines with extraordinary reactivity, have been simulated by the DFT PBE/TZP method. The computed pattern of dynamic behavior and structural peculiarities of 1 was shown to reflect adequately the results of the studies by a series of physical methods including X-ray analysis and dynamic NMR and UV spectroscopies, which provided evidence of a rather low barrier for rotation around the C,N single bond, a negligible contribution of the n-pi-conjugation, a high barrier of inversion, and high pyramidality of the nitrogen atom.     

Synthesis of saccharidyl N,N-bis(2-chloroethyl)phosphoramidates and their antitumor activity

In order to search for novel antitumor drugs with high activity and low toxicity, a series of new compounds, galactopyranosyl (or glucofuranosyl) N,N-bis(2-chloroethyl) phosphoramidates, have been synthesized. The structures of all compounds prepared were proved by ¹H NMR, ³¹P NMR, IR, and MS spectroscopy and by elemental analyses. The existence of diastereoisomers was detected by ³¹P NMR and ¹H NMR spectra. One of the two isomers of 3a and also one of 4b , i.e., 3a′ and 4b′ , respectively, were obtained by recrystallization. The absolute configurations of 3a′ and 4b′ were determined by single-crystal X-ray diffraction analysis. The results of the preliminary biological tests indicated that some of these compounds have certain inhibitory activities against L₁₂₁₀ cells.     

N-to-C sequential ligation using peptidyl N,N-bis(2-mercaptoethyl)amide building blocks

A novel N- to C-terminus sequential chemical ligation approach has been developed for protein synthesis. Key to this strategy is the relative stability of the N,N-bis(2-mercaptoethyl)amide (BMEA) to the conventional conditions of native chemical ligation. We have also found a new thiol additive for the BMEA-mediated ligation reaction. The usefulness of this approach was demonstrated in the syntheses of a medium-sized peptide and ubiquitin.