574-98-1Relevant articles and documents
Synthesis of lariat diazacrown ethers with terminal amino groups in the side chains
Lukyanenko,Kirichenko,Shcherbakov
, p. 343 - 350 (2004)
Treatment of diazacrown ethers with N-(haloalkyl)- and N-(haloethoxy) phthalimides gives the corresponding N,N′- substituted diazacrown ether. Hydrazinolysis of the latter then gives diazacrown ethers with terminal primary amino groups in the side chain. Their reductive methylation using formaldehyde in formic acid gives the dimethylamino derivatives. The presence of a lariat effect was demonstrated by treating the compounds obtained with picrates of alkali and alkaline-earth metals.
Lanthanide(iii) complexes of aminoethyl-DO3A as PARACEST contrast agents based on decoordination of the weakly bound amino group
Krchova, Tereza,Kotek, Jan,Jirak, Daniel,Havlickova, Jana,Cisarova, Ivana,Hermann, Petr
, p. 15735 - 15747 (2013)
2-Aminoethyl DOTA analogues with unsubstituted (H3L 1), monomethylated (H3L2) and dimethylated (H3L3) amino groups were prepared by improved synthetic procedures. Their solid-state structures exhibit an extensive system of intramolecular hydrogen bonds, which is probably present in solution and leads to the rather high value of the last dissociation constant. The protonation sequence of H3L1 in solution corresponds to that found in the solid state. The stability constants of the H3L1 complexes with La3+ and Gd3+ (20.02 and 22.23, respectively) are similar to those of DO3A and the reduction of the pK A value of the pendant amino group from 10.51 in the free ligand to 6.06 and 5.83 in the La3+ and Gd3+ complexes, respectively, points to coordination of the amino group. It was confirmed in the solid state structure of the [Yb(L1)] complex, where disorder between the SA′ and TSA′ isomers was found. A similar situation is expected in solution, where a fast equilibration among the isomers hampers the unambiguous determination of the isomer ratio in solution. The PARACEST effect was observed in Eu(iii)-H3L1/H3L2 and Yb(iii)-H3L1/H3L2 complexes, being dependent on pH in the region of 4.5-7.5 and pH-independent in more alkaline solutions. The decrease of the PARACEST effect parallels with the increasing abundance of the complex protonated species, where the pendant amino group is not coordinating. Surprisingly, a small PARACEST effect was also observed in solutions of Eu(iii)/Yb(iii)-H3L3 complexes, where the pendant amino group is dimethylated. The effect is detectable in a narrow pH region, where both protonated and deprotonated complex species are present in equilibrium. The data points to the new mechanism of the PARACEST effect, where the slow coordination-decoordination of the pendant amine is coupled with the fast proton exchange between the free amino group and bulk water mediates the magnetization transfer. The pH-dependence of the effect was proved to be measurable by MRI and, thus, the complexes extend the family of pH-sensitive probes. This journal is The Royal Society of Chemistry 2013.
Tuning DNA Supramolecular Polymers by the Addition of Small, Functionalized Nucleobase Mimics
Lachance-Brais, Christophe,Hennecker, Christopher D.,Alenaizan, Asem,Luo, Xin,Toader, Violeta,Taing, Monica,Sherrill, C. David,Mittermaier, Anthony K.,Sleiman, Hanadi F.
supporting information, p. 19824 - 19833 (2021/11/30)
Nucleobase mimicking small molecules able to reconfigure DNA are a recently discovered strategy that promises to extend the structural and functional diversity of nucleic acids. However, only simple, unfunctionalized molecules such as cyanuric acid and melamine have so far been used in this approach. In this work, we show that the addition of substituted cyanuric acid molecules can successfully program polyadenine strands to assemble into supramolecular fibers. Unlike conventional DNA nanostructure functionalization, which typically end-labels DNA strands, our approach incorporates functional groups into DNA with high density using small molecules and results in new DNA triple helices coated with alkylamine or alcohol units that grow into micrometer-long fibers. We find that small changes in the small molecule functional group can result in large structural and energetic variation in the overall assembly. A combination of circular dichroism, atomic force microscopy, molecular dynamics simulations, and a new thermodynamic method, transient equilibrium mapping, elucidated the molecular factors behind these large changes. In particular, we identify substantial DNA sugar and phosphate group deformations to accommodate a hydrogen bond between the phosphate and the small-molecule functional groups, as well as a critical chain length of the functional group which switches this interaction from intra- to interfiber. These parameters allow the controlled formation of hierarchical, hybrid DNA assemblies simply through the addition and variation of small, functionalized molecules.
Synthesis of hydroxyethyl methyl morpholinium azide (HEM Morph)N3: A highly efficient new task specific azide-based ionic liquid and its dual application as an azide source and media for synthesis of some novel aromatic O-oxime ethers-1,2,3-triazole conjugates as a potential antihistaminic agents
Rad, Mohammad Navid Soltani,Behrouz, Somayeh,Saremi, Hossein,Mohammadtaghi-Nezhad, Javad
, (2019/12/27)
The synthesis, characterization and application of hydroxyethyl methyl morpholinium azide (HEM Morph)N3 as a new azide-based ionic liquid (ABIL) has been described. (HEM Morph)N3 is used as a source of azide and reaction media for three components ‘Click’ Huisgen cycloaddition reaction between O-propargyl oxime ether and alkyl bromide to acquire novel aromatic O-oxime ethers-1,2,3-triazole conjugates as potential antihistaminic agents in good yields. The influence of parameters like temperature, amount of IL, type of azide-based ionic liquids and its reusability is investigated. The (HEM Morph)N3 is proved to be an efficient, thermally stable, inexpensive and recyclable azide-based ionic liquid which can be easily synthesized and used as both azide's source and reaction media for ‘Click’ Huisgen cycloaddition reaction.