55-86-7Relevant articles and documents
To be dinuclear or not: Z-DNA induction by nickel complexes
Spingier, Bernhard,Antoni, Philipp M.
, p. 6617 - 6622 (2007)
The left-handed Z-DNA has been identified as a gene regulating element. Therefore the generation of ZDNA through metal complexes might be an innovative way for the regulation of gene expression. Use of the new dinuclear complex N,N,N',N'-tetrakis-[2(3,5-dimethylpyrazol-l-yl)ethylJ-l,3propylenediamine- bis(nickel(II) dinitrate) (2) reversibly induced Z-DNA formation. However, when a 1:1 ratio of metal/dinucleating ligand was used as a control, the midpoint of the B- to Z-DNA transition was at the same nickel concentration as in case of the dinuclear complex. The novel mononuclear analogue, N-methyl-N,N-bis-[2(3,5- dimethylpyrazol-l-yl)ethyl]aminenickel(II)-dinitrate (3) was inducing the Z-DNA at a similar ratio versus nucleotides as free nickel(II) itself. For the first time, proton and nickel binding constants for the bis-[2-(pyrazol-lyl)ethyl] amine ligand system are reported and discussed. Both nickel complexes 2 and 3 were structurally characterized by single crystal analysis. Furthermore, the synthesis of the two new ligands, N,N,N',N,'-tetrakis-[2-(3,5-dimethylpyrazol-l- yl)ethyl]-l,2-propylenediamine (4) and N-methyl-N,N-bis-[2(3,5-dimethylpyrazol- l-yl)ethyl]amine (5) is described. The two major synthetic pathways leading to polypyrazoyl amines in general are critically discussed with respect to yield, reproducibility and handling of the intermediates.
Synthesis, structure, spectra and redox of Cu(II) complexes of chelating bis(benzimidazole) - Thioether ligands as models for electron transfer blue copper proteins
Vaidyanathan,Balamurugan,Sivagnanam,Palaniandavar
, p. 3498 - 3506 (2001)
The tridentate ligand 1,5-bis(benzimidazol-2-yl)-3-thiapentane (L1) with N2S donor set forms the complex [Cu(L1)-(H2O)Cl]Cl 1a and the linear quadridentate ligand 1,8-bis(benzimidazol-2-yl)-3,6-dithiaoctane (L2) with N2S2 donor set forms the complexes [Cu(L2)](ClO4)2·2H2O 2a and [Cu(L2)(NO3)]NO3 2b. The linear pentadentate ligand 1,11-bis(pyrid-2-yl)-3,6,9-trithiaundecane (L3) with N2S3 donor set forms the complex [Cu(L3)](ClO4)2 3. The perchlorate complex [Cu(L4)](ClO4)2·2CH3CN 4 of the pentadentate ligand,N,N-bis(benzimidazol-2-ylmethylthioethyl)methyl-amine (L4) with N3S2 donor set has also been isolated. In 1a Cu(II) is coordinated to the two benzimidazole nitrogens and thioether sulfur of the ligand L1, a chloride ion and a water molecule. The coordination geometry around copper is intermediate between trigonal bipyramidal and square pyramidal geometries and is better described as trigonal bipyramidal distorted square based pyramidal (TBDSBP) with the sulfur and nitrogen atoms and the chloride ion in the equatorial positions and the oxygen of water in the apical position. The coordination geometry around copper(II) in 2b is best described as trigonal bipyramidal, with both the thioether sulfur atoms [Cu-S(1), 2.529(5) and Cu-S(2), 2.438(6) A] and one of the oxygen atoms of the nitrate ion [Cu-O(1), 2.066(13) A] constituting the trigonal plane and both the benzimidazole nitrogens [Cu-N, 1.985(14) and 1.953(13) A] occupying the axial positions. The bulky benzimidazole moieties of the ligand prevent the other nitrate ion from coordinating and favours trigonal bipyramidal geometry in spite of the presence of two six-membered chelate rings. In 4 the coordination plane of Cu(II) is comprised of two benzimidazole nitrogens, one thioether sulfur and N-methyl substituted amine nitrogen atom with the other thioether sulfur atom coordinated axially. The coordination geometry is best described as trigonal bipyramidal distorted square based pyramidal (TBDSBP). The ligand field and EPR spectra of 1a, 2a and 2b are consistent with trigonal bipyramidal geometry in the solid state, whereas two ligand field bands in solution and an axial EPR spectrum in frozen solution were observed suggesting a change in coordination geometry to a square-based one on dissolution. The complexes 3 and 4 exhibit only one ligand field band in the solid state and axial EPR spectrum consistent with a square based geometry. All the complexes exhibit an intense S(σ)→Cu(II) CT band in the range 330-380 nm and a high positive CuII/CuI redox potential.
Mass spectral studies of silyl derivatives of partially hydrolyzed products of nitrogen mustards: Important markers of nitrogen mustard exposure
Chandra, Buddhadeb,Sinha Roy, Kanchan,Shaik, Mahabul,Waghmare, Chandrakant,Palit, Meehir
, (2020/01/21)
Rationale: Nitrogen mustards (NMs) are vesicant class of chemical warfare agents. From the viewpoint of the Chemical Weapons Convention partially hydrolyzed products of nitrogen mustards (pHpNMs) are considered as important markers of nitrogen mustard exposure. The detection of pHpNMs from biological or environmental samples is highly useful for obtaining forensic evidence of exposure to NMs. Methods: Gas chromatography interfaced with tandem mass spectrometry (GC/MS/MS) is a widely used tool for the identification and sensitive detection of metabolites of NMs in complex matrices. The pHpNMs were derivatized using silylating agents as they are highly polar and non-amenable to GC. The mass spectral studies of these silyl derivatives of pHpNMs were performed using GC/MS/MS in both electron ionization (EI) and chemical ionization (CI) mode. Results: Various approaches have been proposed to assess the fragmentation pathways of the trimethylsilyl (TMS) and tert-butyldimethylsilyl (TBDMS) derivatives of pHpNMs. All the proposed fragmentation pathways were based on the product and/or precursor ion scanning of corresponding ions in both EI and CI mode. In the case of EI, most of the fragmentation pathways involved either α-cleavage or inductive cleavage. Conclusions: This is the first report on the MS study of the silyl derivatives of pHpNMs. The study of the two different derivatives of pHpNMs using both EI- and CI-MS provides a reliable, unambiguous identification of pHpNMs in complex environmental and biomedical matrices (such as plasma and urine) during any verification activities.
Rational design of an organocatalyst for peptide bond formation
Handoko,Satishkumar, Sakilam,Panigrahi, Nihar R.,Arora, Paramjit S.
supporting information, p. 15977 - 15985 (2019/10/11)
Amide bonds are ubiquitous in peptides, proteins, pharmaceuticals, and polymers. The formation of amide bonds is a straightforward process: amide bonds can be synthesized with relative ease because of the availability of efficient coupling agents. However, there is a substantive need for methods that do not require excess reagents. A catalyst that condenses amino acids could have an important impact by reducing the significant waste generated during peptide synthesis. We describe the rational design of a biomimetic catalyst that can efficiently couple amino acids featuring standard protecting groups. The catalyst design combines lessons learned from enzymes, peptide biosynthesis, and organocatalysts. Under optimized conditions, 5 mol % catalyst efficiently couples Fmoc amino acids without notable racemization. Importantly, we demonstrate that the catalyst is functional for the synthesis of oligopeptides on solid phase. This result is significant because it illustrates the potential of the catalyst to function on a substrate with a multitude of amide bonds, which may be expected to inhibit a hydrogen-bonding catalyst.
COMPOSITIONS AND METHODS FOR THE TREATMENT OF SEVERE PAIN
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Paragraph 0109-0110, (2015/03/31)
The invention relates to the compounds of formula I or its pharmaceutical acceptable salts, as well as polymorphs, solvates, enantiomers, stereoisomers and hydrates thereof. The pharmaceutical compositions comprising an effective amount of compounds of formula I, and methods for the treatment of severe pain may be formulated for oral, buccal, rectal, topical, transdermal, transmucosal, intravenous, parenteral administration, syrup, or injection. Such compositions may be used to treatment of postoperative pain, cancer pain, kidney stones pain, fractures, local pain, chronic pain, chemotherapy induced pain, neuropathic pain, post herpetic neuralgia, neuralgia, motor neurone disease, diabetic neuropathy, postherpetic neuralgia, injury, post-operative pain, osteoarthritis, rheumatoid arthritis, multiple sclerosis, spinal cord injury, migraine, HIV related neuropathic pain, cancer pain and lower back pain.
