2466-76-4Relevant articles and documents
-
Brinigar,Knaff
, p. 406 (1965)
-
Silica Subsurface Amine Effect on the Chemical Stability and Chromatographic Properties of End-Capped Immobilized Artificial Membrane Surfaces
Invergo, Ben,Alvarez, Francisco M.
, p. 1851 - 1860 (1991)
The silica surface of immobilized artificial membranes containing phosphatidylcholine (IAM.PC) has approximately two aminopropyl groups per immobilized phosphatidylcholine molecule.Primary amines near the silica subsurface adsorb biomolecules and also decrease the chemical stability of IAM.PC surfaces.Consequently, subsurface amines were end-capped by several methods including silylating reagents, acetyl analogues, glycidol, methyl glycolate, short-chain anhydrides (3-6 carbons/anhydride chain), and long-chain anhydrides (10-12 carbons/anhydride chain).All end-capping reactions resulted in loss of the initially immobilized phosphatidylcholine molecule.However, the amount of PC loss during end capping was very low (for alkyl anhydride end-capping reactions).After end capping, IAM.PC showed increased chemical stability compared to non end-capped IAM.PC surfaces.The chemical stability of IAM packing material was monitored by phospholipid leaching from IAM surfaces exposed to organic and aqeous solvents using thin-layer chromatography, 1H-NMR spectroscopy, infrared spectroscopy, and mass spectroscopy.IAM.PC packing material end capped with long-chain anhydrides exhibited the greatest chemical stability, i. e., little or no detectable phospholipid leaching when challenged with aqueous and/or organic solvents.The chromatography of acidic and basic compounds of end-capped and non end-capped IAM.PC surfaces was studied.Compared to non end-capped IAM.PC HPLC columns, the chromatographic retention times of acidic compounds (deoxynucleotides) decreased after end caping.In contrast, the retention times of basic compounds (amphetamine analogues) increased on end-capped IAM.PC HPLC columns.This indicates that these solutes have access to the silica subsurface amine during chromatography.
Synthesis, characterization and spectroscopic studies of two new 1-acetyl-3-alkylimidazolium ionic liquids
Huanhuan, Xu,Wenjuan, Zhu,Pingmei, Wang,Dafei, Wang,Qiang, Li
, p. 179 - 181 (2013)
Two new functionalized ionic liquids, 1-acetyl-3-alkylimidazolium iodides, were synthesized by the reactions of 1-acetylimidazole with alkyl iodides under solvent-free condition. Their structures were confirmed by 1H NMR, ESI-MS, IR, UV-Vis and elemental analysis. The 1-acetyl-3-ethylimidazolium iodide (3a) is a solid and 1-acetyl-3-hexylimidazolium iodide (3b) is a viscous liquid at room temperature.
DNA AFFINITY CLEAVING SEQUENCE SPECIFIC CLEAVAGE OF DNA BY DISTAMYCIN-EDTA*Fe(II) AND EDTA-DISTAMYCIN*Fe(II)
Taylor, John S.,Schultz, Peter G.,Dervan, Peter B.
, p. 457 - 465 (1984)
The attachment of EDTA*Fe(II) to distamycin changes the sequence specific DNA binding antibiotic into a sequence specific DNA cleaving molecule.We report the synthesis of EDTA-distamycin (ED) which has the metal chelator, EDTA, tethered to the carboxy terminus of the N-methylpyrrole tripeptide moiety of the antibiotic, distamycin.EDTA-distamycin*Fe(II) (ED*Fe(II)) at 1E-6M concentration efficiently cleaves pBR322 DNA (1E-5M in base pairs) in the presence of oxygen and dithiothreitol (DTT).Using Maxam-Gilbert sequencing gel analyses, we find that ED*Fe(II) affords DNA cleavage patterns of unequal intensity covering two to four contiguous base pairs adjacent to a five base pair site consisting of adenines (A) and thymines (T).The multiple cleavages at each site might be evidence for a diffusible oxidizing species, perhaps hydroxyl radical.The unequal intensity of cleavage on each side of the A + T site permit assignment of major and minor orientations of the tripeptide binding unit.A comparison of the cleavage specificity of ED*Fe(II) with distamycin-EDTA*Fe(II), (DE*Fe(II)) which has EDTA*Fe(II) attached to the amino terminus of the N-methylpyrrole tripeptide, shows DNA cleavage patterns at the same sites but with intensities of opposite polarity.Maxam-Gilbert sequencing gel analysis of the DNA cleavage patterns by ED*Fe(II) and DE*Fe(II) on both DNA strands of a 381 base pair restriction fragment reveals asymmetric DNA cleavage patterns.Cleavage is shifted to the 3' side of each DNA strand.A model consistent with this cleavage pattern indicates one preferred binding site for ED*Fe(II) and DE*Fe(II) is 3'-TTTAA-5' with the "amino end" of the tripeptide oriented to the 3' end of the thyamine rich strand.This "DNA affinity cleavage" method which consists of attaching cleaving functions to DNA binding molecules followed by DNA cleavage pattern analyses using Maxam-Gilbert sequencing gels may be a useful direct method for determining the binding site and orientation of small molecules on native DNA.
An efficient catalytic method for the c-n acylation of heterocycles by schiff base co(Ii), ni(ii), cu(ii) and zn(ii) transition metal complexes
Hegade, Sujit,Gaikwad, Gautam,Jadhav, Yuvraj,Chavan, Sanjay,Mulik, Ganpatrao
, p. 611 - 616 (2021/09/30)
The catalytic activity of Schiff base Co(II), Ni(II), Cu(II) and Zn(II) transition metal complexes was tested for N-Acylation of heterocycles with acetyl chloride. It is observed that all the complexes worked as efficient catalysts. The structural type of complexes was studied by an X-ray powder diffractogram (XRD). The mixed ligand complexes with PPh3 ligand show greater activity as compared to Phen complexes and Schiff base complexes. Especially complex [Ni(L)(PPh3)2Cl2] efficiently worked as a catalyst because of high thermal stability (TGA-DSC) and large catalytic surface area (BET).
Length-Selective Synthesis of Acylglycerol-Phosphates through Energy-Dissipative Cycling
Bonfio, Claudia,Caumes, Cécile,Duffy, Colm D.,Patel, Bhavesh H.,Percivalle, Claudia,Tsanakopoulou, Maria,Sutherland, John D.
supporting information, p. 3934 - 3939 (2019/03/08)
The main aim of origins of life research is to find a plausible sequence of transitions from prebiotic chemistry to nascent biology. In this context, understanding how and when phospholipid membranes appeared on early Earth is critical to elucidating the prebiotic pathways that led to the emergence of primitive cells. Here we show that exposing glycerol-2-phosphate to acylating agents leads to the formation of a library of acylglycerol-phosphates. Medium-chain acylglycerol-phosphates were found to self-assemble into vesicles stable across a wide range of conditions and capable of retaining mono- and oligonucleotides. Starting with a mixture of activated carboxylic acids of different lengths, iterative cycling of acylation and hydrolysis steps allowed for the selection of longer-chain acylglycerol-phosphates. Our results suggest that a selection pathway based on energy-dissipative cycling could have driven the selective synthesis of phospholipids on early Earth.
Imidazolium chloride: An efficient catalyst for transamidation of primary amines
Tian, Qingqiang,Gan, Zongjie,Wang, Xuetong,Li, Dan,Luo, Wen,Wang, Huajun,Dai, Zeshu,Yuan, Jianyong
supporting information, (2018/09/10)
A highly efficient and convenient protocol of imidazolium chloride (30 mol %) catalyzed amidation of amines with moderate to excellent yields was reported. The protocol shows broad substrate scope for aromatic, aliphatic, and heterocyclic primary amines.
