- THE APPLICATION OF ULTRASOUND TO N-METHYLATION OF DIAZACORONANDS
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The application of ultrasound to N-methylation of variety of diazacoronands by methyl iodide under phase transfer conditions leads to N,N'-dimethyl diazacoronands in almost quantitative yields.
- Jurczak, Janusz,Ostaszewski, Ryszard
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- Cycloaddition reactivity studies of first-row transition metal-azide complexes and alkynes: An inorganic click reaction for metalloenzyme inhibitor synthesis
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The studies described herein focus on the 1,3-dipolar cycloaddition reaction between first-row transition metal-azide complexes and alkyne reagents, i.e. an inorganic variant of the extensively used "click reaction". The reaction between the azide complexes of biologically-relevant metals (e.g., Fe, Co and Ni) found in metalloenzyme active sites and alkyne reagents has been investigated as a proof-of-principle for a novel method of developing metalloenzyme triazole-based inhibitors. Six Fe, Co and Ni mono-azide complexes employing salen- and cyclam-type ligands have been synthesized and characterized. The scope of the targeted inorganic azide-alkyne click reaction was investigated using the electron-deficient alkyne dimethyl acetylenedicarboxylate. Of the six metal-azide complexes tested, the Co and Ni complexes of the 1,4,8,11-tetrametyl-1,4,8,11-tetraazacyclotetradecane (Me 4cyclam) ligand showed a successful cycloaddition reaction and formation of the corresponding metal-triazolate products, which were crystallographically characterized. Moreover, use of less electron deficient alkynes resulted in a loss of cycloaddition reactivity. Analysis of the structural parameters of the investigated metal-azide complexes suggests that a more symmetric structure and charge distribution within the azide moiety is needed for the formation of a metal-triazolate product. Overall, these results suggest that a successful cycloaddition reaction between a metal-azide complex and an alkyne substrate is dependent both on the ligand and metal oxidation state, that determine the electronic properties of the bound azide, as well as the electron deficient nature of the alkyne employed.
- Evangelio, Emi,Rath, Nigam P.,Mirica, Liviu M.
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p. 8010 - 8021
(2012/08/08)
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- Composition, synthesis and therapeutic applications of polyamines
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This invention relates to a process of synthesis and composition of open chain (ring), closed ring, linear branched and or substituted polyamines, polyamine derived tyrosine phosphatase inhibitors and PPAR partial agonists/partial antagonists via a series of substitution reactions and optimizing the bioavailability and biological activities of the compounds. Polyamines prevent the toxicty of neutoxins and diabetogenic toxins including paraquat, methyphenyl pyridine radical, rotenone, diazoxide, streptozotocin and alloxan. These polyamines can be to treat neurological, cardiovascular, endocrine acquired and inherited mitochondrial DNA damage diseases and other disorders in mammalian subjects, and more specifically to the therapy of Parkinson's disease, Alzheimer's disease, Lou Gehrig's disease, Binswanger's disease, Olivopontine Cerebellar Degeneration, Lewy Body disease, Diabetes, Stroke, Atherosclerosis, Myocardial Ischemia, Cardiomyopathy, Nephropathy, Ischemia, Glaucoma, Presbycussis, Cancer, Osteoporosis, Rheumatoid Arthritis, Inflammatory Bowel Disease, Multiple Sclerosis and as Antidotes to Toxin Exposure.
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- Composition, synthesis and therapeutic applications of polyamines
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The invention relates to the preparation of novel polyamines, such as derivatives of 1,3-bis-[(2′-aminoethyl)-amino]propane (2,3,2-tetramine) and 1,4,8,11-tetraazacyclotetradecane (cyclam), which can be used to treat mitochondrial and degenerative diseases. Accordingly, in one aspect the invention is directed to compounds of the formula: wherein R1, R2, R3, R4, R5 and R6 may be the same or different and are hydrogen, alkyl, aryl, cycloalkyl, amino acid, glutathione, urate, ascorbate, estrogen, dehydroepiandrosterone, redox stabilizing substituents, a quinone, glutamate, succinate, —(CH2)n[XCH2)n]NH2— wherein n=3-6 and X=nitrogen, sulfur, phosporous or carbon, or heterocycle wherein R1 to R6 taken together are —(CH2XCH2)n— wherein n=3-6 and X=nitrogen, sulfur, phosporous or carbon. M, n, and p may be the same or different and are bridging groups of variable length from 3-12 carbons. X1 and X2 may be the same or different and are nitrogen, sulfur, phosporous or carbon.
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- Method for preparing alkoxyamines from nitroxides
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The invention relates to a process for preparing alkoxyamines. This process consists in mixing, in an organic solvent, a metal salt, a ligand for the metal, a halocarbon compound ZX and a nitroxide, in keeping the reaction medium stirring at a temperature of between 20° C. and 90° C. until the nitroxide has disappeared, in recovering the organic phase, in washing it with water and then in isolating the alkoxyamine by evaporating the organic solvent under reduced pressure.
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- Coordination to RMg+ and RZn+ cations
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Addition of a second coordinating agent (coord*) to a solution of RM(coord)+A- (R = ethyl or neopentyl, M = Zn or Mg, A- = 1,2,3,4-tetraphenylcyclopentadienyl) can provide equilibrium mixtures of these compounds, coord, and RM(coord*)+A-. This exchange with RMg(coord)+ requires the addition of a small amount of R2Mg, but added R2Zn is not necessary for exchanges with RZn(coord)+. The equilibrium constants provide information about the relative abilities of different coordinating agents to coordinate to RM+ and reveal significant differences between coordination to RMg+ and RZn+. Reactions of RM(coord)+ with R′2M (R = ethyl or neopentyl for RMg(coord)+ and ethyl, isopropyl, tert-butyl, neopentyl, or p-methylphenyl for RZn(coord)+) provide equilibrium mixtures of these components, R′M(coord)+, and R2M. The equilibrium constants provide information about the effect of R on stability. An X-ray structure of p-methylphenylzinc(2,5,8,11-tetramethyl-2,5,8,11-tetraazadodecane)+ shows that just three of the N atoms are coordinated to Zn. The effects of coord, R, and metal on RM(coord)+ stability are discussed, and the abilities of coordinating agents to coordinate to RM+, to slow allylic isomerization of (CH2 double bond CMeCH2)2Zn, and to convert R2Zn to RZn(coord)+ are compared.
- Tang, Hui
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p. 4810 - 4819
(2008/10/08)
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- New synthesis of trans-disubstituted cyclam macrocycles - Elucidation of the disubstitution mechanism on the basis of x-ray data and molecular modeling
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A new way to synthesize trans-disubstituted cyclam tetraazamacrocycles 1 is reported. The synthesis proceeds in three steps via the tricyclic 1,4,8,11-tetraazatricyclo-[9.3.1.14,8]hexadecane system 2, which can be selectively dialkylated and hydrolyzed under basic conditions to give the final product 1. An understanding of the reactivity, based on the X-ray experimental electrostatic potential and molecular modeling of the 1,4,8,11-tetraazatricyclo-[9.3.1.14,8]hexadecane macrotricycle, has permitted the elucidation of a new reaction pathway leading to the trans-disubstituted cyclam.
- Royal, Guy,Dahaoui-Gindrey, Valérie,Dahaoui, Slimane,Tabard, Alain,Guilard, Roger,Pullumbi, Pluton,Lecomte, Claude
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p. 1971 - 1975
(2007/10/03)
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- AFFINITIES OF CROWN ETHERS, GLYMES, AND POLYAMINES FOR ALKALI PICRATES IN TOLUENE. APPLICATION OF POLYMER-SUPPORTED LINEAR POLYETHERS.
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This work reports the measurements of K values for polyamines, glymes, a few glycols (including that of a long-chain polyethylene glycol, carbowax 6000), and some frequently used cation-binding ligands as complexers of lithium or sodium picrate in toluene as solvent. K values for different resins obtained with the same soluble ligand provide a comparison of the effectiveness of these resins in binding ionic solutes.
- Xu,Smid
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p. 3790 - 3796
(2007/10/02)
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