101 research outputs found
4-Methyl-2H-1,3-oxazine-2,6(3H)-dione
In the title compound, C5H5NO3, the planar (maximum deviation = 0.075 Å for the ring O atom) molecules form N—H⋯O hydrogen bonds in a zigzag chain (C—O⋯N bond angle ≃ 140°) between glide-related molecules
Tris(4-acetamidophenoxymethyl)methanol 0.7-hydrate
The asymmetric unit of the title compound, C28H31N3O7·0.7H2O, contains a molecule of tris(4-acetamidophenoxymethyl)methanol and 0.7 of a water molecule. An extensive hydrogen-bonding network includes interactions between all components of the crystal structure
4-Bromo-2H-1,3-oxazine-2,6(3H)-dione
The title compound, C4H2BrNO3, is one of a series of three substituted oxauracils prepared as precursors in the preparation of 1-aza-1,3-butadienes. Although each structure has identical potential for N—H⋯O intermolecular hydrogen bonds, each forms a distinctive intermolecular network. In the title compound, there are two independent molecules in the asymmetric unit, with a non-crystallographic twofold screw-like relationship between them. The two indpendent molecules are linked by an intermolecular N—H⋯O hydrogen bond. In the crystal structure, this hydrogen-bonded pair is linked to translationally related molecules through further intermolecular N—H⋯O hydrogen bonds, forming one-dimensional chains along [100]. The crystal structure also has short Br⋯O=C intermolecular contacts with distances of 2.843 (4) and 2.852 (4) Å
Control of Biohazards: A High Performance Energetic Polycyclized Iodine-Containing Biocide
The article of record as published may be found at http://dx.doi.org/10.1021/acs.inorgchem.8b01600Biohazards and chemical hazards as well as radioactive hazards have always been a threat to human health. The search for solutions to these problems is an ongoing worldwide effort. In order to control biohazards by chemical methods, a synthetically useful fused tricyclic iodine-rich compound, 2,6-diiodo-3,5-dinitro-4,9-dihydrodipyrazolo [1,5a:5',1'-d][1,3,5]triazine (5), with good detonation performance was synthesized, characterized, and its properties determined. This compound which acts as an agent defeat weapon has been shown to destroy certain microorganisms effectively by releasing iodine after undergoing decomposition or combustion. The small iodine residues remaining will not be deleterious to human life after 1 month.Financial support of the Office of Naval Research (N00014-16- 1-2089), and the Defense Threat Reduction Agency (HDTRA 1-15-1-0028) is gratefully acknowledged. The M. J. Murdock Charitable Trust (No. 2014120) is thanked for funds supporting the purchase of a 500 MHz NMR.Financial support of the Office of Naval Research (N00014-16- 1-2089), and the Defense Threat Reduction Agency (HDTRA 1-15-1-0028) is gratefully acknowledged. The M. J. Murdock Charitable Trust (No. 2014120) is thanked for funds supporting the purchase of a 500 MHz NMR
Hydrolytic Reactivity Trends among Potential Prodrugs of the O2-Glycosylated Diazeniumdiolate Family. Targeting Nitric Oxide to Macrophages for Antileishmanial Activity
Glycosylated diazeniumdiolates of structure R2NN(O)dNO-R ′ (R ′ ) a saccharide residue) are potential prodrugs of the nitric oxide (NO)-releasing but acid-sensitive R2NN(O)dNO- ion. Moreover, cleaving the acid-stable glycosides under alkaline conditions provides a convenient protecting group strategy for diazeniumdiolate ions. Here, we report comparative hydrolysis rate data for five representative glycosylated diazeniumdiolates at pH 14, 7.4, and 3.8-4.6 as background for further developing both the protecting group application and the ability to target NO pharmacologically to macrophages harboring intracellular pathogens. Confirming the potential in the latter application, adding R2NN(O)dNO-GlcNAc (where R2N) diethylamino or pyrrolidin-l-yl and GlcNAc) N-acetylglucosamin-l-yl) to cultures of infected mouse macrophages that were deficient in inducible NO synthase caused rapid death of the intracellular protozoan parasite Leishmania major with no host cell toxicity
Inhibition of Human Acetyl- and Butyrylcholinesterase by Novel Carbamates of (−)- and (+)-Tetrahydrofurobenzofuran and Methanobenzodioxepine
A new enantiomeric synthesis utilizing classical resolution provided two novel series of optically active inhibitors of cholinesterase: (−)- and (+)- O-carbamoyl phenols of tetrahydrofurobenzofuran and methanobenzodioxepine. An additional two series of (−)- and (+)-O-carbamoyl phenols of pyrroloindole and furoindole were obtained by known procedures, and their anticholinesterase actions were similarly quantified against freshly prepared human acetyl- (AChE) and butyrylcholinesterase (BChE). Both enantiomeric forms of each series demonstrated potent cholinesterase inhibitory activity (with IC50 values as low as 10 nM for AChE and 3 nM for BChE), with the exception of the (+)-O-carbamoyl phenols of pyrroloindole that lacked activity (IC50 values > 1 µM). Based on the biological data of these four series, a SAR analysis was provided by molecular volume calculations. In addition, a probable transition state model was established according to the known X-ray structure of a transition state complex of Torpedo californica AChE-m-(N,N,N,trimethylammonio)-2,2,2-trifluoroacetophenone (TcAChE-TMTFA). This model proved valuable in explaining the enantio-selectivity and enzyme subtype selectivity of each series. These carbamates are more or similarly potent to anticholinesterases in current clinical use; providing not only inhibitors of potential clinical relevance but also pharmacological tools to define drug-enzyme binding interactions within an enzyme crucial in the maintenance of cognition and numerous systemic physiological functions in health, aging and disease
Fluorescent Silicate Materials for the Detection of Paraoxon
Porphyrins are a family of highly conjugated molecules that strongly absorb visible light and fluoresce intensely. These molecules are sensitive to changes in their immediate environment and have been widely described for optical detection applications. Surfactant-templated organosilicate materials have been described for the semi-selective adsorption of small molecule contaminants. These structures offer high surface areas and large pore volumes within an organized framework. The organic bridging groups in the materials can be altered to provide varied binding characteristics. This effort seeks to utilize the tunable binding selectivity, high surface area, and low materials density of these highly ordered pore networks and to combine them with the unique spectrophotometric properties of porphyrins. In the porphyrin-embedded materials (PEMs), the organosilicate scaffold stabilizes the porphyrin and facilitates optimal orientation of porphyrin and target. The materials can be stored under ambient conditions and offer exceptional shelf-life. Here, we report on the design of PEMs with specificity for organophosphates and compounds of similar structure
A study of the structure–activity relationship of GABAA–benzodiazepine receptor bivalent ligands by conformational analysis with low temperature NMR and X-ray analysis
The stable conformations of GABAA-benzodiazepine receptor bivalent ligands were determined by low temperature NMR spectroscopy and confirmed by single crystal X-ray analysis. The stable conformations in solution correlated well with those in the solid state. The linear conformation was important for these dimers to access the binding site and exhibit potent in vitro affinity and was illustrated for α5 subtype selective ligands. Bivalent ligands with an oxygen-containing linker folded back upon themselves both in solution and the solid state. Dimers which are folded do not bind to Bz receptors
catena-Poly[[(tetrahydrofuran-κO)potassium]-di-μ-dimethylamido-κ4N:N-aluminium-di-μ-dimethylamido-κ4N:N-potassium-di-μ-dimethylamido-κ4N:N-aluminium-di-μ-dimethylamido-κ4N:N]
The title compound, [Al2K2(C2H6N)8(C4H8O)]n, formed during the sonochemical reaction between Al(NMe2)3 and sodium–potassium alloy in the presence of tetrahydrofuran (THF). Its asymmetric unit has two inequivalent K+ sites. One site is coordinated by a THF ligand, and crystallizes as a one-dimensional polymer with a backbone of catenated AlN2K rings. A twofold rotation axis bisects one K+ site and the THF ligand; the second K+ site is situated on an inversion centre, resulting in a planar four-coordination by N atoms. The latter symmetry operation generates the second half of the THF molecule and fills out the coordination sphere of the potassium sites. The chains extend along the c-axis direction and zigzag at the THF-coordinated K+ sites by an angle of 106.02 (5)°
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