Substituted benzopyranopyridopyrimidine ring syntheses by the ternary condensation of malononitrile, salicylaldehyde, and aromatic ketones in the presence of ammonium acetate

1972 ◽  
Vol 37 (10) ◽  
pp. 1523-1526 ◽  
Author(s):  
Akio. Sakurai ◽  
Yoshito. Motomura ◽  
Hiroshi. Midorikawa
Keyword(s):  
Ammonium Acetate ◽  
Aromatic Ketones

Three-Component Reaction of Homophthalic Anhydride with Carbonyl Compounds and Ammonium Acetate: New Developments

Synthesis ◽  
2020 ◽  
Vol 52 (15) ◽  
pp. 2190-2195 ◽  
Author(s):  
Mikhail Krasavin ◽  
Alexander Safrygin ◽  
Olga Bakulina ◽  
Dmitry Dar’in
Keyword(s):  
Carbonyl Compounds ◽  
Ammonium Acetate ◽  
Cyclic Ketones ◽  
Aliphatic Aldehydes ◽  
New Developments ◽  
Aromatic Ketones ◽  
Three Component Reaction ◽  
Diastereomeric Mixture ◽  
Aqueous Base ◽  
Homophthalic Anhydride

The earlier described reaction of homophthalic anhydrides with aromatic ketones and ammonium acetate was tested for cyclic ketones (yielding spirocyclic motifs) and aliphatic aldehydes. In contrast to previous findings, the reaction was found to require no catalyst at all and to be applicable, in the non-catalyzed format, to these new carbonyl substrates as well as aromatic ketones. The reaction typically proceeds with high diastereoselectivity; if not, the initial diastereomeric mixture can be quantitatively equilibrated into a single, trans-diastereomer on treatment with aqueous base.

Oligophenylene 2,4,6-triarylpyridines and analogous diaza-p-terphenyls, diaza-p-quaterphenyls and diaza-p-quinquephenyls with luminiscent activity

1989 ◽  
Vol 54 (2) ◽  
pp. 462-472 ◽  
Author(s):  
Antonín Kurfürst ◽  
Pavel Lhoták ◽  
Miroslav Petrů ◽  
Josef Kuthan
Keyword(s):  
Spectral Region ◽  
Ammonium Acetate ◽  
Visible Spectral Region ◽  
Pyridinium Salts ◽  
Aromatic Ketones ◽  
Quaternary Pyridinium Salts

Cyclocondensation of α,β-unsaturated aromatic ketones V and VIII with quaternary pyridinium salts VI in the presence of ammonium acetate gave 2,4,6-triarylpyridines I, aryl-substituted diaza-p-terphenyls IIa,b, diaza-p-quaterphenyls IIc,d and diaza-p-quinquephenyls IIe,f. All the new polyphenylene compounds exhibit characteristic luminiscence in the visible spectral region.

Simple Selective Synthesis of 2,4- and 2,6-Diarylpyridines through Metal-Free Cyclocondensation of Aromatic Ketones with Ammonium Acetate

Synthesis ◽  
2010 ◽  
Vol 2010 (24) ◽  
pp. 4228-4234 ◽  
Author(s):  
Guosheng Huang ◽  
Jin Liu ◽  
Chuanxin Wang ◽  
Liansheng Wu ◽  
Fen Liang
Keyword(s):  
Ammonium Acetate ◽  
Selective Synthesis ◽  
Aromatic Ketones ◽  
Metal Free

The structure of pre-mRNA and mRNA from erythroid cells

1978 ◽  
Vol 36 (2) ◽  
pp. 234-235
Author(s):  
A.-M. Ladhoff ◽  
B.J. Thiele ◽  
Ch. Coutelle ◽  
S. Rosenthal
Keyword(s):  
Bone Marrow ◽  
Structural Transformation ◽  
Electron Micrographs ◽  
Ammonium Acetate ◽  
Bone Marrow Cells ◽  
Erythroid Cells ◽  
Globin Mrna ◽  
Ordered Structures ◽  
Rabbit Bone ◽  
Rabbit Reticulocytes

The suggested precursor-product relationship between the nuclear pre-mRNA and the cytoplasmic mRNA has created increased interest also in the structure of these RNA species. Previously we have been published electron micrographs of individual pre-mRNA molecules from erythroid cells. An intersting observation was the appearance of a contour, probably corresponding to higher ordered structures, on one end of 10 % of the pre-mRNA molecules from erythroid rabbit bone marrow cells (Fig. 1A). A virtual similar contour was observed in molecules of 9S globin mRNA from rabbit reticulocytes (Fig. 1B). A structural transformation in a linear contour occurs if the RNA is heated for 10 min to 90°C in the presence of 80 % formamide. This structural transformation is reversible when the denatured RNA is precipitated and redissolved in 0.2 M ammonium acetate.

Electron Microscopy of the Nucleic Acid of Mouse Mammary Tumor Virus

1968 ◽  
Vol 26 ◽  
pp. 22-23
Author(s):  
N. H. Sarkar ◽  
Dan H. Moore
Keyword(s):  
Mammary Tumor ◽  
Mouse Mammary Tumor Virus ◽  
Ammonium Acetate ◽  
Dry Weight ◽  
Mouse Tumor ◽  
Mammary Tumor Virus ◽  
Rna Molecules ◽  
Mouse Mammary Tumor ◽  
Tumor Virus ◽  
The Subject

Mouse mammary tumor virus (MTV) is believed to contain about 0.8% single stranded ribonucleic acid (RNA). This value of RNA content was estimated on a dry weight basis. The subject of this report is an attempt to visualize the RNA molecules of MTV particles.MTV particles were isolated from RIII mouse (tumor incidence approximately 80%) milk according to the method described by Lyons and Moore. Purified virions from 5 ml of milk were finally suspended in 0.2 ml of PBS, pH 7.4 and was mixed with an equal volume of pronase (5 mg/ml). This mixture was incubated at 37°C for an hour. RNA was extracted three times using freshly prepared cold phenol. It was then treated three times with cold ethyl ether to remove any trace of phenol. The RNA thus extracted was divided into two parts. One part was diluted four fold with 8M urea to avoid aggregation of the molecules. The other part was left untreated. Both samples were then mixed with an equal volume of 1M ammonium acetate, adjusted to pH 8.0 with NH3 containing chymotrypsin at a concentration of 0.01%.

HVEM Cryomicroscopy of Frozen Hydrated PTK1 Cells

1990 ◽  
Vol 48 (1) ◽  
pp. 500-501
Author(s):  
E.T. O’Toole ◽  
G.P. Wray ◽  
J.R. Kremer ◽  
J.R. Mcintosh
Keyword(s):  
Liquid Nitrogen ◽  
Phase Contrast ◽  
Culture Medium ◽  
Low Dose ◽  
Ammonium Acetate ◽  
Freezing Point ◽  
Voltage Electron ◽  
Cold Stage ◽  
Humidity Chamber ◽  
Coated Carbon

Ultrarapid freezing and cryomicroscopy of frozen hydrated material makes it possible to visualize samples that have never been exposed to chemical fixatives, dehydration, or stains. In principle, freezing and cryoimaging methods avoid artifacts associated with chemical fixation and processing and allow one to visualize the specimen in a condition that is close to its native state. Here we describe a way to use a high voltage electron microscope (HVEM) for the cryoimaging of frozen hydrated PTK1 cells.PTK1 cells were cultured on formvar-coated, carbon stabilized gold grids. After three days in culture, the grids were removed from the culture medium and blotted in a humidity chamber at 35° C. In some instances, the grids were rinsed briefly in 0.16 M ammonium acetate buffer (pH 7.2) prior to blotting. After blotting, the grids were transferred to a plunging apparatus and plunged into liquid ethane held directly above its freezing point. The plunging apparatus consists of a vertical slide rail that guides the fall of a mounted pair of forceps that clamp the specimen. The forceps are surrounded by a plexiglass humidity chamber mounted over a dewar of liquid nitrogen containing an ethane chamber. After freezing, the samples were transferred to liquid nitrogen and viewed in a JEOL JEM 1000 equipped with a top entry cold stage designed and built by Mr. George Wray (Univ. Colorado). The samples were routinely exposed to electron doses of 1 e/Å2/sec, and viewed at a temperature of −150° C. A GATAN video system was used to enhance contrast and to estimate the correct amount of underfocus needed to obtain phase contrast at various magnifications. Low dose micrographs were taken using two second exposures of Kodak 4463 film. The state of the solid water in the specimen was determined by diffraction using a 30/μm field limiting aperture and a camera length of 1 meter.

Synthesis of some Novel Imidazoles Catalyzed by Co3O4 Nanoparticles and Evaluation of their Antibacterial Activities

2018 ◽  
Vol 21 (4) ◽  
pp. 271-280 ◽  
Author(s):  
Mohammad A. Ghasemzadeh ◽  
Mohammad H. Abdollahi-Basir ◽  
Zahra Elyasi
Keyword(s):  
Cobalt Oxide ◽  
Ammonium Acetate ◽  
Reaction Times ◽  
Antibacterial Activities ◽  
Primary Amines ◽  
Oxide Nanoparticles ◽  
Co3o4 Nanoparticles ◽  
Cobalt Oxide Nanoparticles ◽  
Ft Ir ◽  
Tetrasubstituted Imidazoles

Aim and Objective: The multi-component condensation of benzil, primary amines, ammonium acetate and various aldehydes was efficiently catalyzed using cobalt oxide nanoparticles under ultrasonic irradiation. This approach describes an effective and facile method for the synthesis of some novel 1,2,4,5-tetrasubstituted imidazole derivatives with several advantages such as high yields and short reaction times and reusability of the catalyst. Moreover, the prepared heterocyclic compounds showed high antibacterial activity against some pathogenic strains. Materials and Method: The facile and efficient approaches for the preparation of Co3O4 nanoparticles were carried out by one step method. The synthesized heterogeneous nanocatalyst was characterized by spectroscopic analysis including EDX, FE-SEM, VSM, XRD and FT-IR analysis. The as-synthesized cobalt oxide nanoparticles showed paramagnetic behaviour in magnetic field. In addition, the catalytic influence of the nanocatalyst was examined in the one-pot reaction of primary amines, benzil, ammonium acetate and diverse aromatic aldehydes under ultrasonic irradiation. All of the 1,2,4,5-tetrasubstituted imidazoles were investigated and checked with m.p., 1H NMR, 13C NMR and FT-IR spectroscopy techniques. The antibacterial properties of the heterocycles were evaluated in vitro by the disk diffusion against pathogenic strains such as Escherichia coli (EC), Bacillus subtillis (BS), Staphylococcus aureus (SA), Salmonellatyphi (ST) and Shigella dysentrae (SD) species. Results: In this research cobalt oxide nanostructure was used as a robust and green catalyst in the some novel imidazoles. The average particle size measured from the FE-SEM image is found to be 20-30 nm which confirmed to the obtained results from XRD pattern. Various electron-donating and electron-withdrawing aryl aldehydes were efficiently reacted in the presence of Co3O4 nanoparticles. The role of the catalyst as a Lewis acid is promoting the reactions with the increase in the electrophilicity of the carbonyl and double band groups. To investigate the reusability of the catalyst, the model study was repeated using recovered cobalt oxide nanoparticles. The results showed that the nanocatalyst could be reused for five times with a minimal loss of its activity. Conclusion: We have developed an efficient and environmentally friendly method for the synthesis of some tetrasubstituted imidazoles via three-component reaction of benzil, primary amines, ammonium acetate and various aldehydes using Co3O4 NPs. The present approach suggests different benefits such as: excellent yields, short reaction times, simple workup procedure and recyclability of the magnetic nanocatalyst. The prepared 1,2,4,5-tetrasubstituted imidazoles revealed high antibacterial activities and can be useful in many biomedical applications.

LC–MS/MS Determination of Apigenin in Rat Plasma and Application to Pharmacokinetic Study

2020 ◽  
Vol 21 ◽  
Author(s):  
Shixing Zhu ◽  
Jiayuan Zhang ◽  
Zhihua Lv ◽  
Mingming Yu
Keyword(s):  
Formic Acid ◽  
Pharmacokinetic Study ◽  
Ammonium Acetate ◽  
Rat Plasma ◽  
Biological Properties ◽  
Plasma Samples ◽  
Supply Rate ◽  
Natural Plant ◽  
Ammonium Acetate Buffer

Background: Apigenin, a natural plant flavone, has been shown to possess a variety of biological properties. Objective: In this report, a highly selective and sensitive LC-MS/MS method was developed and validated for the determination of apigenin in rat plasma. Methods: Analysts were separated on the HSS T3 column (1.8 μm 2.1×100 mm) using acetonitrile and 0.1% formic acid in 2 mM ammonium acetate buffer at a supply rate of 0.200 mL/min as eluent in gradient model. Results: Plasma samples were treated by protein precipitation using acetonitrile for the recovery ranging from 86.5% to 90.1% for apigenin. The calibration curves followed linearity in the concentration range of 0.50-500 ng/mL. The inter-day and intra-day precisions at different QC levels within 13.1% and the accuracies ranged from -10.6% to 8.6%. Conclusion: The assay has been successfully applied to the pharmacokinetic study of apigenin in rats.

Selective α,α-Dibromination of Arylethanones with Copper(II) Bromide

2019 ◽  
Vol 16 (9) ◽  
pp. 700-704
Author(s):  
Jitander K. Kapoor ◽  
Loveena Arora ◽  
Om Prakash
Keyword(s):  
Ethyl Acetate ◽  
Heterogeneous System ◽  
Side Chain ◽  
Selective Synthesis ◽  
Aromatic Ketones

Various arylethanones including electron-rich aromatic ketones such as o-hydroxyacetophenone and its p-isomer underwent selective side-chain α,α-dibromination using a heterogeneous system consisting of four molar equivalents of copper(II) bromide in chloroform-ethyl acetate under reflux. This study provides the cleanest method for the selective synthesis of several synthetically useful α,α-dibromoketones which are otherwise difficult to prepare.

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