Regiocontrolled synthesis of 2,4,6-triarylpyridines from methyl ketones, electron-deficient acetylenes and ammonium acetate

2021 ◽  
Vol 19 (12) ◽  
pp. 2703-2715 ◽  
Author(s):  
Dmitrii A. Shabalin ◽  
Marina Yu. Dvorko ◽  
Elena Yu. Schmidt ◽  
Boris A. Trofimov
Keyword(s):  
Ammonium Acetate ◽  
Methyl Ketones ◽  
Simple Method ◽  
Regiocontrolled Synthesis

A simple method to access unsymmetrical 2,4,6-triarylpyridines starting from available methyl ketones and electron-deficient acetylenes was developed.

Iron-Catalyzed Domino Decarboxylation-Oxidation of ,-Unsaturated Carboxylic Acids Enabled Aldehyde C−H Methylation

2021 ◽  
Author(s):  
Pei-Xue Gong ◽  
Fangning Xu ◽  
Lu Cheng ◽  
Xu Gong ◽  
Jie Zhang ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Methyl Ketones ◽  
Simple Method ◽  
Unsaturated Carboxylic Acids

A practical and general iron-catalyzed domino decarboxylation-oxidation of ,-unsaturated carboxylic acids enabled aldehyde C−H methylation for the synthesis of methyl ketones has been developed. This mild, operationally simple method uses...

Reactions of Methyl Ketones and (Hetero)arylcarboxamides with N,N-Dimethylacetamide Dimethyl Acetal. A Simple Metal-Free Synthesis of 2,4,6-Trisubstituted Pyridines

2015 ◽  
Vol 68 (2) ◽  
pp. 184 ◽  
Author(s):  
Benjamin Prek ◽  
Uroš Grošelj ◽  
Marta Kasunič ◽  
Silvo Zupančič ◽  
Jurij Svete ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Single Crystal ◽  
Ammonium Acetate ◽  
Dimethyl Acetal ◽  
Methyl Ketones ◽  
Closed Vessel ◽  
Simple Metal ◽  
One Pot ◽  
X Ray ◽  
Metal Free

Two metal-free syntheses of 2,4,6-trisubstituted pyridines 10a–m and 16a–j are described. N,N,6-Trimethyl-4-(substituted)pyridin-2-amines 10 were prepared from aryl or heteroaryl methyl ketones which were transformed with N,N-dimethylacetamide dimethyl acetal (DMADMA) into enaminones 4a–m, followed by treatment with ammonium acetate to give (Z)-3-amino-1-(substituted)but-2-en-1-ones 5a–m. These were treated with DMADMA under microwave irradiation in a closed vessel at 130°C, to give via intermediates 7–9 the final products 10a–m. N2,N2,N4,N4-Tetramethyl-6-(substituted) pyridine-2,4-diamines 16a–j were prepared in a one-pot synthesis from the corresponding carboxamides 11a–j by treatment with an excess of DMADMA in a closed vessel under microwave irradiation to give via intermediates 12a–j to 15a–j the final products 16a–j. X-Ray single crystal diffractometry studies of the enaminones 5c, 5g, 5i, 5j, and 5m and 2,4,6-trisubstituted pyridines 16a, 16b, 16g, 16i, and 16j were consistent with the expected structures.

scholarly journals STABILITY-INDICATING METHOD FOR DETERMINATION OF TIZANIDINE HYDROCHLORIDE IN PHARMACEUTICAL LC-CAD METHOD USING CHEMOMETRIC APPROACH

2017 ◽  
Vol 1 (1) ◽  
pp. 61-66
Author(s):  
Mariana Brandalise ◽  
Pamela Cristina Lukasewicz Ferreira ◽  
Andrea Garcia Pereira ◽  
Leonardo Meneghini ◽  
Pedro Eduardo Fröehlich ◽  
...  
Keyword(s):  
Ammonium Acetate ◽  
Forced Degradation ◽  
Simple Method ◽  
Stability Indicating Method ◽  
Charged Aerosol ◽  
Charged Aerosol Detector ◽  
Chemometric Approach ◽  
Tablet Dosage ◽  
Drug Reference

A new LC method for tizanidine hydrochloride in tablet dosage form using a charged aerosol detector (CAD) is described. The influence of various parameters on chromatographic system was investigated by factorial designs and Derringer's desirability. Chromatographic conditions were: mobile phase constituted of acetonitrile and ammonium acetate buffer 17 mM (60:40; v/v), column oven at 39 °C and flow rate 0.8 mL.min-1 performed in on Acclaim Trinity P1 column UV at 230 nm. Thus, it was possible to validate a simple method to assay the tizanidine and its counter-ion in three formulations (drug reference, generic and manipulated). Method showed specificity when challenged by forced degradation and excipients. Finally, the method was compared with USP monograph method demonstrating equivalence in assay evaluation.

Killing two birds with one stone: simultaneous extraction of DNA and RNA from activated sludge biomass

1999 ◽  
Vol 45 (3) ◽  
pp. 269-272 ◽  
Author(s):  
Zhongtang Yu ◽  
William W Mohn
Keyword(s):  
Activated Sludge ◽  
Ammonium Acetate ◽  
Rna Extraction ◽  
Cell Lysis ◽  
Biomass Density ◽  
Simple Method ◽  
Dna And Rna ◽  
Acid Recovery ◽  
Bacterial Aggregate ◽  
Soil And Sediment

DNA and RNA are usually extracted from activated sludge samples using two separate methods developed for soil and sediment samples. However, activated sludge differs from soil and sediment in at least three aspects: high biomass density, low humic acid content, and the presence of bacterial aggregate flocs. Taking these characteristics into consideration, we developed a simple and rapid method allowing simultaneous DNA and RNA extraction from activated sludge samples. This method combines (i) mini-bead beating, which is most efficient in breaking bacterial aggregate flocs and cells, (ii) protection of RNA with diethyl pyrocarbonate, and (iii) precipitation of impurities with ammonium acetate. Phenol/chloroform extraction and column purification are not necessary. The resulting DNA and RNA are suitable for PCR and reverse transcriptase - PCR, respectively. The efficiencies of cell lysis and nucleic acid recovery were high enough to permit detection by PCR of 102cells/mL of mixed liquor. By simultaneously extracting both DNA and RNA from a single sample, this method eliminates variability in cell lysis between extraction of DNA and RNA using two different methods. This extraction method is rapid, and within 1 h, one person can process four or more samples. This simple method makes it easier to analyze a large number of activated sludge samples.Key words: activated sludge, DNA, extraction, PCR, RNA.

A simple synthesis of dimethyl 2-[(Z)-3-amino-1-oxo-1-(substituted)but-2-en-2-yl]fumarates: potential intermediates in the synthesis of polysubstituted five- and six-membered heterocycles

2016 ◽  
Vol 71 (6) ◽  
pp. 677-682 ◽  
Author(s):  
Rok Šinkovec ◽  
Uroš Grošelj ◽  
Benjamin Prek ◽  
Marta Počkaj ◽  
Sebastijan Ričko ◽  
...  
Keyword(s):  
Ammonium Acetate ◽  
Dimethyl Acetal ◽  
Simple Synthesis ◽  
Dimethyl Acetylenedicarboxylate ◽  
Methyl Ketones ◽  
Metal Free

AbstractIn this communication, a simple synthesis of dimethyl 2-[(Z)-3-amino-1-oxo-1-(substituted)but-2-en-2-yl]fumarates is described. Methyl ketones were transformed by treatment with N,N-dimethylacetamide dimethyl acetal (DMADMA) into 3-dimethylamino-1-(substituted)but-2-en-1-ones, followed by treatment with ammonium acetate into (Z)-3-amino-1-(substituted)but-2-en-1-ones and addition to dimethyl acetylenedicarboxylate. These novel polysubstituted butadienes are potential intermediates for the metal-free preparation of polysubstituted five- and six-membered heterocycles.

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.

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