scholarly journals Highly Asymmetric Reduction of New Benzofuryl and Benzothiophenyl α-Amino Ketones

Proceedings ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 49
Author(s):  
Agnieszka Tafelska-Kaczmarek ◽  
Marcin Kwit ◽  
Bartosz Stasiak
Keyword(s):  
High Performance ◽  
Asymmetric Reduction ◽  
Theoretical Calculations ◽  
Transfer Hydrogenation ◽  
Central Position ◽  
Chiral Hplc ◽  
Naturally Occurring ◽  
Approved Drugs ◽  
High Yields ◽  
Derivatives Of

Heterocyclic compounds play an important role in medicinal chemistry and occupy a central position in synthetic organic chemistry. Both benzofuran and benzothiophene are considered as very important structures due to their diverse biological and pharmacological profile. Many clinically approved drugs are synthetic and naturally occurring substituted benzofuryl and benzothiophenyl derivatives in conjunction with other heterocycles. Therefore, a new series of α-amino ketone (containing various azole rings) derivatives of benzofuran and benzothiophene are synthesized and subjected to the transfer hydrogenation with formic acid, catalyzed by RhCl[(R,R)-TsDPEN](C5Me5). The corresponding optically active β-amino alcohols are obtained in high yields and excellent enantioselectivities (93%–99%), as determined by chiral HPLC (high-performance liquid chromatography). The absolute configuration of the products is confirmed by means of ECD (electronic circular dichroism) spectroscopy, supported by theoretical calculations.

Methods for Detection and Quantitation of Fumonisins in Corn, Cereal Products and Animal Excreta

1994 ◽  
Vol 57 (6) ◽  
pp. 536-540 ◽  
Author(s):  
LARRY G. RICE ◽  
P. FRANK ROSS
Keyword(s):  
High Performance ◽  
Parent Compound ◽  
Fumonisin B1 ◽  
Epidemiological Evidence ◽  
Cereal Products ◽  
Naturally Occurring ◽  
Animal Excreta ◽  
Fumonisin B2 ◽  
Human Esophageal Cancer ◽  
Derivatives Of

Fumonisins are a group of naturally occurring mycotoxins produced by strains of several different mating populations of Gibberella fujikori (Fusarium section Liseola). Fumonisins have been shown experimentally to be the causative agent of equine leukoencephalomalacia (ELEM), porcine pulmonary edema (PPE) syndrome, and to produce liver cancer in rats. Epidemiological evidence also indicates a possible correlation between the fumonisins and human esophageal cancer. The analytical method of choice for most samples has been high performance liquid chromatography (HPLC) using fluorescence detection. The present work describes the baseline resolution using an isocratic mobile phase of the o-phthalaldehyde (OPA) derivatives of fumonisin B1 (FB1), fumonisin B2 (FB2) and fumonisin B3 (FB3). The separation of the hydrolyzed forms of FB1, partially hydrolyzed FB1 (PHFB1) and fully hydrolyzed FB1 (HFB1) is also described. Results of analyses of com from 1992 crop year in both Iowa (mean = 0.05 μg/g, N = 80) and Pennsylvania (mean = 0.37 μg/g, N = 91) were significantly lower than mean levels reported for 1988, 1989, 1990 and 1991. Significant levels of FB1 were found in commercially prepared rat (2 μg/g) and horse (37 μg/g) feed. Levels of FB1, (0.05 to 1.2 μg/g) found in corn meal purchased from local groceries indicated a possible source of low level exposure of humans to fumonisins. The simultaneous isocratic separation of FB1, FB2, FB3 and the hydrolysis products of FB1, PHFB1 and HFB1from fecal samples indicated a possible difference in metabolism of FB1 in ruminants and nonruminants. In ruminants, the hydrolyzed forms of FB1 composed a significant (60 to 90%) portion of the total FB1 concentration found in the feces. In nonruminants, the parent compound, FB1, was the dominant (90%) species present. Both ruminants and nonruminants showed limited excretion of FB1 in their urine (<1 to 7% total FB1 in excreta).

Asymmetric Reduction of Trifluoromethyl Alkynyl Ketimines by Chiral Phosphoric Acid and Benzothiazoline

Synlett ◽  
2018 ◽  
Vol 29 (12) ◽  
pp. 1607-1610 ◽  
Author(s):  
Takahiko Akiyama ◽  
Masamichi Miyagawa ◽  
Kensuke Takashima
Keyword(s):  
Phosphoric Acid ◽  
Asymmetric Reduction ◽  
Hydrogenation Reaction ◽  
Transfer Hydrogenation ◽  
Trifluoromethyl Group ◽  
Combined Use ◽  
Chiral Phosphoric Acid ◽  
High Yields ◽  
Transfer Hydrogenation Reaction

An enantioselective transfer hydrogenation reaction of alkynyl ketimine bearing a trifluoromethyl group was accomplished. Chemoselective reduction of ketimine was achieved by the combined use of chiral phosphoric acid and benzothiazoline to give α-trifluoromethyl propargylamine in good to high yields and with excellent enantioselectivity.

Synthesis of 3-(Cyclohexylamino)-2-arylimidazo[1,2-a]pyridine-8- carboxylic Acids Via an Efficient Three-component Condensation Reaction between Cyclohexylisocyanide and 2-Aminopyridine-3-carboxylic Acid in the Presence of Aromatic Aldehyde

2018 ◽  
Vol 21 (4) ◽  
pp. 298-301 ◽  
Author(s):  
Ghasem Marandi
Keyword(s):  
Biological Sciences ◽  
Carboxylic Acid ◽  
Carboxylic Acids ◽  
High Performance ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
New Materials ◽  
One Pot ◽  
High Yields ◽  
Benzaldehyde Derivatives

Aim and Objective: The reaction of cyclohexylisocyanide and 2-aminopyridine-3- carboxylic acid in the presence of benzaldehyde derivatives in ethanol led to 3-(cyclohexylamino)-2- arylimidazo[1,2-a]pyridine-8-carboxylic acids in high yields. In a three component condensation reaction, isocyanide reacts with 2-aminopyridine-3-carboxylic acid and aromatic aldehydes without any prior activation. Material and Methods: The synthesized products have stable structures which have been characterized by IR, 1H, 13C and Mass spectroscopy as well as CHN-O analysis. Results: In continuation of our attempts to develop simple one-pot routes for the synthesis of 3- (cyclohexylamino)-2-arylimidazo[1,2-a]pyridine-8-carboxylic acids, aromatic aldehydes with divers substituted show a high performance. Conclusion: In conclusion, this study introduces the art of combinatorial chemistry using a simple one-pot procedure for the synthesis of new materials which are interesting compounds in medicinal and biological sciences.

Directed biosynthesis of novel derivatives of echinomycin. II. Purification and structure elucidation

1984 ◽  
Vol 30 (6) ◽  
pp. 730-738 ◽  
Author(s):  
D. Gauvreau ◽  
M. J. Waring
Keyword(s):  
High Performance ◽  
Reversed Phase ◽  
Aromatic Acids ◽  
Antibacterial Assay ◽  
New Antibiotics ◽  
Field Desorption Mass Spectrometry ◽  
Directed Biosynthesis ◽  
Phase Systems ◽  
Derivatives Of ◽  
Acid Precursor

New antibiotics produced by Streptomyces echinatus A8331 cultured in the presence of heterocyclic aromatic acids can be separated and purified by high-performance liquid chromatography using reversed phase columns. Natural quinoxaline antibiotics and certain quinoline derivatives can also be efficiently separated in normal phase systems. Details of purification procedures are described together with experiments to characterise the new antibiotics by field desorption mass spectrometry and proton magnetic resonance. Mono- and bis-substituted derivatives of echinomycin containing the following replacement chromophores have been isolated: 7-chloroquinoxaline-2-carbonyl, thieno[3,2-b]pyridine-5-carbonyl, and 6-methylquinoline-2-carbonyl. With a 6-methylquinoline-2-carboxylic acid precursor the analogues containing one or two replacement chromophores are each separable into two distinct components. One of the bis-substituted 6-methylquinoline products appears inactive in an antibacterial assay and behaves as a triostin analogue, presumably an immediate precursor of the corresponding echinomycin derivative.

Ruthenium-catalyzed asymmetric reduction of 1,3-diketones using transfer hydrogenation

2001 ◽  
Vol 42 (30) ◽  
pp. 5005-5007 ◽  
Author(s):  
Janine Cossy ◽  
Florence Eustache ◽  
Peter I Dalko
Keyword(s):  
Asymmetric Reduction ◽  
Transfer Hydrogenation

scholarly journals Synergistic interaction of renewable nipagin and eugenol for high performance aromatic copoly(ether ester) materials

2021 ◽  
Author(s):  
Keling Hu ◽  
Huachao Sui ◽  
Dongping Zhao
Keyword(s):  
High Performance ◽  
Synergistic Interaction ◽  
Differential Scanning Calorimetric ◽  
Gravimetric Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molecular Weights ◽  
Chemical Structures ◽  
Naturally Occurring ◽  
Ether Ester

Abstract Naturally occurring nipagin and eugenol were used as the collaborative starting materials for poly(ether ester) materials. In this study, two series of nipagin and eugenol-derived copoly(ether ester)s, PHN11-xE1x and PHN11-xE2x (x = 0%, 5%, 10%, 15%, 20%), were prepared with renewable 1,6-hexanediol as a comonomer. The nipagin-derived component acts as the renewable surrogate of petroleum-based dimethyl terephthalate (DMT), while the eugenol-derived component acts as the cooperative property modifier of parent homopoly(ether ester) PHN1. 1,6-Hexanediol was chosen as the spacer because of its renewability and short chain to enhance the glass transition temperatures (Tgs) of materials. The molecular weights and chemical structures were confirmed by gel permeation chromatograph (GPC), NMR and FTIR spectroscopies. Thermal and crystalline properties were studied by thermal gravimetric analysis (TGA), differential scanning calorimetric (DSC) and wide-angle X-ray diffraction (WXRD). The tensile assays were conducted to evaluate the mechanical properties. The results suggest that properties of such kind of poly(ether ester)s can be finely tuned by the relative content of two components. Synergistic interaction of two structurally distinctive parts endows the materials with high performance.

scholarly journals Synthesis and anticonvulsant activity of 6-methyl-2-((2-oxo-2-arylethyl)thio)pyrimidin-4(3 H)-one derivatives and products of their cyclization

Pharmacia ◽  
2019 ◽  
Vol 66 (3) ◽  
pp. 141-146
Author(s):  
Hanna Severina ◽  
Olga O. Skupa ◽  
Natalya I. Voloshchuk ◽  
Marharyta M. Suleiman ◽  
Victoriya A. Georgiyants
Keyword(s):  
Sulphuric Acid ◽  
Anticonvulsant Activity ◽  
Sodium Methoxide ◽  
Structure Activity ◽  
Phenacyl Bromides ◽  
Pharmacological Screening ◽  
High Yields ◽  
Derivatives Of

The alkylation of 6-methyl-2-thioxo-2,3-dihydro-1H-pyrimidine-4-one phenacyl bromides under different conditions was investigated. It was found that during the reaction in the medium of DMF/K2CO3 a mixture of 2-(2-aryl-2-oxoethyl)thio-6-methyl-pyrimidine-4(3H)-one and 3-hydroxy-3-aryl-7-methyl-2,3-dihydro-5H-thiazolo[3,2-a]pyrimidine-5-one was formed. The holding of the resulting mixture in the concentrated sulphuric acid leads to the formation of cyclization products - derivatives of 3-aryl-7-methyl-5H-thiazolo[3,2-a]pyrimidin-5-one with high yields. Individual S-alkylated derivatives – 2-(2-aryl-2-oxoethyl)thio-6-methyl-pyrimidine-4(3H)-one - were obtained by reacting in methanol in the presence of sodium methoxide. Pharmacological screening of synthesized compounds for anticonvulsant activity on the model of pentylenetetrazole seizures in rats was carried out and some regularity “structure-activity” was established.

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