A photocatalytic radical relay reaction of 2-methylthiolated phenylalkynones and potassium metabisulfite

Reversing Reactivity: Stereoselective Desulfurative β-O-Glycosylation of Anomeric Thiosugars with Carboxylic Acids Under Copper or Cobalt Catalysis

10.26434/chemrxiv.11421576.v1 ◽

2019 ◽

Author(s):

Samir Messaoudi ◽

Nedjwa Bennai ◽

Amelie Chabrier ◽

Maha Fatthalla ◽

Expédite Yen-Pon ◽

...

Keyword(s):

Carboxylic Acids ◽

Late Stage ◽

Catalytic Amount ◽

Broad Scope ◽

Wide Range ◽

Glycosylation Reaction

We have discovered a new mode of reactivity of 1-thiosugars in the presence of Cu(II) or Co(II) for a stereoselective <i>O</i>-glycosylation reaction. The process involves the use of a catalytic amount of Cu(acac)2 or Co(acac)2 and Ag2CO3 as an oxidant in α,α,α-trifluorotoluene (TFT). Moreover, this protocol turned out to have a broad scope, allowing to prepare a wide range of com-plex substituted <i>O</i>-glycoside esters in good to excellent yields with an exclusive β-selectivity. The late-stage modification of phar-maceuticals by this method was also demonstrated.

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Photocatalytic Alkylation of Pyrroles and Indoles with α-Diazo Esters

10.26434/chemrxiv.8230235 ◽

2019 ◽

Author(s):

Łukasz Ciszewski ◽

Jakub Durka ◽

Dorota Gryko

Keyword(s):

Aromatic Compounds ◽

Reaction Pathway ◽

Alkylating Agents ◽

Catalytic Amount ◽

Radical Formation ◽

Reaction Selectivity ◽

Diazo Esters ◽

Electron Withdrawing Substituents

This article describes direct photoalkylation of electron-rich aromatic compounds with diazo compoiunds. C-2 alkylated indoles and pyrroles are obtained with good yields even though the photocatalyst (Ru(bpy)3Cl2) loading is as low as 0.075 mol %. For substrates bearing electron-withdrawing substituents the addition of a catalytic amount of N,N-dimethyl-4-methoxyaniline is required. Both EWG-EWG and EWG-EDG substituted diazo esters are suitable as alkylating agents. The reaction selectivity and mechanistic experiments suggest that carbenes/carbenoid intermediates are not involved in the reaction pathway, instead radical formation is proposed.

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Microwave assisted synthesis of novel Pyrazole derivatives and their biological evaluation as anti-bacterial agents

Combinatorial Chemistry & High Throughput Screening ◽

10.2174/1386207323666201019152206 ◽

2020 ◽

Vol 23 ◽

Author(s):

Hadis Khodadad ◽

Farhad Hatamjafari ◽

Khalil Pourshamsian ◽

Babak Sadeghi

Keyword(s):

Antibacterial Activity ◽

Aromatic Aldehydes ◽

Catalytic Amount ◽

Antibacterial Activities ◽

Structural Features ◽

Biological Evaluation ◽

Aureus Strain ◽

Microwave Assisted Synthesis ◽

Pyrazole Derivatives ◽

Microwave Assisted

Aim and Objective: Microwave-assisted condensation of acetophenone 1 and aromatic aldehydes 2 gave chalcone analogs 3, which were cyclized to pyrazole derivatives 6a-f via the reaction with hydrazine hydrate and oxalic acid in the presence of the catalytic amount of acetic acid in ethanol. Materials and Methods: The structural features of the synthesized compounds were characterized by melting point, FT-IR, 1H, 13C NMR and elemental analysis. Results: The antibacterial activities of the synthesized pyrazoles was evaluated against three gram-positive bacteria such as Enterococcus durans, Staphylococcus aureus, Bacillus subtilis and two gram-negative bacteria such as Escherichia coli and Salmonella typhimurium. Conclusion: All the synthesized pyrazoles showed relatively high antibacterial activity against S. aureus strain and none of them demonstrated antibacterial activity against E. coli.

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Zinc Sulfamate Catalyzed Efficient Selective Synthesis of Benzimidazole Derivatives under Ambient Conditions

Letters in Organic Chemistry ◽

10.2174/1570178616666181211094040 ◽

2019 ◽

Vol 16 (9) ◽

pp. 740-749

Author(s):

Sushil R. Mathapati ◽

Arvind H. Jadhav ◽

Mantosh B. Swami ◽

Jairaj K. Dawle

Keyword(s):

Benzimidazole Derivative ◽

Sulfamic Acid ◽

Aromatic Aldehydes ◽

Catalytic Amount ◽

Product Yield ◽

Lewis Acidity ◽

Benzimidazole Derivatives ◽

Ambient Conditions ◽

Reaction Condition ◽

Green Approach

Zinc sulfamate (Zn(NH2SO3)2 is a derivative of sulfamic acid (H3NSO3) which possesses “Lewis acidity” and finds well suited in a number of catalytic applications. The present paper describes an efficient, eco-friendly, and clean synthesis of 2-substituted benzimidazole derivatives by reacting diverse o-phenylenediamine with various substituted aromatic aldehydes using a catalytic amount of zinc sulfamate in ethanol at ambient temperature. As a result, 10 mol.% of Zinc sulfamate catalyst showed 92% of respective product yield with 100% conversion using short reaction period in ethanol. Meanwhile, effect of reaction parameters, such as amount of catalyst, different solvents, and reaction temperature on reaction product, was also studied. In addition, in the optimized reaction condition various substituted biological important benzimidazoles derivatives were prepared by using optimized reaction condition in good to efficient yield. In addition, possible reaction mechanism in the presence of zinc sulfamate for the preparation of benzimidazole derivative was sketched and discussed. The present green approach showed significances with faster reaction rate with inexpensive catalyst, which showed excellent and clean yield of benzimidazole in mild reaction condition with easy work-up procedure.

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Structure-Based Designing, Solvent Less Synthesis of 1,2,3,4-Tetrahydropyrimidine-5-carboxylate Derivatives: A Combined In Vitro and In Silico Screening Approach

Molecules ◽

10.3390/molecules26154424 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4424

Author(s):

Uzma Arshad ◽

Sibtain Ahmed ◽

Nusrat Shafiq ◽

Zaheer Ahmad ◽

Aqsa Hassan ◽

...

Keyword(s):

Virtual Screening ◽

Catalytic Amount ◽

Pyrimidine Derivatives ◽

Qsar Studies ◽

Lead Compounds ◽

Biological Potential ◽

Anti Cancer ◽

Anti Oxidant ◽

Vitro Analysis

Objective: In this study, small molecules possessing tetrahydropyrimidine derivatives have been synthesized having halogenated benzyl derivatives and carboxylate linkage. As previously reported, FDA approved halogenated pyrimidine derivatives prompted us to synthesize novel compounds in order to evaluate their biological potential. Methodology: Eight pyrimidine derivatives have been synthesized from ethyl acetoacetate, secondary amine, aromatic benzaldehyde by adding catalytic amount of CuCl2·2H2O via solvent less Grindstone multicomponent reagent method. Molecular structure reactivity and virtual screening were performed to check their biological efficacy as an anti-oxidant, anti-cancer and anti-diabetic agent. These studies were supported by in vitro analysis and QSAR studies. Results: After combined experimental and virtual screening 5c, 5g and 5e could serve as lead compounds, having low IC50 and high binding affinity.

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Lipase Catalyzed Synthesis of Enantiopure Precursors and Derivatives for β-Blockers Practolol, Pindolol and Carteolol

Catalysts ◽

10.3390/catal11040503 ◽

2021 ◽

Vol 11 (4) ◽

pp. 503

Author(s):

Morten Gundersen ◽

Guro Austli ◽

Sigrid Løvland ◽

Mari Hansen ◽

Mari Rødseth ◽

...

Keyword(s):

Building Block ◽

Kinetic Resolution ◽

Enantiomeric Excess ◽

Catalytic Amount ◽

Building Blocks ◽

Β Blocker ◽

Β Blockers ◽

Optical Rotations ◽

Reported Data ◽

By Products

Sustainable methods for producing enantiopure drugs have been developed. Chlorohydrins as building blocks for several β-blockers have been synthesized in high enantiomeric purity by chemo-enzymatic methods. The yield of the chlorohydrins increased by the use of catalytic amount of base. The reason for this was found to be the reduced formation of the dimeric by-products compared to the use of higher concentration of the base. An overall reduction of reagents and reaction time was also obtained compared to our previously reported data of similar compounds. The enantiomers of the chlorohydrin building blocks were obtained by kinetic resolution of the racemate in transesterification reactions catalyzed by Candida antarctica Lipase B (CALB). Optical rotations confirmed the absolute configuration of the enantiopure drugs. The β-blocker (S)-practolol ((S)-N-(4-(2-hydroxy-3-(isopropylamino)propoxy)phenyl)acetamide) was synthesized with 96% enantiomeric excess (ee) from the chlorohydrin (R)-N-(4-(3-chloro-2 hydroxypropoxy)phenyl)acetamide, which was produced in 97% ee and with 27% yield. Racemic building block 1-((1H-indol-4-yl)oxy)-3-chloropropan-2-ol for the β-blocker pindolol was produced in 53% yield and (R)-1-((1H-indol-4-yl)oxy)-3-chloropropan-2-ol was produced in 92% ee. The chlorohydrin 7-(3-chloro-2-hydroxypropoxy)-3,4-dihydroquinolin-2(1H)-one, a building block for a derivative of carteolol was produced in 77% yield. (R)-7-(3-Chloro-2-hydroxypropoxy)-3,4-dihydroquinolin-2(1H)-one was obtained in 96% ee. The S-enantiomer of this carteolol derivative was produced in 97% ee in 87% yield. Racemic building block 5-(3-chloro-2-hydroxypropoxy)-3,4-dihydroquinolin-2(1H)-one, building block for the drug carteolol, was also produced in 53% yield, with 96% ee of the R-chlorohydrin (R)-5-(3-chloro-2-hydroxypropoxy)-3,4-dihydroquinolin-2(1H)-one. (S)-Carteolol was produced in 96% ee with low yield, which easily can be improved.

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Nickel-catalyzed oxidative C–H/N–H annulation of N-heteroaromatic compounds with alkynes

Chemical Science ◽

10.1039/c8sc05063e ◽

2019 ◽

Vol 10 (11) ◽

pp. 3242-3248 ◽

Cited By ~ 20

Author(s):

Atsushi Obata ◽

Akane Sasagawa ◽

Ken Yamazaki ◽

Yusuke Ano ◽

Naoto Chatani

Keyword(s):

Nickel Complex ◽

Catalytic Amount ◽

Pyrazole Derivatives ◽

Heteroaromatic Compounds

The reaction of N-heteroaromatic compounds, such as 2-aryl-pyrrole, benzimidazole, imidazole, indole, and pyrazole derivatives, with alkynes in the presence of a catalytic amount of a nickel complex results in C–H/N–H oxidative annulation.

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