Synthesis of Oxathiolone Fused Chalcones Bearing O-Aminoalkyl Side Chain. Comparison of Stability of Isomeric Benzoxathiolones under Alkylation Reaction Conditions

: Tuberculosis remains a highly infectious disease across the world. In the identification of new antitubercular agents, coumarin clubbed thiadiazole amides have been synthesized and evaluated for in vitro antitubercular activity. Due to the growing concern about chemicals and their impact on the environment, greener and faster reaction conditions needed to be incorporated. Therefore, we used TBTU as a coupling reagent for efficient and facile synthesis of substituted-N-(5-((7-methyl-2-oxo-2H-chromes-4-yl)-methyl)-1,3, 4 - thiadiazol-2-yl)-benzamide 4a-j with good yields up to 95% in mild reaction condition. All the synthesized compounds were evaluated in vitro for antitubercular activity against the H37Rv strain of M.Tuberculosis. Compounds 4c, 4f, and 4j were found active at 25 µg/mL against M. tb H37Rv. Electron withdrawing substituents present on aromatic side-chain showed promising anti-tubercular activity.

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An investigation of a Friedel-Crafts alkylation reaction in homogeneous supercritical CO2 and under subcritical and splitphase reaction conditions

Advances in Environmental Research ◽

10.1016/s1093-0191(00)00030-7 ◽

2000 ◽

Vol 4 (4) ◽

pp. 307-312 ◽

Cited By ~ 21

Author(s):

John E. Chateauneuf ◽

Kan Nie

Keyword(s):

Supercritical Co2 ◽

Alkylation Reaction ◽

Reaction Conditions

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DERA in Flow: Synthesis of a Statin Side Chain Precursor in Continuous Flow Employing Deoxyribose-5-Phosphate Aldolase Immobilized in Alginate-Luffa Matrix

Catalysts ◽

10.3390/catal10010137 ◽

2020 ◽

Vol 10 (1) ◽

pp. 137 ◽

Cited By ~ 2

Author(s):

Bianca Grabner ◽

Yekaterina Pokhilchuk ◽

Heidrun Gruber-Woelfler

Keyword(s):

Renewable Resources ◽

Continuous Flow ◽

Ph Value ◽

Continuous Process ◽

Side Chain ◽

Hydroxyl Groups ◽

Inexpensive Method ◽

Reaction Conditions ◽

Flow Process ◽

Artery Disease

Statins, cholesterol-lowering drugs used for the treatment of coronary artery disease (CAD), are among the top 10 prescribed drugs worldwide. However, the synthesis of their characteristic side chain containing two chiral hydroxyl groups can be challenging. The application of deoxyribose-5-phosphate aldolase (DERA) is currently one of the most promising routes for the synthesis of this side chain. Herein, we describe the development of a continuous flow process for the biosynthesis of a side chain precursor. Design of experiments (DoE) was used to optimize the reaction conditions (pH value and temperature) in batch. A pH of 7.5 and a temperature of 32.5 °C were identified to be the optimal process settings within the reaction space considered. Additionally, an immobilization method was developed using the alginate-luffa matrix (ALM), which is a fast, simple, and inexpensive method for enzyme immobilization. Furthermore, it is non-toxic, biodegradable, and from renewable resources. The final continuous process was operated stable for 4 h and can produce up to 4.5 g of product per day.

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Structure and Mechanism of Human UDP-glucose 6-Dehydrogenase

Journal of Biological Chemistry ◽

10.1074/jbc.m111.234682 ◽

2011 ◽

Vol 286 (27) ◽

pp. 23877-23887 ◽

Cited By ~ 39

Author(s):

Sigrid Egger ◽

Apirat Chaikuad ◽

Kathryn L. Kavanagh ◽

Udo Oppermann ◽

Bernd Nidetzky

Keyword(s):

Active Site ◽

Quaternary Structure ◽

Binding Domain ◽

Side Chain ◽

Reaction Conditions ◽

Epithelial Tumor ◽

Coenzyme Binding ◽

Ternary Complex Formation ◽

The Matrix

Elevated production of the matrix glycosaminoglycan hyaluronan is strongly implicated in epithelial tumor progression. Inhibition of synthesis of the hyaluronan precursor UDP-glucuronic acid (UDP-GlcUA) therefore presents an emerging target for cancer therapy. Human UDP-glucose 6-dehydrogenase (hUGDH) catalyzes, in two NAD+-dependent steps without release of intermediate aldehyde, the biosynthetic oxidation of UDP-glucose (UDP-Glc) to UDP-GlcUA. Here, we present a structural characterization of the hUGDH reaction coordinate using crystal structures of the apoenzyme and ternary complexes of the enzyme bound with UDP-Glc/NADH and UDP-GlcUA/NAD+. The quaternary structure of hUGDH is a disc-shaped trimer of homodimers whose subunits consist of two discrete α/β domains with the active site located in the interdomain cleft. Ternary complex formation is accompanied by rigid-body and restrained movement of the N-terminal NAD+ binding domain, sequestering substrate and coenzyme in their reactive positions through interdomain closure. By alternating between conformations in and out of the active site during domain motion, Tyr14, Glu161, and Glu165 participate in control of coenzyme binding and release during 2-fold oxidation. The proposed mechanism of hUGDH involves formation and breakdown of thiohemiacetal and thioester intermediates whereby Cys276 functions as the catalytic nucleophile. Stopped-flow kinetic data capture the essential deprotonation of Cys276 in the course of the first oxidation step, allowing the thiolate side chain to act as a trap of the incipient aldehyde. Because thiohemiacetal intermediate accumulates at steady state under physiological reaction conditions, hUGDH inhibition might best explore ligand binding to the NAD+ binding domain.

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Photo Alignment Behaviour of Polyethene Imine Having Cyano Azobenzene Side Chain

Dhaka University Journal of Science ◽

10.3329/dujs.v63i2.24434 ◽

2015 ◽

Vol 63 (2) ◽

pp. 67-72

Author(s):

Mohammad Kamruzzaman ◽

Seiji Kurihara

Keyword(s):

Molecular Orientation ◽

Uv Light ◽

Side Chain ◽

Reaction Parameters ◽

Reaction Conditions ◽

Out Of Plane ◽

Solid Film ◽

New Type ◽

Photo Alignment ◽

Random State

New type of polyethene imine having cyano (-CN) side chain through six methylene spacer group (PEI6C) was successfully synthesised and characterised. The effect of reaction parameters on degree of substitution of PEI6C was also studied and the reaction conditions were optimised. Photochemical as well as photoorientational behaviour of the polymer were investigated. PEI6C in solid film exhibited photoresponsive properties upon irradiation with UV and visible light. PEI6C film also exhibited reversible molecular orientation from random state to out-of-plane and from out-of-plane to random state upon non-polarised visible and UV light irradiation.Dhaka Univ. J. Sci. 63(2): 67-72, 2015 (July)

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A study on hybrid oligomeric type II photoinitiator

e-Polymers ◽

10.1515/epoly.2010.10.1.1533 ◽

2010 ◽

Vol 10 (1) ◽

Author(s):

Guodong Ye ◽

Wenbo Kan ◽

Jianwen Yang ◽

Zhaohua Zeng ◽

Xiaoxuan Liu

Keyword(s):

Side Chain ◽

Radical Scavenger ◽

Reaction Conditions ◽

Volatile Organic ◽

Reaction Proceeds ◽

Result Show ◽

Lower Ionization Potential ◽

And Migration ◽

Photo Curing ◽

Vocs Emission

AbstractPreparing tailor-made hybrid photoinitiator (PI) for specific applications continues to gain momentum. The hybrid PIs comprising both H-abstraction chromophore and coinitiator moiety are the candidate materials with energy-saving and environment-protection in the photo-curing field. So two oligomeric photoinitiators (OMKs) containing benzophenone (BP) and aliphatic tert-amines chromophore in the main-chain (OMK-2) or side-chain (OMK-1) were synthesized and characterized respectively. Photophysical investigation showed that the absorption maxima of OMKs were around 340 nm, red shifted about 5-10 nm compared to BP. Their initiation efficiencies were found to be higher than that of BP and 4,4’-bis(dimethylamino)benzophenone(MK) respectively. The reaction proceeds via a simple electron-transfer/proton-transfer mechanism. Dynamic NMR data reveal that H-abstraction reacts predominantly via alpha H of aliphatic tertamines, as might be expected on the basis of the lower ionization potential and bond dissociation energy of aliphatic amines compared to aromatic amines. The reaction mechanism of H-abstraction was confirmed by using radical scavenger 2,2,6,6-tetramethylpiperidin-1-oxy(TEMPO), which acts as a probe under photolysis reaction conditions. The volatility and migration were tested under simulated conditions, the result show that OMKs exhibited very low volatility and significantly reduced migration compared to the low molecular analogs. Results showed that the OMKs are the promising candidate as higher efficient PIs with low volatile organic compounds (VOCs) emission and reduced migration. They are suitable for environmental-friendly formulations.

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Simple and Rapid Spectrophotometry Method for Determination of Adrenaline and Isoprenaline

Journal of AOAC INTERNATIONAL ◽

10.1093/jaoac/71.4.764 ◽

1988 ◽

Vol 71 (4) ◽

pp. 764-767

Author(s):

Salwa R El-Shabouri ◽

Samiha A Hussein ◽

Abdel-Alim M Abdel-Alim

Keyword(s):

Aqueous Solution ◽

Sodium Chloride ◽

Oxidation Reaction ◽

Silver Oxide ◽

Oxidative Degradation ◽

Side Chain ◽

Sodium Metabisulfite ◽

Specific Method ◽

Reaction Conditions

Abstract A simple, rapid, and specific method for determination of adrenaline bitartrate and isoprenaline sulfate was developed. The method is based on the oxidation reaction in aqueous solution of either adrenaline bitartrate or isoprenaline sulfate in the presence of silver oxide to give a red aminochrome measurable at 490 nm. The color is stable for 2 h. Beer's law is valid within a concentration range of 5-80 ng/ mL for each drug. All variables were studied to optimize the reaction conditions. The method is specific for catecholamine drugs having a secondary amine in the side chain. Other catecholamines such as orciprenaline and noradrenaline do not interfere, and no interference was observed in the presence of common pharmaceutical adjuvants. Interference due to sodium metabisulfite and sodium chloride was circumvented. The validity of the method was tested by analyzing adrenaline injections and isoprenaline tablets. Good recoveries were obtained for these preparations. The results were comparable to those obtained by official procedures. The proposed method is also recommended as a stability indicating assay for oxidative degradation of both drugs.

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Functional Polysilanes and their Optical, Chiroptical and Photoluminescence Properties

Current Organocatalysis ◽

10.2174/2213337206666190415124549 ◽

2019 ◽

Vol 6 (3) ◽

pp. 193-221 ◽

Cited By ~ 1

Author(s):

Km. Meenu ◽

Dibyendu S. Bag ◽

Rekha Lagarkha ◽

Radha Tomar ◽

Arvind K. Gupta

Keyword(s):

Functional Group ◽

Photophysical Properties ◽

Coupling Reaction ◽

Functional Materials ◽

Side Chain ◽

Inorganic Polymers ◽

Reaction Conditions ◽

Wurtz Coupling ◽

Single Material ◽

Boiling Toluene

‘Polysilanes’ is an important class of inorganic polymers having Si-Si σ-conjugation along the backbone. They exhibit extraordinary electronic and photophysical properties and find suitable optoelectronics applications. They are typically synthesized by Wurtz coupling reaction of dichlorodialkylsilane or dichlorodiphenylsilane or dichloroalkylphenylsilane and their combinations under drastic reaction conditions by using sodium dispersion in boiling toluene. In such a drastic condition, no functional groups sustain with polysilane polymer. In order to achieve such functional materials, researchers have been interested in synthesizing functional polysilane with a different functional group like a chiral group, azobenzene containing chromophore and other heteroatoms in their main chain or side chain. Therefore, it is a very challenging task to synthesize polysilanes having effective functionality integrated with their structures. However, the modern technological demand of materials leads to efforts to obtain polymers having functional and multifunctional activity in a single material. In this review article, we cover the synthesis of polysilane with functional activity via pre-polymerization and post-polymerization with a functional group.

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Catalytic Alkylation of Brown Coal and Peat

Eurasian Chemico-Technological Journal ◽

10.18321/ectj99 ◽

2011 ◽

Vol 14 (1) ◽

pp. 45

Author(s):

S.I. Zherebtsov ◽

Z.R. Ismagilov

Keyword(s):

Fatty Acids ◽

Organic Acids ◽

Brown Coal ◽

Alkylation Reaction ◽

Low Grade ◽

Regression Equations ◽

Alkyl Esters ◽

Reaction Conditions ◽

The Impact ◽

Positive Effect

The alcohol alkylation of low-grade metamorphic coal and peat in the presence of mineral and organic acids was studied using FTIR, NMR, and GC-MS. The impact of the reaction conditions on the yield of extractable matter was investigated experimentally, and relevant regression equations were obtained. Changes in the group and individual compositions of the wax fractions of bitumen in the process of brown coal and peat alkylation were studied. It was found that the esters of alkylated coal waxes consisted of native esters of fatty acids, and alkyl esters of these acids formed as a result of the alkylation reaction. Esterification and transesterification were predominant in the reactions of the bitumen fraction components. The positive effect of alcohol alkylation on the increase of the bitumen yield was found.

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