1) The document describes the synthesis and application of heterogeneous zinc catalysts for decarboxylative coupling reactions. Chitosan-supported zinc nitrate and zinc chloride catalysts were prepared and characterized.
2) Screening experiments evaluated the catalytic activity of the catalysts in synthesizing propargylamine through the decarboxylative coupling of phenylglyoxylic acid, morpholine, and phenylacetylene. Chitosan-supported zinc nitrate showed better reactivity and was further optimized.
3) Under optimized conditions using chitosan-supported zinc nitrate under solvent-free conditions, the three-component coupling successfully produced propargylamine in good yield through a decar
Light-Induced Controlled Free Radical Polymerization of Methacrylates Using I...Pawan Kumar
A novel visible light mediated catalytic system
based on low cost iron complex, that is, Fe(bpy)3(PF)6 photocatalyst
that initiates and control the free radical polymerization
of methacrylates using ethyl a-bromoisobutyrate (EBriB) as an
initiator and 20 watt LED as light source is developed. The
polymerization is initiated with turning the light on and immediately
terminated by turning the light off. In addition, the
molecular weight of polymer can be varied by changing the
ratio of monomer and initiator. The merits of the present methodology
lie in the use of low cost less precious, highly abundant
iron-based photocatalyst, avoidance of sacrificial donor
and need of lower catalyst amount under visible light. The
optimum amount of catalyst and initiator were established and
successful polymerization of various methacrylates was
achieved under the optimized polymerization conditions.
Electrochemical Stability of Stainless Steels-Made Alkaline Water Electrolysi...Tohoku University
Developing highly active and durable electrocatalysts for oxygen evolution reaction (OER) have been needed for efficient hydrogen production by alkaline water electrolysis (AWE). Austenitic stainless steels (SS) have attracted attentions as the alternative anode materials to Ni-based electrodes (1, 2). We recently demonstrated that NiFe hydroxide/oxide hetero nanostructures that synthesized through the constant current density electrolysis of 316SS (NiFe-HyOx/SS) show high OER activity and stability under constant current operation conditions (3). However, the electrochemical stability and OER overpotentials of the surface catalyst layers generated on the stainless steel under potential fluctuation is still not clear. In this study, we investigated changes in OER overpotentials of the NiFe-HyOx/SS anode during applying potential cycles (PCs) of 0.5 and 1.8 V vs. reversible hydrogen electrode (RHE) and discussed the structural changes.
Effect of ordering of PtCu3 electrocatalyst structure on the stability for ox...Nejc Hodnik
Presentation at the 10th European Symposium on Electrochemical Engineering, Sardinia, Italy
September 28, 2014 to October 02, 2014
Authors:
Nejc Hodnik1,2, C. Jeyabharathi1,3, K. Phani3, A. Rečnik4, M. Bele2, S. Hočevar2, M. Gaberšček2 and K. Mayrhofer1
1Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany
Department of Interface Chemistry and Surface Engineering
Electrocatalysis Group
2National Institute of Chemistry, Ljubljana, Slovenia
3CSIR-Central Electrochemical Research Institute, Tamil Nadu, India
4Jožef Stefan Institute, Ljubljana, Slovenia
The homolytic cleavage of covalent bonds in carbonyl compound under photochemical conditions known as Norrish Type Reactions
They are divided into two types
Norrish Type I
Norrish Type II reaction
Light-Induced Controlled Free Radical Polymerization of Methacrylates Using I...Pawan Kumar
A novel visible light mediated catalytic system
based on low cost iron complex, that is, Fe(bpy)3(PF)6 photocatalyst
that initiates and control the free radical polymerization
of methacrylates using ethyl a-bromoisobutyrate (EBriB) as an
initiator and 20 watt LED as light source is developed. The
polymerization is initiated with turning the light on and immediately
terminated by turning the light off. In addition, the
molecular weight of polymer can be varied by changing the
ratio of monomer and initiator. The merits of the present methodology
lie in the use of low cost less precious, highly abundant
iron-based photocatalyst, avoidance of sacrificial donor
and need of lower catalyst amount under visible light. The
optimum amount of catalyst and initiator were established and
successful polymerization of various methacrylates was
achieved under the optimized polymerization conditions.
Electrochemical Stability of Stainless Steels-Made Alkaline Water Electrolysi...Tohoku University
Developing highly active and durable electrocatalysts for oxygen evolution reaction (OER) have been needed for efficient hydrogen production by alkaline water electrolysis (AWE). Austenitic stainless steels (SS) have attracted attentions as the alternative anode materials to Ni-based electrodes (1, 2). We recently demonstrated that NiFe hydroxide/oxide hetero nanostructures that synthesized through the constant current density electrolysis of 316SS (NiFe-HyOx/SS) show high OER activity and stability under constant current operation conditions (3). However, the electrochemical stability and OER overpotentials of the surface catalyst layers generated on the stainless steel under potential fluctuation is still not clear. In this study, we investigated changes in OER overpotentials of the NiFe-HyOx/SS anode during applying potential cycles (PCs) of 0.5 and 1.8 V vs. reversible hydrogen electrode (RHE) and discussed the structural changes.
Effect of ordering of PtCu3 electrocatalyst structure on the stability for ox...Nejc Hodnik
Presentation at the 10th European Symposium on Electrochemical Engineering, Sardinia, Italy
September 28, 2014 to October 02, 2014
Authors:
Nejc Hodnik1,2, C. Jeyabharathi1,3, K. Phani3, A. Rečnik4, M. Bele2, S. Hočevar2, M. Gaberšček2 and K. Mayrhofer1
1Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany
Department of Interface Chemistry and Surface Engineering
Electrocatalysis Group
2National Institute of Chemistry, Ljubljana, Slovenia
3CSIR-Central Electrochemical Research Institute, Tamil Nadu, India
4Jožef Stefan Institute, Ljubljana, Slovenia
The homolytic cleavage of covalent bonds in carbonyl compound under photochemical conditions known as Norrish Type Reactions
They are divided into two types
Norrish Type I
Norrish Type II reaction
TRANSITION METAL CATALYSIS , THE DIFFERENT METALS OF TRANSITION USED AS CATALYTIC REAGENT WITH ITS PROPERTIES , THEIR CHARGE TRANSFER ITS REACTION INCLUDING COPPER, PALLADIUM FOLLWED BY HECKMAN, ULLMAN COUPLING REACTION, GILLMAN REACTION, HECK REACTION
The main objective of my PhD research at CEA Grenoble (M. Mazzanti, R. Demadrille) was related to a better understanding of the structure-property relationship in emissive lanthanide complexes with potential applications in opto-electronic devices. This was achieved by a careful design of lanthanide antennas based on either organic chromophores or transition metals as ligands, followed by a study of the structural and photophysical properties of the resulting complexes, in order to estimate and further predict the sensitization efficiencies.
In a first line of research, we have described and patented the incorporation of tetrazole groups as carboxylic acid replacements for the sensitization of lanthanide emission. We were able to show how the variation of ligand substituents influences the photophysical properties, allowing us to draw predictions and to adapt the structures for improving the emission efficiency. Some of the compounds have been successfully tested in OLED devices.
We also became interested in designing and studying new types of polymetallic architectures based on iridium complexes for the sensitization of lanthanide emission, as well as preliminary investigating the grafting of lanthanide complexes on silicon surfaces.
Discussion on photolysis, Norrish rearrangement, photolysis of azo compounds, isomerization and rearrangement, Fries rearrangement, chemiluminescence and bioluminescence
Modification & Application of Borate Zirconia CatalystRanjeet Kumar
Solid catalysts are of great advantages in alkylation reaction due to heterogenous reaction which makes separation of catalysts very easy and environment friendly. Here, sulfated and borate zirconia catalysts are used to search for ortho-xylene with Toluene & methanol. To find a new path to get o-xylene, catalysts surface was studied and a new mesoporous borate zirconia catalyst was prepared. Mesoporous Borate Zirconia had showed a very efficient path to manufature o-xylene.
TRANSITION METAL CATALYSIS , THE DIFFERENT METALS OF TRANSITION USED AS CATALYTIC REAGENT WITH ITS PROPERTIES , THEIR CHARGE TRANSFER ITS REACTION INCLUDING COPPER, PALLADIUM FOLLWED BY HECKMAN, ULLMAN COUPLING REACTION, GILLMAN REACTION, HECK REACTION
The main objective of my PhD research at CEA Grenoble (M. Mazzanti, R. Demadrille) was related to a better understanding of the structure-property relationship in emissive lanthanide complexes with potential applications in opto-electronic devices. This was achieved by a careful design of lanthanide antennas based on either organic chromophores or transition metals as ligands, followed by a study of the structural and photophysical properties of the resulting complexes, in order to estimate and further predict the sensitization efficiencies.
In a first line of research, we have described and patented the incorporation of tetrazole groups as carboxylic acid replacements for the sensitization of lanthanide emission. We were able to show how the variation of ligand substituents influences the photophysical properties, allowing us to draw predictions and to adapt the structures for improving the emission efficiency. Some of the compounds have been successfully tested in OLED devices.
We also became interested in designing and studying new types of polymetallic architectures based on iridium complexes for the sensitization of lanthanide emission, as well as preliminary investigating the grafting of lanthanide complexes on silicon surfaces.
Discussion on photolysis, Norrish rearrangement, photolysis of azo compounds, isomerization and rearrangement, Fries rearrangement, chemiluminescence and bioluminescence
Modification & Application of Borate Zirconia CatalystRanjeet Kumar
Solid catalysts are of great advantages in alkylation reaction due to heterogenous reaction which makes separation of catalysts very easy and environment friendly. Here, sulfated and borate zirconia catalysts are used to search for ortho-xylene with Toluene & methanol. To find a new path to get o-xylene, catalysts surface was studied and a new mesoporous borate zirconia catalyst was prepared. Mesoporous Borate Zirconia had showed a very efficient path to manufature o-xylene.
Magnetic Fe3O4@MgAl–LDH composite grafted with cobalt phthalocyanine as an ef...Pawan Kumar
Magnetically separable layered double hydroxide MgAl–LDH@Fe3O4 composite supported cobalt
phthalocyanine catalyst was synthesized and used for the aerobic oxidation of mercaptans to corresponding
disulfides under alkali free conditions. The catalyst exhibited excellent activity for the oxidation of
mercaptans using molecular oxygen as an oxidant which can be effectively recovered by using an external
magnetic field. In addition, the covalent immobilization of cobalt phthalocyanine to MgAl–LDH@Fe3O4
support prevents the leaching of the catalyst and improves its activity and stability
SYNGAS PRODUCTION BY DRY REFORMING OF METHANE OVER CO-PRECIPITATED CATALYSTSIAEME Publication
The syngas manufacturing from the reforming of methane with carbon dioxide is tempting because of output in terms of extra pure synthesis gas and lower H2 to CO ratio than other synthesis gas production methods like either partial oxidation or steam reforming. For production of long-chain hydrocarbons though the Fischer-Tropsch synthesis, lower H2 to CO ratio is required and important, as it is a most likely feedstock. In recent decades, CO2 utilization has become more and more important in view of the emergent global warming phenomenon. On the environmental point of view, methane reforming is tantalizing due to the reduction of carbon dioxide and methane emissions as both are consider as dangerous greenhouse gases. Commercially, as cost effectively, nickel is used for methane reforming reactions due to its availability and lower cost compared to noble metals. Number of catalysts endures rigorous deactivation because of carbon deposition. Mainly carbon formation is because of methane decomposition and CO disproportionate. It is important and required to recognize essential steps of activation and conversion of CH4 and CO2 to design catalysts that minimize deactivation. Effect of promoters on activity and stability were studied in the detail. In order to develop the highly active with minimum coke formation the alkali metal oxides and ceria/zirconia/magnesia promoters were incorporated in the catalysts. The influence of ZrO2, CeO2 and MgO, in the performance of Ni-Al2O3 catalyst, prepare by co-precipitation method was studied in detailed. The XRD, FTIR, and BET and reactivity test for different promoted and unprompted catalyst was carried out.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after 24 h irradiation was 9934 μmol g−1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride 145 μmol g−1cat under identical conditions. The presence of triethylamine was found to be vital for the higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for subsequent six runs without significant loss in photo activity.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used
for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after
24 h irradiation was 9934 mmol g1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a
sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride
145 mmol g1cat under identical conditions. The presence of triethylamine was found to be vital for the
higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for
subsequent six runs without significant loss in photo activity.
Metal-organic hybrid: Photoreduction of CO2 using graphitic carbon nitride su...Pawan Kumar
A novel heteroleptic iridium complex supported on graphitic carbon nitride was synthesized and used
for photoreduction of carbon dioxide under visible light irradiation. The methanol yield obtained after
24 h irradiation was 9934 mmol g1cat (TON 1241 with respect to Ir) by using triethylamine (TEA) as a
sacrificial donor, which was significantly higher as compared to the semiconductor carbon nitride
145 mmol g1cat under identical conditions. The presence of triethylamine was found to be vital for the
higher methanol yield. After the reaction, the photocatalyst could easily be recovered and reused for
subsequent six runs without significant loss in photo activity.
Kinetic And Mechanism of Oxidation of Cobalt Metal Complex By Acidic Potassiu...IJMERJOURNAL
ABSTRACT: The Kinetic of oxidation of Cobalt derived from 8-hydroxy quinolone and salicylaldehyde by potassium permanganate has been studied in the presence of acidic medium. The overall reaction is first order with respect to KMnO4, Substrate acid and temperature. No effect of salts has been found suitable mechanism is given.
It contains introduction, homogeneous, heterogenous, transition metal, organometallic, enzymatic and phase transfer catalysis part with certain aspect of greener approach.
It cover approximately all topic according to M.pharm Organic chemistry syllabus, not in advance but for general and basic purpose of understanding.
Investigation on the Growth and Physio-Chemical Properties of L-Alanine Mixed...IJERA Editor
Pure and L-alanine an aminoacid mixed bisthiourea cadmium bromide chloride single crystals were grown by slow evaporation technique. A drastic change in morphology was inferred with the concentration of L-alanine. Mixed crystals have better optical transparency as well as NLO efficiency than the pure BTCBC which were imperative for nonlinear applications. Also L-alanine mixing increases the hardness. The AC conductivity of the grown crystals increases with increasing concentration of L-alanine.
Similar to Synthesis and Application of Heterogeneous Zinc Catalysts for the Decarboxylative Coupling (20)
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Synthesis and Application of Heterogeneous Zinc Catalysts for the Decarboxylative Coupling
1. Synthesis and Application of Heterogeneous
Zinc Catalysts for the Decarboxylative
Coupling
BY
Jagdish Chandra Jat
Registration No: 17mscchm01
Supervisor
Dr. Rakesh Kumar
Central University of Punjab, Bathinda
2. Heterogeneous catalyst
Reactant and catalyst have different phase
Herein we are utilizing biopolymer supported catalyst ie. Chitosan-supported
zinc catalyst
Advantages includes-
i. Easily and effectively catalyst separation
ii. The reaction can occur at milder reaction condition
iii. Environmentally friendly
iv. High possibility of reusing and regenerating catalyst
v. Prevents metal leaching
2
3. Review of Literature
Coupling between Phenylglyoxylic acid, Morpholine, and Phenylacetylene
Cu-catalyzed coupling of glyoxylic acid, amine, and alkyne forming propargylamine
While AuBr3-catalyzed coupling of glyoxylic acid, amine, and alkyne forming
butenolides
Pereshivko, O. P. P., Vsevolod A Van der Eycken, Erik V. (2011).
Unprecedented Cu(I)-catalyzed microwave-assisted three-
component coupling of a oxoacetic acid, an alkyne, and an
amine. Organic Letters, 12: 2638-2641.
Zhang, Q., Cheng, M., Hu, X., Li, B. G., & Ji, J. X. (2010).
Gold-catalyzed three-component tandem process: An
efficient and facile assembly of complex butenolides
from alkynes, amines, and glyoxylic acid. Journal of the
American Chemical Society, 132: 7256-7257.
3
4. Importance of propargylamine
Important building block for the several nitrogen-containing heterocyclic
compounds (such as pyrrole, pyridine, and oxazoles, etc.)
Several biologically active compounds (such as β-lactams, peptides, isosteres,
fungicides, herbicides, etc.)
Natural products (such as paragyline, rasagyline, etc.)
Parkinson’s disease
Alzheimer’s disease
1. Chen, J. J., Swope, D. M., & Dashtipour, K. (20017). A comprehensive review of rasagiline, a
second-generation monoamine oxidase inhibitor, for the treatment of Parkinson's disease.
Clinical Therapeutics, 29: 1825-1849.
2. Weinreb, O., Amit, T., Bar-Am, O., & BH Youdim, M. (2016). Ladostigil: a novel multimodal
neuroprotective drug with cholinesterase and brain-selective monoamine oxidase inhibitory
activities for Alzheimer's disease treatment. Current Drug Targets, 13: 483-494.
4
5. Objectives
To synthesize various chitosan-supported zinc catalysts (Heterogeneous
catalyst)
To study the effect of various chitosan-supported zinc catalysts towards
decarboxylative A3-coupling
5
6. Results and discussion
Catalyst Preparation:
Chitosan-supported Zinc nitrate [Zn(NO3)2] catalyst
Chitosan-supported Zinc chloride [ZnCl2] catalyst
Catalyst Characterization:
FT-IR
UV-Visible
FE-SEM
FE-SEM-EDS
ICPMS (Zinc content in the Chit@Zn(NO3)2 and Chit@ZnCl2 is 2.94 wt%
and 4.41 wt% respectively)
6
8. Screening of catalytic activity
Comparison of catalytic activity of Chit@Zn(NO3)2 and Chit@ZnCl2 catalysts
for the synthesis of propargylamine through decarboxylative A3-coupling
reaction
Here Chit@Zn(NO3)2 shows better reactivity than that of Chit@ZnCl2, so
we further optimized Chit@Zn(NO3)2 catalyst
8
12. Mechanism for decarboxylative A3-coupling
Yadav, J. S., Reddy, B. V. S., Naveenkumar, V., Rao, R. S., & Nagaiah, K. (2004). [bmim] PF6/CuBr: a novel and
recyclable catalytic system for the synthesis of propargyl amines. New Journal of Chemistry, 28: 335-337.12
14. Conclusions
By above-optimized results, it is noted that our best optimization condition
involves phenylglyoxylic acid (1.1 mmol), morpholine (1.0 mmol), and
phenylacetylene (1.5 mmol) catalyzed by Chit@Zn(NO3)2 (10 mg) under the
solvent-free condition for 4 h
To investigate the decarboxylative pathway, we designed a controlled
experiment between phenylglyoxylic acid (1.1 mmol) and morpholine (1.0 mmol)
and observed that it formed benzaldehyde and no Phenylglyoxylic acid was
detected
The propargylamine synthesis via decarboxylative A3-coupling of phenylglyoxylic
acid, amine, and alkyne is an efficient and atom-economical strategy
In this work, we have explored various chitosan-supported zinc catalysts, ionic
liquid, and solvents for the decarboxylative three-component coupling reaction
The reaction could be successfully achieved under the solvent-less condition
with Chit@Zn(NO3)2 catalyst
14