Catalytic C-H amination at its limits: challenges and solutions

organic chemistry, Uncategorized Comments Off

Nov 232017

Catalytic C-H amination at its limits: challenges and solutions

Org. Chem. Front., 2017, 4,2500-2521
DOI: 10.1039/C7QO00547D, Review Article

Damien Hazelard, Pierre-Antoine Nocquet, Philippe Compain
Pushing C-H amination to its limits fosters innovative synthetic solutions and offers a deeper understanding of the reaction mechanism and scope.

Catalytic C–H amination at its limits: challenges and solutions

Damien Hazelard,^a Pierre-Antoine Nocquet^a and Philippe Compain*^a

*Corresponding authors

^aLaboratoire de Synthèse Organique et Molécules Bioactives (SYBIO), Université de Strasbourg/CNRS (UMR 7509), Ecole Européenne de Chimie, Polymères et Matériaux (ECPM), 25 rue Becquerel, 67087 Strasbourg Cedex 2, France
E-mail: philippe.compain@unistra.fr

Abstract

Catalytic C–H amination reactions enable direct functionalization of non-activated C(sp³)–H bonds with high levels of regio-, chemo- and stereoselectivity. As a powerful tool to unlock the potential of inert C–H bonds, C–H amination chemistry has been applied to the preparation of synthetically challenging targets since major simplification of synthetic sequences are expected from this approach. Pushing C–H amination to its limits has led to a deeper understanding of the reaction mechanism and scope. In this review, we present a description of the specific challenges facing catalytic C–H amination in the synthesis of natural products and related compounds, as well as innovative tactics created to overcome them. By identifying and discussing the major insights gained and strategies designed, we hope that this review will stimulate further progress in C–H amination chemistry and beyond.

Conclusion Since the seminal works of Du Bois in the early 2000s, the pace of discovery in the field of metal-catalysed C–H amination has been breath-taking. Not surprisingly, this synthetic tool has been applied to the total synthesis of many compounds of interest, given the high prevalence of the amino group in natural products and synthetic pharmaceuticals.67 Chemist’s confidence in the high potential of the C–H amination methodology to unlock inert C–H bonds has been demonstrated by its application to more and more challenging substrates. This has been a powerful drive for progress in the field. New valuable insights have been gained allowing, for example, a better regiochemical control via stereoelectronic and/or conformational effects. Innovative strategies have been discovered to direct the insertion event in substrates bearing a large degree of attendant functionality. Solutions have spanned from the elegant exploitation of kinetic isotope effects to the tactical use of protecting groups with different sizes or electronic characteristics. Systematic exploration of different catalytic systems has been also performed leading to the opening of new possibilities in C–H amination technology. Manganese-based catalysts have thus given rise to nitrenoids that overcome the low reactivity of primary aliphatic C–H bonds without interfering with weaker secondary/tertiary C–H bonds. Despite these impressive achievements, much remains to be done. Counterintuitive selectivity and unexplained reactivity should serve as a reminder that further studies are highly needed to understand in depth catalytic C–H amination chemistry. Many challenges remain on the way, from basic to applied research. A clear mechanistic view based on definitive evidence concerning the details of the C–N bond forming process would undoubtedly facilitate the rational design of efficient catalytic systems leading to higher regio-, chemio- and stereoselectivity. In particular, the quest for site-selective C–H amination through catalyst control has to be pursued.10d,e In this context, the development of efficient intermolecular C–H amination process still represents a major challenge and upcoming advancements are expected to increase the impact of this technology in organic synthesis. Future progress made in the field of catalytic C–H amination chemistry might also lead to industrial-scale applications in the next decade. It is likely that total synthesis of synthetically challenging targets related to natural products will continue to be a powerful driving force towards this goal.

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“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

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Highly active, separable and recyclable bipyridine iridium catalysts for C–H borylation reactions

spectroscopy, SYNTHESIS, Uncategorized Comments Off

Nov 212017

Graphical abstract: Highly active, separable and recyclable bipyridine iridium catalysts for C–H borylation reactions

Highly active, separable and recyclable bipyridine iridium catalysts for C–H borylation reactions

Hind Mamlouk,^a Jakkrit Suriboot,^b Praveen Kumar Manyam,^a Ahmed AlYazidi,^a David E. Bergbreiter*^b and Sherzod T. Madrahimov*^a

*Corresponding authors

^aDepartment of Chemistry, Texas A&M University at Qatar, P.O. Box 23874, Doha, Qatar
E-mail: sherzod.madrahimov@qatar.tamu.edu

^bDepartment of Chemistry, Texas A&M University, College Station, USA
E-mail: bergbreiter@tamu.edu

Abstract

Iridium complexes generated from Ir(I) precursors and PIB oligomer functionalized bpy ligands efficiently catalyzed the reactions of arenes with bis(pinacolato)diboron under mild conditions to produce a variety of arylboronate compounds. The activity of this PIB bound homogeneous catalyst is similar to that of an original non-recyclable catalyst which allows it to be used under milder conditions than other reported recyclable catalysts. This oligomer-supported Ir catalyst was successfully recovered through biphasic extraction and reused for eight cycles without a loss of activity. Biphasic separation after the initial use of the catalyst led to an insignificant amount of iridium leaching from the catalyst to the product, and no iridium leaching from the catalyst was observed in the subsequent recycling runs. Arylboronate products obtained after extraction are sufficiently pure as observed by ¹H and ¹³C-NMR spectroscopy that they do not require further purification.

Hind MAMLOUK, PhD

R&D in Organic Materials Chemistry Looking for a New Challenge

3-Chloro-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)anisole (5). Transparent oil. Yield: 87%.

1H NMR (600 MHz, CDCl3) δ 7.37 (s, 1H), 7.22 – 7.16 (m, 1H), 6.99 (s, 1H), 3.82 (s, 3H), 1.34 (s, 12H);

13C NMR (101 MHz, CDCl3) δ 159.88, 134.57, 126.84, 117.71, 117.43, 84.15, 55.52, 24.82.

GCMS: RT=14.55 min, M+ = 268.1 vs MW= 268.54 g.mol-1 .

Sherzod Madrahimov

Asst. Prof.

Texas A&M University at Qa… , Doha · Science

Research experience

Aug 2015–present

Asst. Prof.

Texas A&M University at Qatar · Chemistry

Qatar · Doha
Jul 2012–Jul 2015

PostDoc Position

Northwestern University · Department of Chemistry

United States · Evanston
Aug 2007–Jul 2012

Graduate student

University of Illinois, Urbana-Champaign · Department of Chemistry

United States · Urbana

Texas A&M University at Qatar

David Bergbreiter
Professor

Contact

Department of Chemistry
Texas A&M University
College Station, TX 77843-3255

P: 979-845-3437
F: 979-845-4719
bergbreiter@chem.tamu.edu

Current Activities

Our group explores new chemistry related to catalysis and polymer functionalization using the tools and precepts of synthetic organic chemistry to prepare functional oligomers or polymers that in turn are used to either effect catalysis in a greener, more environmentally benign way or to more efficiently functionalize polymers. Often this involves creatively combining the physiochemical properties of a polymer with the reactivity of a low molecular weight compound to form new materials with new functions. These green chemistry projects involve undamental research both in synthesis and catalysis but has practical aspects because of its relevance to practical problems.

A common theme in our catalysis studies is exploring how soluble polymers can facilitate homogeneous catalysis. Homogeneous catalysts are ubiquitously used to prepare polymers, chemical intermediates, basic chemicals and pharmaceuticals. Such catalysts often use expensive or precious metals or expensive ligands or are used at relatively high catalyst loadings. The products often contain traces of these catalysts or ligands – traces that are undesirable for esthetic reasons or because of the potential toxicity of these impurities. Both the cost of these catalysts of these issues require catalyst/product separation – separations that often are inefficient and lead to chemical waste. These processes also use volatile organic solvents – solvents that have to be recovered and separated. Projects underway in our lab explore how soluble polymers can address each of these problems. Examples of past schemes that achieve this goal in a general way as highlighted in the Figure below.

We also use functional polymers to modify existing polymers. Ongoing projects involve molecular design of additives that can more efficiently modify polymers’ physical properties. We also use functional polymers in covalent layer-by-layer assembly to surface polymers’ surface chemistry. An example of this work is our use of ‘smart’ polymers that reversibly change from being water soluble cold to being insoluble and hydrophobic on heating. Such polymers’ have been used by us to prepare ‘smart’ catalysts, ‘smart’ surfaces and membranes, and to probe fundamental chemistry underlying temperature and salt-dependent protein solvation.

Jakkrit Suriboot

Research Assistant at Texas A&M University

Image result for Praveen Kumar Manyam TEXAS

Dr. Praveen Kumar

Title: Research Assistant Professor

Education: M.S., I.I.T. Roorkee
Ph.D., Panjab University Chandigarh (2008)
Visiting Fellow (w/ Prof. G. G. Balint-Kurti), Bristol University, UK
Postdoctoral Research Associate (w/ Prof. Svetlana Malinovskaya), Stevens Institute of Technology, Hoboken, NJ
Senior Postdoctoral Research Associate (w/ Prof. Seogjoo Jang), Queens College of CUNY, NY

Office: Chemistry 010

Phone: 806-742-3124

Email: praveen.kumar@ttu.edu

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“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

amcrasto@gmail.com

Biovis PSA2000 Automated Particle Size Analysis System (The 21 CFR Part 11 compliance module )

Uncategorized Comments Off

Nov 122017

Inline images 1

Biovis PSA2000

Automated Particle Size Analysis System

Biovis PSA 2000 system designed to provide particle size and shape analysis with more than 70 measurements on size shape and color makes it a unique solution for R&D and QC applications in Pharmaceutical, Food processing, Paint , Ink Coating and many other applications. The 21 CFR Part 11 compliance module make it more preferred for the Manufacturing plants working under USFDA guidelines. Report available on request, or download link available below, it is as per the regulatory requirements.

For R&D the non FDA version of the software can provide huge amount of data which can be mined to help find more information about the particulate matter based on its size and shape thereby improve the Drug delivery, Process Engineering , process development etc…

Biovis PSA2000 is an automated particle size analysis system for comprehensive investigation of different types of dry or wet particulate matter such as fibres, emulsions, crystals, powders, spray droplets, or suspensions, etc.

– Rapid automated analysis of thousands of individual particles

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– Custom built analysis routines to handle specific sample types

– Detect and classify particle types on the basis of size, shape, color

– Professional Analysis Report generation

The Biovis PSA 2000 system with Biovis Particle Plus Ver 5.3 has the following features

Reports with D10, D50, D90 values.
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Departments that can benefit from Biovis PSA 2000 system are

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Imaging Solutions

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Image Analysis Software are used in the field of Pathology, MicroBiology, research & quality control of Medicine, Forensic sciences, etc.
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Microstructural image analysis is useful in Steel Industry, Metal Strength Analysis, manufacturing, automotive, quality control of materials, and for Metallurgist in material science applications.

Biovis Materials Plus

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Naveen Hegde

Regards

Naveen Hegde

Expert Vision Labs

H202, Ranjit Studio,

DP Road, Dadar East,

Mumbai 400014

India.

Tel:+91 22 6637 2739 / +91 22 6637 1470

Mobile: +91 93240 51848

Fax : +91 22 6637 2739

Website : www.expertvisionlabs.com

email : nhegde@expertvisionlabs.com

Expert Vision Labs

Expert Vision Labs has pioneered Image Analysis Technology in India and has focus into developing, a flexible line of highly cost effective and quality software driven products for Research and Industrial customers in India and across the globe.
Established in 1995, Expert Vision Labs has strived to specialize in providing complete solutions for computer based imaging and vision related applications. Have developed the

Biovis

image analysis product line for diverse applications in genetics, bioscience, material science and industrial applications.

Report available on request, or download here is as per the regulatory requirements.
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“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

amcrasto@gmail.com

Synthesis with Catalysts

Uncategorized Comments Off

Nov 112017

Axay Parmar

Founder at Synthesis with Catalysts Pvt. Ltd

axayrp@gmail.com

+91- 999-997-2051

info@synthesiswithcatalysts.com

Synthesis with Catalysts Pt. Ltd. is a company started with an aim to produce chiral and achiral precious metal based catalysts on commercial scale in line with “Clean and Green India” and “Make in India” vision of Government of India. These catalysts have been developed to promote efficient, economical and environmentally benign processes for the target compounds being produced in aroma, fine chemicals and pharmaceutical industries. These catalysts and their intermediates are also extensively used in academic and industrial R&D centres across globe. In India these catalysts are currently imported at a very prohibitive cost, due to which their use is limited for want of funds. In this direction Synthesis with Catalysts Pvt. Ltd. is striving to make these products available to indigenously available at a very competitive price at small and bulk scale. We are also doing in-house research to optimize process parameters ofvarious organic transformations particularly asymmetric hydrogenation and isomerization reactionsfor customers as and when required.

For the list of our products please visit our wesitewww.synthesiswithcatalysts.com

ABOUT US

Our vision is to be the most respected catalyst manufacturing company in the country
Our goal is to help our customers:
to further improve their production methodologies

increase productivity,
develop new products with the intervention of catalysts to make the process green and clean

Highly selective catalysts for intended application
Competitive pricing with short delivery lead times
Custom product and process development

Activities:A

Manufacture of Homogeneous catalysts using metal ions viz. Rh, Pt, Ir, Pd, Ru, Co, and Mn

Manufacture of ligands and intermediates

Pharmaceutical, bulk drugs, API, aroma chemical, essential oil industries served

Focus on chiral chemistries

Gram to kilogram quantities

ASYMMETR

Some of the representative reactions are:

ASYMMETRIC/ CHEMOSELECTIVE HYDROGENATION CATALYSTS

Statements

Catalysts are chiral metal complexes derived from a precious metal ion and chiral ligands
Ru used most frequently, Rh used in some cases to enhance chemo- and enantio- selectivity
Chiral ligands can be selected from variety of simple and substituted BINAP alone or in combination with chiral/achiral diamines
Suggested catalysts:
- RuCl₂[(S)-BINAP](dmf)n
- RuCl₂[(S)- tolBINAP][(S,S)-dpen]
- (S)-XylBINAP/(S)-DAIPEN-Ru
- (S)-XylBINAP/(S,S)-DPEN-Ru
- RuCl₂[(S)-tolBINAP](pica)
- RuCl[(S,S)-TsDPEN](η⁶-p-cymene)
- Ru(OTf)(TsDPEN)(p-cymene)
- BINAP-Ru(II) dicarboxylate complexes

ENANTIOSELECTIVE EPOXIDATION / HKR / DKR

Statements:

Transition metal complexes are used for chiral and non-chiral epoxidation of internal and prochiral olefins
The epoxides are important intermediates for host of industrially important products
In cases where epoxides are required in high optical purity, racemic epoxides can be subjected to Hydrolytic kinetic resolution (HKR), Aminolytic kinetic resolution (AKR), Dynamic kinetic resolutions (DKR)
Suggested catalysts:
- Mn, Co, Cr, Al complexes of chiral SALEN ligands

ASYMMETRIC ISOMERIZATION

Double bond migration reactions

Statements:

Rh-catalyzed asymmetric isomerization of allylic amines into the corresponding enamines is one of the most revered industrial organic transformation in asymmetric catalysis
It has accommodated a wide range of substrates and is a key step in the industrial production of menthol
Other industrially important isomerization is migration of terminal double bond to produce selectively trans-internal olefins
Commercially important products like isoeugenol and trans-anetheole are produced by these transformations
Suggested catalysts:
- Ru(acac)₃
- RuHCl(CO)(PPh₃)₃
- Rh/Pd complexes

Tree of popular asymmetric organic transformations

At Chiral India event in Mumbai where our technical director Dr. Abdi Is a speaker. With Basu Agarwal

Basu Agarwal

CEO at Synthesis with Catalysts Pvt Ltd

basu.ag@gmail.com

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“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

amcrasto@gmail.com

Gram-Scale Synthesis of Amines Bearing a gem-Difluorocyclopropane Moiety

organic chemistry, spectroscopy, SYNTHESIS Comments Off

Nov 102017

Image result for National Taras Shevchenko University of Kyiv, Volodymyrska Street 64, Kyiv 01601, Ukraine

Ukraine

Abstract

The synthesis of monocyclic, spirocyclic and fused bicyclic secondary amines bearing a gem-difluorocyclopropane moiety via difluorocyclopropanation of unsaturated N-Boc derivatives using the trifluoromethyl(trimethyl)silane/sodium iodide [CF₃SiMe₃-NaI] system is described. The relative order of the substrate reactivity is established. It is shown that for the reactive alkenes the standard reaction conditions can be used, whereas for the substrates with low reactivity, slow addition of the Ruppert–Prakash reagent is necessary.

Gram-Scale Synthesis of Amines Bearing a gem-Difluorocyclopropane Moiety

Authors., Pavel S. Nosik,

DOI: 10.1002/adsc.201700857

Pavel S. Nosik,a.b Andrii O. Gerasov,a Rodion O. Boiko,a Eduard Rusanov,b Sergey V. Ryabukhin,c Oleksandr O. Grygorenko,c * Dmitriy M. Volochnyukb

a Spectrum Info Ltd., Life Chemicals Inc., Murmanska Street 5, Kyiv 02094, Ukraine

b Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanska Street 5, Kyiv 02660, Ukraine

c National Taras Shevchenko University of Kyiv, Volodymyrska Street 64, Kyiv 01601, Ukraine

Image result for National Taras Shevchenko University of Kyiv, Volodymyrska Street 64, Kyiv 01601, Ukraine

* Corresponding author. E-mail: gregor@univ.kiev.ua.

Oleksandr Grygorenko

Ph D

Professor (Associate)

National Taras Shevchenko Univ… , Kiev · Faculty of Chemistry

National Taras Shevchenko University of Kyiv, Volodymyrska Street 64, Kyiv 01601, Ukraine

National Taras Shevchenko University of Kyiv

Department

Faculty of Chemistry

Image result for National Taras Shevchenko University of Kyiv, Volodymyrska Street 64, Kyiv 01601, Ukraine

Dmitriy M. Volochnyuk

Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanska Street 5, Kyiv 02660, Ukraine

Dmitriy M. Volochnyuk was born in 1980 in Irpen, Kyiv region, Ukraine. He graduated from Kyiv State Taras Shevchenko University in 2002 and was awarded his M.S. degree in chemistry. He received his Ph.D. in organic chemistry in 2005 from the Institute of Organic Chemistry, National Academy of Sciences of Ukraine under the supervision of Dr. A. Kostyuk for research on the chemistry of enamines. At present, he divides his time between the Institute of Organic Chemisty, as Deputy Head of Organophosphorus Department and Senior Researcher, and Enamine Ltd (Kyiv, Ukraine), as Director of Chemistry. His main scientific interests are related to fluoroorganic, organophosphorus, heterocyclic and combinatorial chemistry, and multistep organic synthesis. He is a coauthor of more than 80 papers

Given that the incorporation of small fluorinated fragments in drug-like molecules continues to rise, this has created an onus on the synthetic community to provide robust, scalable routes to these molecules of interest. Grygorenko and co-workers have reported on a synthesis of amines featuring a gem-difluorocyclopropane moiety using the readily available Ruppert–Prakash reagent ( Adv. Synth. Catal. 2017, 10.1002/adsc.201700857).
Evaluating a series of olefins under the standard reaction conditions in refluxing THF indicated that only the most reactive olefins (gem-disubstituted) provided good yields of the desired cyclopropane, while other solvents proved to be ineffective. Conducting a control experiment omitting the substrate demonstrated that the key issue herein was competitive decomposition of the TMSCF₃ to a series of gaseous byproducts under the reaction conditions.
Whereas continuous flow provides a potential to mitigate against this, the current report demonstrated that slow addition of the reagent to the reaction mixture also provided a practical solution to this problem.
Employing this approach enabled not only excellent conversions and yields to be realized but also allowed reactivity trends to be identified. In general, gem-disubstituted are the most reactive with the trend correlating with steric hindrance.
For other classes of olefins, electronics are the major factor with the ability of the substituents to stabilize a positive charge in the transition state consistent with a nonsynchronous formation of the two sigma bonds in the cycloaddition the key consideration. The removal of the Boc-protecting group under standard acidic conditions provided the amines as their hydrochloride salts.
Eduard Rusanov

PhD

Head of Crystallographic Lab./Director of the crystallographic facility Nat. Acad. of Sci. Ukraine ‘Single Mjlecule Crystallography’ at IOC

Institute of Organic Chemistry… · DEPARTMENT OF PHYSICOCHEMICAL INVESTIGATIONS

tert-Butyl 1,1-difluoro-6-azaspiro[2.5]octane-6-carboxylate (10a):

Yield: 66.7 g (91%) (Method A); off-white crystalline powder: mp 46–48 8C;

1H NMR (CDCl3 , 400 MHz): d= 3.57–3.42 (m, 2H), 3.40–3.27 (m, 2H), 1.66–1.47 (m, 4H), 1.44 (s, J=2.3 Hz, 9H), 1.08 (t, J=8.3 Hz, 2H);

13C NMR (CDCl3, 101 MHz): d=154.2, 115.4 (t, J=288.1 Hz), 79.3, 42.8, 28.4, 28.1, 26.8 (t, J=10.0 Hz), 21.0 (t, J=10.1 Hz);

19F NMR (CDCl3 , 376 MHz): d=@140.6;

MS (EI): m/z= 247 (M+ ), 192 (M+@t-Bu), 174 (M+@t-BuO), 147 (M+@Boc), 127 (M+@Boc@HF);

Anal. calcd. for C12H19F2NO2 : C 58.29, H 7.74, N 5.66; found: C 58.49, H 8.02, N 5.30.

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2-Phenylfuran

spectroscopy, SYNTHESIS Comments Off

Nov 092017

2-Phenylfuran

17113-33-6 cas

2-Phenylfuran (3v) [15]: According to the general procedure I and purification by column chromatography (100% PE) yielded 3v (35.9 mg, 50%) and the general procedure II yielded 3s (35.1 mg, 49%) as a white solid . 1 H NMR (400 MHz, CDCl3) δ 7.68-7.66 (m 2H), 7.46 (s, 1H), 7.40-7.35 (m, 2H), 7.26-7.23 (m, 1H), 6.645-6.639 (m, 1H), 6.461-6.457 (m, 1H). LRMS (ESI) calcd for [M+H]+ C10H9O 145.1, found 145.1.

15 Zhou, C.-Y.; Chan, P. W. H.; Che, C.-M. Org. Lett. 2006, 8, 325.

Visible-Light Photoredox in Homolytic Aromatic Substitution: Direct Arylation of Arenes with Aryl Halides

Yannan Cheng, Xiangyong Gu, and Pixu Li*

Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering, and Materials Science, Soochow University, 199 RenAi Road, Suzhou, Jiangsu 215123, China

Org. Lett., 2013, 15 (11), pp 2664–2667

DOI: 10.1021/ol400946k

lipixu@suda.edu.cn

Abstract

Direct arylation of unactivated arenes or heteroarenes with aryl halides could be carried out in the presence of potassium tert-butoxide and dimethyl sulfoxide under visible-light irradiation. Ir(ppy)₃was found to be an effective photoredox catalyst for this reaction. The reactions of aryl iodides occurred at room temperature. Elevated temperature was required for aryl bromides. Homolytic aromatic substitution was proposed to be the operative reaction pathway.

Predicts

1H NMR

13C NMR

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http://pubs.acs.org/doi/10.1021/ol400946k

more info

1H NMR spectrum of C10H8O in CDCL3 at 400 MHz. Click to toggle size.

Shifts

Index	Name	Shift (ppm)
19	H7	6.582
1	H1	7.655
5	H5	7.655
15	H6	6.885
11	H2	7.415
7	H4	7.415
9	H3	7.362
17	H8	7.471

“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

Transition-Metal-Free Cross-Coupling of Aryl and Heteroaryl Thiols with Arylzinc Reagents

spectroscopy, SYNTHESIS, Uncategorized Comments Off

Nov 092017

Zhong-Xia WANG

N,N-dimethyl-4-biphenylamine

(1) N,N-dimethyl-[1,1′-biphenyl]-4-amine (3a) 5,6

Elute: EtOAc/petroleum ether: 1/100 (v/v), white solid, yield 97.8 mg (99%).

1H NMR (400 MHz, CDCl3): δ 7.56 (d, J = 7.8 Hz, 2H), 7.51 (d, J = 8.8 Hz, 2H), 7.40 (t, J = 7.7 Hz, 2H), 7.30–7.21 (m, 1H), 6.81 (d, J = 8.8 Hz, 2H), 3.00 (s, 6H).

13C NMR (101 MHz, CDCl3): δ 150.09, 141.34, 129.37, 128.78, 127.84, 126.43, 126.12, 112.90, 40.97.

5 Yang, X.; Wang, Z.-X. Organometallics 2014, 33, 5863.

(6) Stibingerova, I.; Voltrova, S.; Kocova, S.; Lindale, M.; Srogl, J. Org. Lett. 2016, 18, 312.

Transition-Metal-Free Cross-Coupling of Aryl and Heteroaryl Thiols with Arylzinc Reagents

Bo Yang^† and Zhong-Xia Wang^*^†^‡

^† CAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical Sciences at Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China

^‡ Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, P. R. China

Org. Lett., Article ASAP

DOI: 10.1021/acs.orglett.7b03145

*E-mail: zxwang@ustc.edu.cn.

Abstract

Cross-coupling of (hetero)arylthiols with arylzinc reagents via C–S cleavage was performed under transition-metal-free conditions. The reaction displays a wide scope of substrates and high functional-group tolerance. Electron-rich and -deficient (hetero)arylthiols and arylzinc reagents can be employed in this transformation. Mg²⁺ and Li⁺ ions were demonstrated to facilitate the reaction.

In summary, we developed a transition-metal-free coupling reaction of (hetero)arylthiols with arylzinc reagents to form bi(hetero)aryls. The reaction exhibited wide substrate scope and good compatibility of functional groups. Electron-rich and -poor aryl or heteroaryl thiols can be converted. Various arylzinc reagents, including electron-rich and electron-poor reagents, can be employed as the coupling partners. Preliminary mechanistic studies suggest a nucleophilic aromatic substitution pathway, and Mg²⁺ and Li⁺ ions play important roles in the process of reaction. This study provides an example of S^2– as a leaving group in an aromatic system and an effective methodology for the synthesis of bi(hetero)aryls including pharmaceutical molecules without transition-metal impurities.

Zhong-Xia WANG


	Department：	Department of Chemistry
	Mailing Address：	Department of Chemistry, University of Science and Technology of China, 96 Jinzhai Rd, Hefei, Anhui, 230026, PR China
	Postal Code：	230026
	Phone：	+86-551-63603043
	Fax：
	Homepage：	http://chem.ustc.edu.cn/szdw_16/bd/201210/t20121023_142877.html

Zhong-Xia Wang is a professor in the Department of Chemistry at the University of Science and Technology 
of China. He received his BS degree (1983) and MS degree (1986) from Nankai University, 
and PhD degree (1997) from the University of Sussex, UK. Since July 1986, Wang has been working 
at the University of Science and Technology of China (USTC) successively as Assistant, 
Lecturer, Associate Professor, and Professor. From Aug. 1993 to Oct. 1996, he pursued his doctoral 
studies at the University of Sussex, UK, and from Oct. 1999 to Oct. 2000, he was a Research Associate 
at the Chinese University of Hong Kong.

 学 系
Department of Chemistry

Predicts

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http://pubs.acs.org/doi/10.1021/acs.orglett.7b03145

“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

Benzisoxazole: a privileged scaffold for medicinal chemistry

new drugs, organic chemistry, SYNTHESIS, Uncategorized Comments Off

Nov 082017

Benzisoxazole: a privileged scaffold for medicinal chemistry

Med. Chem. Commun., 2017, Advance Article
DOI: 10.1039/C7MD00449D, Review Article

K. P. Rakesh, C. S. Shantharam, M. B. Sridhara, H. M. Manukumar, Hua-Li Qin
The benzisoxazole analogs represent one of the privileged structures in medicinal chemistry and there has been an increasing number of studies on benzisoxazole-containing compounds.

Benzisoxazole: a privileged scaffold for medicinal chemistry

K. P. Rakesh,^a C. S. Shantharam,*^b M. B. Sridhara,^c H. M. Manukumar^d and Hua-Li Qin*^a

*Corresponding authors

^aDepartment of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan, PR China
E-mail:qinhuali@whut.edu.cn
Fax: +86 27 87749300

^bDepartment of Chemistry, Pooja Bhagavath Memorial Mahajana Education Centre, Mysuru-570016, India
E-mail:shantharamcs@gmail.com
Tel: +91 8904386977

^cDepartment of Chemistry, Rani Channamma University, Vidyasangama, Belagavi-591156, India

^dDepartment of Studies in Biotechnology, University of Mysore, Manasagangotri, Mysuru-570006, India

Abstract

The benzisoxazole analogs represent one of the privileged structures in medicinal chemistry and there has been an increasing number of studies on benzisoxazole-containing compounds. The unique benzisoxazole scaffold also exhibits an impressive potential as antimicrobial, anticancer, anti-inflammatory, anti-glycation agents and so on. This review examines the state of the art in medicinal chemistry as it relates to the comprehensive and general summary of the different benzisoxazole analogs, their use as starting building blocks of multifarious architectures on scales sufficient to drive human drug trials. The number of reports describing benzisoxazole-containing highly active compounds leads to the expectation that this scaffold will further emerge as a potential candidate in the field of drug discovery.

Hua-Li Qin

Dr. Hua-Li Qin Ph. D 2009
qinhuali@bu.edu

Department of Pharmaceutical Engineering, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan, PR China

Hua-Li joined the Panek group in 2005.

B.S. Chemistry Engineering 2000
M.S. Chemistry 2004 University of Science & Technology of China

C. S. Shantharam

M.Sc., Ph.D

Assistant professor

Pooja Bhagavat Memorial Mahaja… , Mysore · Department of Chemistry

Department of Chemistry, Pooja Bhagavath Memorial Mahajana Education Centre, Mysuru-570016, India

Hua-Li Qin

Manukumar H M

Master of Science

Research Scholar

University of Mysore , Mysore · Department of Biotechnology

////////////Benzisoxazole, scaffold, medicinal chemistry

“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

Metal-free synthesis of polysubstituted pyrroles using surfactants in aqueous medium

organic chemistry, SYNTHESIS Comments Off

Nov 072017

Metal-free synthesis of polysubstituted pyrroles using surfactants in aqueous medium

Green Chem., 2017, Advance Article
DOI: 10.1039/C7GC01874F, Communication

Amrendra Kumar, Ramanand, Narender Tadigoppula
An efficient and metal-free method has been developed for the synthesis of polysubstituted pyrrole derivatives with combination of sodium dodecyl sulphate (SDS) and Triton X-100 surfactants using water as a solvent at room temperature in 2-6 h and under microwave conditions (10 min) with good to excellent yields.

http://pubs.rsc.org/en/Content/ArticleLanding/2017/GC/C7GC01874F?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

Metal-free synthesis of polysubstituted pyrroles using surfactants in aqueous medium

Amrendra Kumar,^a Ramanand^a and Narender Tadigoppula*^a

*Corresponding authors

^aMedicinal and Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow-226 031, India
E-mail: t_narendra@cdri.res.in
Tel: +91-522-2772450 Ext: 4737

Dr. Narender Tadigoppula

Principal Scientist
Medicinal & Process Chemistry
Central Drug Research Institute
India

Dr. Narender Tadigoppula is currently principal scientist in the department of medicine chemistry central drug research institute. He published more than 30 research articles. His major major research activities are identification of biologically active lead molecules through activity guided fraction and isolation work on the medicinal plants, marine organisms and microorganisms for metabolic diseases (hyperglycemia, dyslipidemia), parasitic diseases (leishmania and malaria), cancer etc., and chemical transformation of natural products of biological importance to improve their potency. We synthesize these biologically active lead molecules and their analogues in our laboratory. We have identified several lead molecules from the Indian medicinal plants for various disease areas as described below and further work is in progress to develop natural products based drugs.

Abstract

An efficient and metal-free method has been developed for the synthesis of polysubstituted pyrrole derivatives via intermolecular cycloaddition of substituted 1-phenyl-2-(phenylamino)-ethan-1-one/1-phenyl-2-(phenylamino)-propan-1-ones/2-((4-methoxyphenyl)amino)-1-(thiophen-2-yl)ethan-1-one/1-(furan-2-yl)-2-((4-methoxyphenyl)amino)ethan-1-one/1-(benzofuran-3-yl)-2-((4-methoxyphenyl)amino)ethan-1-one and dialkyl acetylene dicarboxylate/ethylbutynoate in the presence of a combination of sodium dodecyl sulphate (SDS) and Triton X-100 surfactants using water as a solvent at room temperature in 2–6 h under microwave conditions (10 min) with good to excellent yields.

Diethyl-1-(4-methoxyphenyl)-4-(p-tolyl)-1H-pyrrole 2,3dicarboxylate

white solid, yield 77%, mp 128-130 ;

1H NMR (400 MHz, CDCl3) δ 7.38(d, J = 8.2,2H), 7.31 (d, J = 7.9, 2H), 7.21 (d, J = 7.12, 2H), 6.99-6.96 (m, 3H), 4.31 (q, J = 7.2 Hz, 2H), 4.12 (q, J = 7.6Hz, 2H), 3.88 (s, 3H), 2.38 (s, 3H), 1.31 (t, J = 7.9Hz, 3H), 1.19 (t, J = 7.5Hz, 3H) ;

13C NMR (100 MHz, CDCl3) δ 166.3, 159.9, 149.0, 148.8, 136.7, 132.6, 130.3, 129.2, 127.6, 125.8, 124.5, 123.4, 121.5, 118.3, 110.5, 110.2, 61.2, 60.7, 56.0, 21.1, 14.0, 13.9.

IR (KBr) ṽ (cm-1): 2981.9, 1717.9, 1514.1, 1419.2, 1381.3, 1245.0, 1175.9, 1226.7, 1043.6, 835.7, 755.3, 663.

HRESIMS: m/zcalcd for [M+H]+ C24H26NO5 408.1805 found 408.1845.

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O=C(OCC)c2c(c(cn2c1ccc(OC)cc1)c3ccc(C)cc3)C(=O)OCC

“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

An efficient green protocol for the synthesis of tetra-substituted imidazoles catalyzed by zeolite BEA: effect of surface acidity and polarity of zeolite

spectroscopy, SYNTHESIS, Uncategorized Comments Off

Nov 032017

Image result for Kalpana C. Maheria sv

1-benzyl-2, 4, 5-triphenyl-1H-imidazole

. 1-Benzyl-2,4,5-triphenyl-1H-imidazole (5a, n = 1).

Off-white solid; m.p.: 160–162 °C;

anal. calcd. for C28H22N2: C, 87.01, H, 5.74, N, 7.25%. Found: C, 87.13, H, 5.70, N, 7.19%;

UV (λmax, ethanol) = 280 nm;

FT-IR (KBr, cm−1 ): 3060 (C–H stretch), 3031, 1600 (CN), 1497, 1483, 1447 (CC), 1352 (C–N stretch), 769, 697 (C–H band);

1 H NMR (400 MHz, DMSO): 5.16 (s, 2H, CH2), 6.74–7.67 (m, 20H, Ar–H) ppm;

13C NMR (100 MHz, DMSO): 47.6 (CH2, C8), 125.1 (CHarom, C28), 126.0 (CHarom, C26), 126.2 (CHarom, C30), 126.4 (CHarom, C11), 127.0 (CHarom, C15), 127.1 (CHarom, C16), 127.7 (CHarom, C20), 128.0 (CHarom, C21), 128.1 (CHarom, C25), 128.4 (CHarom, C13), 128.5 (CHarom, C18), 128.6 (CHarom, C27), 128.8 (C1), 128.8 (CHarom, C12), 128.9 (CHarom, C14), 130.1 (CHarom, C17), 130.3 (CHarom, C19), 130.5 (CHarom, C22), 130.7 (CHarom, C24), 131.0 (CHarom, C29), 134.4 (CHarom, C9), 135.1 (CHarom, C23), 136.8 (CHarom, C7), 137.0 (CHarom, C10), 137.2 (CHarom, C6), 145.4 (C2), 147.0 (C4) ppm;

MS: m/z = 387.5 (M + H)+

An efficient green protocol for the synthesis of tetra-substituted imidazoles catalyzed by zeolite BEA: effect of surface acidity and polarity of zeolite

Jenifer J. Gabla,^a Sunil R. Mistry^b and Kalpana C. Maheria*^a

Jenifer J Gabla

S V National Institute of Technology, India

Jenifer J Gabla has obtained her MSc degree in Organic Chemistry, in the year 2013 from Uka Tarsadia University, Bardoli, Gujarat. She is currently pursuing her PhD in the area of solid acid catalyzed multicomponent reactions for the synthesis of biologically active drug molecules, at Applied Chemistry Department (ACD), S. V. National Institute of Technology (SVNIT) under the guidance of Kalpana Maheria, Assistant Professor & Head, ACD, SVNIT, Surat, Gujarat, India. Her research focuses on development of novel zeolite based catalytic materials and exploring their utility in the green process development for the synthesis of medicinal compounds. She has presented her research in several national and international conferences.

Kalpana C. Maheria

*Corresponding authors

^aApplied Chemistry Department, S. V. National Institute of Technology, Ichchhanath, Surat – 395007, India
E-mail:kcmaheria@gmail.com

^bMandvi Science College, Mandvi – 394160, Surat, India

Abstract

In the present study, the catalytic activity of various medium (H-ZSM-5) and large pore (H-BEA, H-Y, H-MOR) zeolites were studied as solid acid catalysts. The zeolite H-BEA is found to be an efficient catalyst for the synthesis of 1-benzyl-2,4,5-triphenyl-1H-imidazoles through one-pot, 4-component reaction (4-CR) between benzil, NH₄OAc, substituted aromatic aldehydes and benzyl amine. The hydrophobicity, Si/Al ratio and acidic properties of zeolite BEA were well improved by controlled dealumination. The synthesized materials were characterized by various characterization techniques such as XRD, ICP-OES, BET, NH₃-TPD, FT-IR, pyridine FT-IR, ²⁷Al and ¹H MAS NMR. It has been observed that the dealumination of the parent zeolite H-BEA (12) results in the enhanced strength of Brønsted acidity up to a certain Si/Al ratio which is attributed to the inductive effect of Lewis acidic EFAl species, leading to the higher activity of the zeolite BEA (15) catalyst towards the synthesis of 1-benzyl-2,4,5-triphenyl-1H-imidazoles under thermal solvent-free conditions with good to excellent yields. Using the present catalytic synthetic protocol, diverse tetra-substituted imidazoles, which are among the significant biologically active scaffolds, were synthesized in high yield within a shorter reaction time. The effect of polarity, surface acidity and extra framework Al species of the catalysts has been well demonstrated by means of pyridine FT-IR, and ²⁷Al and ¹H MAS NMR. The solvent-free synthetic protocol makes the process environmentally benign and economically viable.

Image result for S. V. National Institute of Technology, Ichchhanath, Surat

S. V. National Institute of Technology, Ichchhanath, Surat

Mandvi Science College, Mandvi – 394160, Surat, India

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DISCLAIMER

“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent