Recent progress on fluorination in aqueous media

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Jul 312017

Recent progress on fluorination in aqueous media

Green Chem., 2017, Advance Article
DOI: 10.1039/C7GC01566F, Tutorial Review

Lian Yang, Tao Dong, Hrishikesh M. Revankar, Cheng-Pan Zhang
Advances of fluorination in aqueous media during the last few decades are summarized in this review

Recent progress on fluorination in aqueous media

Lian Yang,^a Tao Dong,^a Hrishikesh M. Revankar^a and Cheng-Pan Zhang*^a

*Corresponding authors

^aSchool of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan, China
E-mail: cpzhang@whut.edu.cn, zhangchengpan1982@hotmail.com

Abstract

Advances in aqueous fluorination during the last few decades are summarized in this review. Fluorinated compounds have dominated a large percentage of agrochemicals and pharmaceuticals and a mass of functional materials. The incorporation of fluorine atoms into organic molecules has become one of the mainstream technologies for their functional modification. Water is very environmentally friendly and has advantageous physicochemical properties. Fluorination reactions in aqueous media are highly sought-after, and have attracted great attention in research areas ranging from medicinal chemistry to materials science. In early times and for a long time, fluorination was thought to be diametrically opposed to water or moisture. However, recent examples have conflicted with this viewpoint. The successful merger of “untamed” fluorine and “mild” water in chemical reactions has set up a new prospect for green chemistry. A considerable amount of remarkable research works have been carried out using water as a (co)solvent and/or a reactant for transformations including electrophilic, radical, or nucleophilic fluorination. We hope that this review will serve as a guide to better understand and to further broaden the field of fluorine chemistry in aqueous conditions.

Conclusion

The installation of fluorine atoms into organic and organometallic frameworks can dramatically change their physical, chemical, and biological properties. Organofluorides have entered many fields of science and technology with a tremendous impact on these domains. The development of efficient, selective, and mild methods to build C-F bonds is of great importance, which is highly desirable to keep up with the rapidly growing demand of novel fluorine-containing scaffolds. In early times, most fluorination reactions required harsh conditions and moisture-sensitive, highly toxic, and explosive atomic fluorine transfer agents like fluorine gas, xenon difluoride, hypofluorite, antimonytrifluoride, and diethylaminosulfurtrifluoride. The discovery of stable electrophilic fluorination reagents such as Selectflour and NFSI has remarkably changed the dilemma, which realized a large number of safe, mild, and easily controllable electrophilic and radical fluorination reactions in aqueous media. Although the exact mechanisms are still unclear at present, it does never hamper the green fluorination method development with these reagents. A mass of successful examples have confirmed that the aqueous reaction medias have positive impacts on electrophilic and radical fluorination reactions with using the N-F reagents and in many cases water can also be a nucleophile for the entire conversions.

In addition, water was generally thought to be an unsuitable medium for nucleophilic fluorination because the fluoride ions can be “trapped” in aqueous medias by hydrogen bonding and become unreactive. Thus, their use in organic synthesis has been quite limited to polar aprotic solvents. Although the strong hydrogen bond formed between fluoride and water diminished the nucleophilicity of fluoride ions, the recent examples of nucleophilic fluorination in aqueous media have implied that this “negative” effect does not always harm the reaction. Besides, the radioisotope 18F has been considered to be a good choice for PET imaging owing to its desirable radiochemical properties. With a half-life of 110 minutes, the introduction of [ 18F]fluorine atoms into biomolecules has to be completed in a swift manner to minimize the loss of radioactivity. Nucleophilic incorporation of [18F]F‒ in aqueous conditions could rapidly produce [18F]fluorinesubstituted biomolecules, which avoided azeotropic drying process, shortened the production time, and minimized the loss of activity. We summarized the recent aqueous fluorination reactions in three sections according to their possible mechanisms. The successful amalgamation of “ill-tempered” fluorine and “benign” water has boded well for green fluorine chemistry. Water behaves as a cosolvent to dissolve fluorination reagents and/or as a reactant for bifunctionalization. Since the aspects of green chemistry has drawn much attention from the society, the pursuit of more efficient and milder reaction conditions for greener fluorination in aqueous medias will never end. Although a large number of research works have been published in this area, it’s only the tip of the iceberg with a wide scope for improvement. We hope that this review will serve as a guide to understand and to further broaden the field of aqueous fluorine chemistry. To meet the principle of green chemistry in modern synthesis, the development of new fluorination reagents as well as valid catalytic systems is crucial for mild and selective C-F bond formation. It’s undoubted that a growing number of green fluorination methodologies in aqueous media will be witnessed in the near future.

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Ecocatalyzed Suzuki cross coupling of heteroaryl compounds

spectroscopy, SYNTHESIS Comments Off

Jul 302017

Ecocatalyzed Suzuki cross coupling of heteroaryl compounds

Green Chem., 2017, Advance Article
DOI: 10.1039/C7GC01672G, Paper

Guillaume Clave, Franck Pelissier, Stephane Campidelli, Claude Grison
A bio-based EcoPd was developed for the Suzuki cross coupling of heteroaryl compounds.

Ecocatalyzed Suzuki cross coupling of heteroaryl compounds

Guillaume Clavé,^a Franck Pelissier,^a Stéphane Campidelli^b and Claude Grison*^a

*Corresponding authors

^aBio-inspired Chemistry and Ecological Innovations (ChimEco) UMR 5021 CNRS-University of Montpellier, Cap Delta, 1682 rue de la Valsière, 34790 Grabels, France
E-mail: claude.grison@cnrs.fr

^bLICSEN, NIMBE, CEA, CNRS, Université Paris-Saclay, CEA Saclay 91191 Gif-sur-Yvette Cedex, France

Abstract

A bio-based EcoPd was developed for the Suzuki cross coupling of heteroaryl compounds. Based on the ability of Eichhornia crassipes to bioconcentrate Pd in its roots, we addressed the transformation of plant-derived Pd metals to green catalysts. The methodology is based on eco-friendly procedures. It allowed the preparation of a wide range of heterocyclic biaryl and heterocyclic–heterocyclic biaryl compounds, with a low Pd catalyst loading. EcoPd was found to have the ideal microstructure to promote complex Suzuki reactions without ligands or additives. For the first time, post-reaction solution was treated by rhizofiltration. The resulting EcoPd has been reused with the same performance. This work has established the ecocatalysis concept as a powerful strategy for Pd sustainability, with the development of homogeneous catalysts that are easily recycled and reused.

2-Bromothiophene (20 g, 125 mmol), Phenyl boronic acid (16.8 g, 138 mmol), potassium carbonate (20.7 g, 150 mmol) and EcoPd1 (113 mg, 125 µmol of Pd, 13.3 mg of Pd, EcoPd1 at 11.7 wt% of Pd) were suspended into degassed glycerol (200 mL). The mixture was stirred at 120°C for 4h thanks to an oil bath under an argon atmosphere. The reaction was checked for completion by TLC (cyclohexane) and GCMS analysis after a short extraction of the organic material: 10 µL of the crude were added into a 1 mL microtube containing a mixture of water and AcOEt (800 µL, 1:1, v/v) ; the microtube was vortexed before using the organic layer to perform analysis. Deionised water (500 mL) and AcOEt (500 mL) were added into the flask and the mixture filtered through fritted glass to isolate black Pd for recycling. The organic layer was further washed by deionised water (500 mL x 3) before drying over Na2SO4. The organic layer was filtered and concentrated under vacuum. The residue was then purified by chromatography on a silica gel column (250 g) with pure cyclohexane as the mobile phase, giving the desired coupled compound as a white powder (18 g, 112.5 mmol, yield 90%) Rf = 0.7 (cyclohexane).

1H NMR (300 MHz, CDCl3):  = 7.10- 7.13 (m, 2H), 7.44-7.26 (m, 5H), 7.38-7.33 (m, 1H).

13C NMR (75.5 MHz, CDCl3):  = 123.0, 124.8, 125.9, 127.4, 128.0, 128.8, 134.4, 144.4.

MS (EI): m/z = 160 (M+ , 100%), 128 (21%), 115 (54%), 89 (17%) calcd for C10H8S: 159.99.

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Advances in indoleamine 2,3-dioxygenase 1 medicinal chemistry

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Jul 242017

Advances in indoleamine 2,3-dioxygenase 1 medicinal chemistry

Med. Chem. Commun., 2017, 8,1378-1392
DOI: 10.1039/C7MD00109F, Review Article

Open Access

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.

Alice Coletti, Francesco Antonio Greco, Daniela Dolciami, Emidio Camaioni, Roccaldo Sardella, Maria Teresa Pallotta, Claudia Volpi, Ciriana Orabona, Ursula Grohmann, Antonio Macchiarulo
Structure-function relationships of IDO1 and structure-activity relationships of inhibitors are discussed with an outlook on next generation IDO1 ligand.

From the journal:

Advances in indoleamine 2,3-dioxygenase 1 medicinal chemist

Alice Coletti,^a Francesco Antonio Greco,^a Daniela Dolciami,^a Emidio Camaioni,^a Roccaldo Sardella,^a Maria Teresa Pallotta,^b Claudia Volpi,^b Ciriana Orabona,^b Ursula Grohmann^b and Antonio Macchiarulo*^a

Author affiliations

*Corresponding authors

^aDepartment of Pharmaceutical Sciences, University of Perugia, via del Liceo 1, 06123 Perugia, Italy
E-mail: antonio.macchiarulo@unipg.it
Fax: +39 075 585 5161
Tel: +39 075 585 5160

^bDepartment of Experimental Medicine, University of Perugia, P.le Gambuli, 06132 Perugia, Italy

Abstract

Indoleamine 2,3-dioxygenase 1 (IDO1) mediates multiple immunoregulatory processes including the induction of regulatory T cell differentiation and activation, suppression of T cell immune responses and inhibition of dendritic cell function, which impair immune recognition of cancer cells and promote tumor growth. On this basis, this enzyme is widely recognized as a valuable drug target for the development of immunotherapeutic small molecules in oncology. Although medicinal chemistry has made a substantial contribution to the discovery of numerous chemical classes of potent IDO1 inhibitors in the past 20 years, only very few compounds have progressed in clinical trials. In this review, we provide an overview of the current understanding of structure–function relationships of the enzyme, and discuss structure–activity relationships of selected classes of inhibitors that have shaped the hitherto few successes of IDO1 medicinal chemistry. An outlook opinion is also given on trends in the design of next generation inhibitors of the enzyme.

Introduction Indoleamine 2,3-dioxygenases (IDOs) are heme-containing proteins that catalyze the oxidative cleavage of the indole ring of tryptophan (L-Trp, 1) to produce N-formyl kynurenine (2) in the first rate limiting step of the kynurenine pathway (Figure 1).1,2 The family includes two related enzymatic isoforms, namely IDO1 and IDO2, sharing ∼60% of sequence similarity and featuring distinct biochemical features.3,4 A third enzyme of the family is the tryptophan-2,3-dioxygenase (TDO2) which is structurally unrelated to IDO1 and IDO2 and is endowed with a more stringent substrate specificity for L-Trp.5 Although TDO2 is expressed almost exclusively in hepatocytes where it regulates L-Trp catabolism in response to the diet, IDO1 and IDO2 are widely expressed in macrophages and dendritic cells exerting immunoregulatory functions.6 These are accomplished through two major mechanisms including depletion of tryptophan and production of bioactive metabolites along the kynurenine pathway. Specifically, the first mechanism postulates that raising levels of Interferon-γ (IFN-γ) induce IDO1 expression in macrophages and dendritic cells during pathogen infection, leading to consumption of L-Trp and growth arrest of pathogens, whose diet is sensitive to this essential nutrient.7 The second mechanism grounds on production of kynurenine metabolites that bind to the aryl hydrocarbon receptor (AhR), activating signaling pathways that enhance immune tolerance.8-10 Among the three proteins, IDO1 is the most characterized enzyme and in recent years a second signal-transducing function was revealed for this protein.11,12 In particular, this signalling function relies on the presence of two immunoreceptor tyrosine-based inhibitory motifs (ITIMs) in the non-catalytic domain of IDO1.13 The immunosuppressive cytokine transforming growth factor-β (TGF-β) stimulates phosphorylation of ITIMs by Sarcoma-family (Src-family) kinases and consequent interaction of the phosphorylated enzyme with Src Homology 2 domain Phosphatase-1 (SHP-1) and Src Homology 2 domain Phosphatase-2 (SHP-2), eventually leading to long-term expression of IDO1 and immune tolerance. Conversely, in pro-inflammatory environmental conditions, increasing levels of interleukin-6 (IL-6) trigger the interaction of

phosphorylated IDO1 with suppressor of cytokine signalling 3 (SOCS3) that tags the enzyme for proteasome degradation, shortening IDO1’s half-life and promoting inflammatory response.14 The breakthrough discovery that IDO1 plays a crucial role in the maintenance of maternal immune tolerance ushered in a great deal of interest on the enzyme, by then considered a master regulatory hub of immunosuppressive pathways in pregnancy, autoimmune diseases, chronic inflammation, and cancer.15 In this framework, elevated levels of IDO1 expression found in several tumour cells were associated to the participation of the enzyme in the tumor immuno-editing process which sets up immune tolerance to tumor antigens.16,17 On this basis, academic groups and pharmaceutical companies have been engaged in the development of IDO1 inhibitors.18 Although part of these efforts has proved successful, with a large array of potent and selective inhibitors being disclosed in literature and patent applications, only few compounds have hitherto entered clinical trials (3-7, Figure 1).2,19-22 At this regard, some studies have highlighted challenges in the development of enzyme inhibitors mostly due to redox properties of the enzyme that may account for unspecific mechanism of inhibition of many compounds discovered in preclinical studies.23,24 Starting with an overview on the architecture of IDO1 and its structure-function relationships, in this article we discuss selected classes of inhibitors that have shaped advances in the medicinal chemistry of IDO1, providing outlooks on future trends in the design of next generation compounds.

Antonio Macchiarulo

PhD

Professor (Associate)

Università degli Studi di Peru… , Perugia · Department of Chemistry and Pharmaceutical Technology

Francesco Antonio Greco

PhD Student

Università degli Studi di Peru… , Perugia · Department of Chemistry and Pharmaceutical Technology

Università degli Studi di Perugia

Department of Chemistry and Pharmaceutical Technology

Perugia, Umbria, Italy

Ursula Grohmann

Università degli Studi di Peru… , Perugia · Department of Experimental Medicine and Biochemical Sciences

Ciriana Orabona

Università degli Studi di Peru… , Perugia · Department of Clinical and Experimental Medicine

Maria Teresa Pallotta

Università degli Studi di Peru… , Perugia · Department of Clinical and Experimental Medicine

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Revisiting the deoxydehydration of glycerol towards allyl alcohol under continuous-flow conditions

FLOW CHEMISTRY, flow synthesis Comments Off

Jul 172017

Revisiting the deoxydehydration of glycerol towards allyl alcohol under continuous-flow conditions

Green Chem., 2017, 19,3006-3013
DOI: 10.1039/C7GC00657H, Paper

Nelly Ntumba Tshibalonza, Jean-Christophe M. Monbaliu
Highly selective flash deoxydehydration of glycerol towards allyl alcohol under continuous-flow conditions.

From the journal:

Revisiting the deoxydehydration of glycerol towards allyl alcohol under continuous-flow conditions

Nelly Ntumba Tshibalonza^a and Jean-Christophe M. Monbaliu*^a

*Corresponding authors

^aCenter for Integrated Technology and Organic Synthesis, Department of Chemistry, University of Liège, B-4000 Liège (Sart Tilman), Belgium
E-mail: jc.monbaliu@ulg.ac.be

Abstract

The deoxydehydration (DODH) of glycerol towards allyl alcohol was revisited under continuous-flow conditions combining a microfluidic reactor setup and a unique reactive dynamic feed solution approach. Short reaction times, high yield and excellent selectivity were achieved at high temperature and moderate pressure in the presence of formic acid, triethyl orthoformate, or a combination of both. Triethyl orthoformate appeared as a superior reagent for the DODH of glycerol, with shorter reaction times, lower reaction temperatures and more robust conditions. In-line IR spectroscopy and computations provided different perspectives on the unique reactivity of glycerol O,O,O-orthoesters.

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Synthesis, characterization and anti-inflammatory evaluation of novel substituted tetrazolodiazepine derivatives

Uncategorized Comments Off

Jul 172017

SRM University

Department of Chemistry

Chennai, Tamil Nadu, India

3b R = NITRO

http://nopr.niscair.res.in/handle/123456789/42358

Dr. S. Sathishkumar

Assistant Professor in Chemistry, Kongu Engineering College, Perundurai, Erode – 638052

DR. HELEN P. KAVITHA

Dr. Helen P. Kavitha

Professor and Head of the Department
E-mail: helen.p@rmp.srmuniv.ac.in
Area: Chemistry
Affiliation: Department of Chemistry, Ramapuram Campus, SRM University

Education

Ph.D.	Organic Synthesis	Bharathidasan University, Tiruchirapalli, 2000
M.Sc.	General Chemistry	Bharathidasan University, Tiruchirapalli, 1994
B.Sc.	General Chemistry	Bharathidasan University, 1992

Other Details:

Course

Chemistry
Principles of Environmental Science

Research Interests

Organic Synthesis
Medicinal Chemistry
Crystal Growth
Molecular Docking
Nano Synthesis

Selected PublicationS

A. Santhoshkumar, Helen P. Kavitha*, R. Suresh, Hydrothermal Synthesis, Characterization and Antibacterial Activity of NiO Nanoparticles, Journal of Advanced Chemical Sciences-Article in press
R. Kavipriya, Helen P. Kavitha, B. Karthikeyan, and A. Nataraj,” Molecular structure, spectroscopic (FT-IR, FT-Raman), NBO analysis of N,N0-diphenyl-6-piperidin-1-yl-[1,3,5]-triazine-2,4-diamine, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 150 (2015) 476–487.
S. Sathishkumar, Helen P. Kavitha and S. Arulmurugan, In-silico anti-inflammatory evaluation of some novel tetrazolo and triazolodiazepine derivatives against COX-2 protien, International Journal of Advanced Chemical Science and Applications, 3(1), 2015
S. Arulmurugan and Helen P Kavitha, S. Sathishkumar and R. Arulmozhi. Review on biologically active benzimidazole, Miniriveviews in organic chemistry, 12(1), 178-195, 2015.
S. Sathishkumar and Helen P. Kavitha, Synthesis, Characterization and Anti-inflammatory Activity of Novel Triazolodiazepine Derivatives, IOSR Journal of Applied Chemistry, 8(1),47-52, 2015.
A. Silambarasan, Helen P. Kavitha, S. Ponnusamy, M. Navaneethan, Y. Hayakawa, Investigation of photocatalytic behavior of l-aspartic acid stabilized Zn(1−x)MnxS solid solutions on methylene blue Applied Catalysis A: General, 476, 22,1-8, 2014.
S. Sathish Kumar and Helen P. Kavitha, Synthesis and Biological Applications of Triazole Derivatives-A Review Mini-Reviews in Organic Chemistry, 10(1), 2013.
Helen P. Kavitha and S. Arulmurugan Synthesis, characterization and cytotoxic activity of benzoxazole, benzimidazole, imidazole and tetrazole Acta pharmaceutica 63(2), 253-264, 2013
Jasmine P. Vennila, Jhon Thiruvadigal, Helen P Kavitha, G. Chakkaravarthi and V. Manivannan, N-[2-(3,4-Dimeth-oxy¬phenyl)eth¬yl]-N-methyl-naphthalene-1-sulfonamide, Acta Crystallogr Sect E, 68(Pt 3): o890, 2012.
Jasmine P. Vennila, D. Jhon Thiruvadigal, and Helen P. Kavitha Antibacterial evaluation of some organic compounds as potential inhibitors for glucosamine-6-phospate synthase Journal of Pharmacy Research, 5(4), 1963-1966, 2012.
Helen P. Kavitha and R. Arulmozhi , Synthesis, Characterization and Anti inflammatory Activity of Some New Tetrazoles Derived from Quinazoline-4-one , International Journal of Chemistry, 1-6, 2012.
S. Arulmurugan, Helen P. Kavitha and S. Sathish Kumar. Synthesis, characterization and molecular docking studies of some new benzoxazole, benzimidazole, imidazole and tetrazole compounds as potential inhibitors for thymidylate synthase, International Journal of Science and Technology, 1, 1-11 2012.
Jasmine P. Vennila, Jhon Thiruvadigal, G. E. Theboral Sugi Kamala, Helen P Kavitha, Chakkaravarthi and V. Manivannan N-[2-(3,4-Dimeth-oxy¬phen¬yl)eth¬yl]-N-methyl¬benzene-sulfonamide” Acta Crystallogr Sect E Struct Rep Online. 68(Pt 3), o882, 2012.
Helen P Kavitha, A. Silambarasan, S. Ponnusamy, M. Navaneethan and Y, Hayakawa, Monodispersed synthesis of hierarchical wurtzite ZnS nanostructures and its functional properties” Materials Letters 81, 209-211, 2012.
Jasmine P. Vennila, Jhon Thiruvadigal, Helen P Kavitha, G. Chakkaravarthi and V. Manivannan, 2-(4-Bromophenyl)-3-(4-hydroxyphenyl)-1,3-thiazolidin-4-one” Acta Cryst., E67, o1902, 2011.
Jasmine P. Vennila, D Jhon Thiruvadigal, Helen P Kavitha, G. Chakkaravarthi and V. Manivannan 2,4-Bis(morpholin-4-yl)-6-phenoxy-1,3,5-triazine” Acta Cryst. E67, o2451, 2011.
Jasmine P. Vennila, Jhon Thiruvadigal, Helen P Kavitha, G. Chakkaravarthi and V. Manivannan, 2-Chloro-4,6-bis(piperidin-1-yl)-1,3,5-triazine” Acta Cryst. E67, o312, 2011.
Helen P. Kavitha, Samiappan Sathish kumar and Ramachandran Balajee Antimicrobial Activity and Molecular Docking Studies of Some Novel Tetrazolo Diazepine Derivatives, Journal of Pharmacy Research,4(9), 2946-2949, 2011
Helen P. Kavitha and R. Arulmozhi Study of Antimicrobial and Analgesic Activities of Novel Tetrazoles Derived from Quinazolin-4-one, Journal of Pharmacy Research , 4(12), 4696-4698, 2011.
R.Thilagavathy, Helen.P.Kavitha, R.Amrutha and Bathey.R.Venkatraman Structural parameters, charge distribution and vibrational frequency analysis using theoretical SCF methods, Elixir Comp. Chem. 40, 5514-5516, 2011.
S. Sathish Kumar, Helen P. Kavitha, S. Arulmurugan and B. R. Venkatraman, Review on Synthesis of Biologically Active Diazepam Derivatives Mini-Reviews in Organic Chemistry, 8, 1-17, 2011.
Jasmine P. Vennila, Jhon Thiruvadigal, Helen P Kavitha, B. Gunasekaran and V. Manivannan, (E)-4-{(4-Bromopenzylidene) amino} phenol, Acta Cryst, E66, O316, 2010.
Subramaniyan Arulmurugan and Helen P. Kavitha, 2-Methyl-3-{4-[-(1H-tetrazol-5-yl)ethylamino]phenyl}-3H-quinazolin-4-one”, Molbank, M695,1-5, 2010.
S. Arulmurugan, Helen P. Kavitha and B. R. Venkatraman Biological Activities of Schiff Base and its Complexes”: A Review, Rasayan Journal of Chemistry, 3(3), 385-410, 2010.
R. Thilagavathy, Helen P Kavitha and B. R. venkatraman Isolation, Characterization and Anti-Inflammatory Property of Thevetia Peruviana E-journal of Chemistry,7(4), 1584-1590, 2010.
Subramaniyan Arulmurugan, Helen P. Kavitha, B. R. Venkatraman, Synthesis, Characterization and Study of antibacterial activity of some novel tetrazole derivatives” , Orbital Elec. J. Chem, 2(3), 271-276, 2010.
With R. Thilagavathi “Synthesis of 3-{4-[4-(benzylideneamino) benzene sulfonyl]-phenyl}-2-phenylquinazoline-4(3H)-one” Molbank, M589, 2009.
With S.Sathish Kumar “Synthesis of 3-Methyl-1-Morpholin-4-ylmethyl-2,6-Diphenylpiperidin-4-One”, Molbank, M617, 2009.
With S. Sathish Kumar “6-Methyl-2,7-Diphenyl-1,4-Diazepan-5-One”, Acta Cryst., E65, (o3211), 2009.
With R. Thilagavathi “2-phenyl-4H-3,1-benzoxazian-4-one”, Acta., Cryst. (E), E65, (o127), 2009.
With Suneel Manohar Babu “4-Bromo-3-{N[2-(3,4-dimethoxy phenyl)ethyl]-N-methyl-sulfamoyl}-5-methyl benzoic acid mono hydrate”, Acta., Cryst. (E), E65, (o1568), 2009.
With Suneel Manohar Babu “2,4-Dichloro-N-phenethyl benzene Sulfonamide” , Acta., Cryst. (E), E65, (o921), 2009.
With Suneel Manohar Babu “N-(5-Bromo-2-Chlorobenzyl)-N-cyclopropylnaphthlene-2-sulfonamide”, Acta. Cryst. (E), E65, (o1098), 2009.
With Jasmine P. Vennila “4-nitrophenyl napthalene-1-sulfonate”, Acta Cryst. (E), (o1848), E64, 2008.
With R. Arulmozhi,”1- Naphthyl-9-HCarbazole-4-Sulphonate”, Acta Cryst., E66, 010208, 2008.
With T. Nithya “Antibacterial activity of Solanum Trilobatum”, Journal of Ecotoxicol.Environ. Monit., 14, (237-239), 2004.
“Synthesis and Antimicrobial activity of1-(9’Acridinyl)-5-substituted phenyl Tetrazoles”, Asian Journal of chemistry, 16, (1191-1192), 2004.
With S. V. Selva bala “Study of Hypoglysemic Activity of Solanum Xanthocarpum L. on Alloxanised Diabetic Rats”, Adv. Pharmacol Toxicol., 4, (19-24), 2003.
Helen P. Kavitha “Study of anajesic activity some novel 1-(9’Acridinyl)-5-substituted phenyl tetrazoles”, Indian Journal of Chemical Technology, 9, (361-362), 2002.
With S.Malliga, “Effect of Soaking the Wood of Emblica officinalis,on Some Water Parameters”, Journal of Swamy Bot. 15, (89-90), 1998.

Working Papers

With S. Arulmurugan, “Review on Biologically Active Benzimidazole derivatives”: Mini reviews in organic Chemistry.

Academic Experiences

Assistant Professor(S. G), SRM University, Ramapuram from Sep 2007 to Jun 2012
Lecturer, SRM University, Ramapuram from Aug 2004 to Aug 2007
Senior Lecturer, VRS College, Villupuram from Aug 2002 to May 2004
Lecturer, VRS College, Villupuram, from Aug 2000 to May 2002
Lecturer, ADM College for Women, Nagapattinam from July 94 to April 95

Other Professional Experiences

4 Scholars have been awarded Ph.D Degree
Guiding 3 Ph.D candidates
Guided 8 M. Phil and 20 M. Sc projects
Principal Investigator for a pilot project funded by SRM University (completed)
Co-investigator for a UGC major project (completed)
Reviewer for International Journals
Convenor for the National Conference on New Renaissance in Chemical Research, 2011 and 2015.
Member Board of Studies –Chemistry,SRM University.
Doctoral Committee member in Karunya University
Undertaking consultancy work in the department
Question paper setter for various universities
Convenor for many programmes conducted in the campus
Chief Superintendent for SRM University-Ramapuram campus
Member in various professional bodies such as MISTE, FICCE and CTA
Author of five books in chemistry
Executive council member in Association of Chemistry Teachers, Mumbai

Achievement and Award

Received Award and cash prize for Research from SRM University from the year 2006-15

Image result for helen p kavitha

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Catalytic carbonyl hydrosilylations via a titanocene borohydride-PMHS reagent system

spectroscopy, SYNTHESIS Comments Off

Jul 142017

Catalytic carbonyl hydrosilylations via a titanocene borohydride-PMHS reagent system

Catal. Sci. Technol., 2017, Advance Article

DOI: 10.1039/C7CY01088E, Paper

Godfred D. Fianu, Kyle C. Schipper, Robert A. Flowers II
Catalytic amounts of titanocene(III) borohydride, generated under mild conditions from commercially available titanocene dichloride, in concert with a stoichiometric hydride source is shown to effectively reduce aldehydes and ketones to their respective alcohols in aprotic media.

From the journal:

Catalytic carbonyl hydrosilylations viaa titanocene borohydride–PMHS reagent system

Godfred D. Fianu,^a Kyle C. Schipper^a and Robert A. Flowers II*^a

Author affiliations

*Corresponding authors

^aDepartment of Chemistry, Lehigh University, Bethlehem, USA
E-mail: rof2@lehigh.edu

Abstract

Reduction of a wide range of aldehydes and ketones with catalytic amounts of titanocene borohydride in concert with a stoichiometric poly(methylhydrosiloxane) (PMHS) reductant is reported. Preliminary mechanistic studies demonstrate that the reaction is mediated by a reactive titanocene(III) complex, whose oxidation state remains constant throughout the reaction.

Godfred Fianu

Lehigh University , Bethlehem · Department of Chemistry

Robert A Flowers

Danser Distinguished Faculty Chair in Chemistry and Deputy Provost for Faculty Affairs

Lehigh University , Bethlehem · Department of Chemistry

Lehigh University

Department of Chemistry

Bethlehem, United States

Phenyl methanol (2-c)
Phenyl methanol (2-c) was prepared from benzaldehyde (1-c) by the procedure outlined
in GP1. NMR analysis showed 100% conversion in 1 hour. 86% isolated yield of alcohol
product was obtained after complete workup.

1H NMR (400 MHz, CDCl3) δ 7.37 – 7.26 (m,5H), 4.59 (s, 2H), 2.99 (s, 1H).

13C NMR (101 MHz, CDCl3) δ 140.92, 128.56, 127.60, 127.07,77.52, 77.20, 76.88, 65.04.

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Control of stereoselectivity of benzylic hydroxylation catalysed by wild-type cytochrome P450BM3 using decoy molecules

SYNTHESIS, Uncategorized Comments Off

Jul 142017

Control of stereoselectivity of benzylic hydroxylation catalysed by wild-type cytochrome P450BM3 using decoy molecules

Catal. Sci. Technol., 2017, Advance Article
DOI: 10.1039/C7CY01130J, Paper

Kazuto Suzuki, Joshua Kyle Stanfield, Osami Shoji, Sota Yanagisawa, Hiroshi Sugimoto, Yoshitsugu Shiro, Yoshihito Watanabe
The benzylic hydroxylation of non-native substrates was catalysed by cytochrome P450BM3, wherein “decoy molecules” controlled the stereoselectivity of the reactions.

From the journal:

Control of stereoselectivity of benzylic hydroxylation catalysed by wild-type cytochrome P450BM3 using decoy molecules

Kazuto Suzuki,^a Joshua Kyle Stanfield,^a Osami Shoji,*^a^b Sota Yanagisawa,^a Hiroshi Sugimoto,^b^c Yoshitsugu Shiro^d and Yoshihito Watanabe*^e

Abstract

The hydroxylation of non-native substrates catalysed by wild-type P450BM3 is reported, wherein “decoy molecules”, i.e., native substrate mimics, controlled the stereoselectivity of hydroxylation reactions. We employed decoy molecules with diverse structures, resulting in either a significant improvement in enantioselectivity or clear inversion of stereoselectivity in the benzylic hydroxylation of alkylbenzenes and cycloalkylbenzenes. For example, supplementation of wild-type P450BM3 with 5-cyclohexylvaleric acid-L-phenylalanine (5CHVA-Phe) and Z-proline-L-phenylalanine yielded 53% (R) ee and 56% (S) ee for indane hydroxylation, respectively, although 16% (S) ee was still observed in the absence of any additives. Moreover, we performed a successful crystal structure analysis of 5CHVA-L-tryptophan-bound P450BM3 at 2.00 Å, which suggests that the changes in selectivity observed were caused by conformational changes in the enzyme induced by binding of the decoy molecules.

Kazuto Suzuki

suzuki.kazuto*c.mbox.nagoya-u.ac.jp

Yoshihito Watanabe

yoshi*nucc.cc.nagoya-u.ac.jp

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2,2,5,5-Tetramethyltetrahydrofuran (TMTHF): a non-polar, non-peroxide forming ether replacement for hazardous hydrocarbon solvents

SYNTHESIS Comments Off

Jul 132017

2,2,5,5-Tetramethyltetrahydrofuran (TMTHF): a non-polar, non-peroxide forming ether replacement for hazardous hydrocarbon solvents

Green Chem., 2017, Advance Article
DOI: 10.1039/C7GC01392B, Paper

Fergal Byrne, Bart Forier, Greet Bossaert, Charly Hoebers, Thomas J. Farmer, James H. Clark, Andrew J. Hunt
An inherently non-peroxide forming ether solvent, 2,2,5,5-tetramethyltetrahydrofuran (2,2,5,5-tetramethyloxolane), has been synthesized from readily available and potentially renewable feedstocks, and its solvation properties have been tested

2,2,5,5-Tetramethyltetrahydrofuran (TMTHF): a non-polar, non-peroxide forming ether replacement for hazardous hydrocarbon solvents

Fergal Byrne,^a Bart Forier,^b Greet Bossaert,^b Charly Hoebers,^b Thomas J. Farmer,^a James H. Clark^a and Andrew J. Hunt*^a

*Corresponding authors

^aGreen Chemistry Centre of Excellence, University of York, York YO10 5DD, UK
E-mail: andrew.hunt@york.ac.uk

^bNitto Belgium, NV Eikelaarstraat 22, Belgium

http://pubs.rsc.org/en/Content/ArticleLanding/2017/GC/C7GC01392B?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

Abstract

An inherently non-peroxide forming ether solvent, 2,2,5,5-tetramethyltetrahydrofuran (2,2,5,5-tetramethyloxolane), has been synthesized from readily available and potentially renewable feedstocks, and its solvation properties have been tested. Unlike traditional ethers, its absence of a proton at the alpha-position to the oxygen of the ether eliminates the potential to form hazardous peroxides. Additionally, this unusual structure leads to lower basicity compared with many traditional ethers, due to the concealment of the ethereal oxygen by four bulky methyl groups at the alpha-position. As such, this molecule exhibits similar solvent properties to common hydrocarbon solvents, particularly toluene. Its solvent properties have been proved by testing its performance in Fischer esterification, amidation and Grignard reactions. TMTHF’s differences from traditional ethers is further demonstrated by its ability to produce high molecular weight radical-initiated polymers for use as pressure-sensitive adhesives.