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Khan MEI, Cassini TL, Petrini M, Palmieri A. Synthesis of 3,5-disubstituted isoxazoles by domino reductive Nef reaction/cyclization of β-nitroenones. Org Biomol Chem 2024; 22:3299-3303. [PMID: 38577730 DOI: 10.1039/d4ob00232f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
β-Nitroenones can be efficiently converted into 3,5-disubstituted isoxazoles by using tin(II)chloride dihydrate and ethyl acetate as a reducing agent and solvent, respectively. Products are obtained in good yields and several functional groups are tolerated thanks to the mild reaction conditions.
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Affiliation(s)
| | - Tomas Lighuen Cassini
- University of Camerino, ChIP Research Center, Via Madonna delle Carceri, 62032 Camerino, MC, Italy.
| | - Marino Petrini
- University of Camerino, ChIP Research Center, Via Madonna delle Carceri, 62032 Camerino, MC, Italy.
| | - Alessandro Palmieri
- University of Camerino, ChIP Research Center, Via Madonna delle Carceri, 62032 Camerino, MC, Italy.
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2
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Singh V, Kumar D, Mishra BK, Tiwari B. Iodobenzene-Catalyzed Synthesis of Fully Functionalized NH-Pyrazoles and Isoxazoles from α,β-Unsaturated Hydrazones and Oximes via 1,2-Aryl Shift. Org Lett 2024; 26:385-389. [PMID: 38150709 DOI: 10.1021/acs.orglett.3c04057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2023]
Abstract
An iodine(III)-catalyzed general method for the synthesis of fully functionalized NH-pyrazoles and isoxazoles from α,β-unsaturated hydrazones and oximes, respectively, via cyclization/1,2-aryl shift/aromatization/detosylation, has been developed. The reaction progresses through an anti-Baldwin 5-endo-trig cyclization. It gives direct access to an advanced intermediate for the preparation of valdecoxib and parecoxib, drugs used for COX-inhibition. In addition, a method for N-alkynylation of pyrazoles has also been developed in the presence of TIPS-EBX.
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Affiliation(s)
- Vikram Singh
- Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India
| | - Deepak Kumar
- Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India
| | - Bal Krishna Mishra
- Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India
| | - Bhoopendra Tiwari
- Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India
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3
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Gerontitis IE, Tsoungas PG, Varvounis G. Naphtho[1,8- de][1,2]Oxazin-4-ol: Precursor to 1,2,8-Trisubstituted Naphthalenes and 1-Unsubstituted Naphtho[1,2- d]isoxazole 2-Oxide: A Novel Isomerization of the N-Oxide to Nitrile Oxide en Route to Isoxazol(in)es. Molecules 2023; 29:48. [PMID: 38202629 PMCID: PMC10779812 DOI: 10.3390/molecules29010048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/12/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
Naphtho[1,8-de][1,2]oxazin-4-ol and its acyl or benzyl derivatives ring open to various 2,8-dihydroxy-1-naphthonitriles, which, through (de)protection protocols and reduction, afford the target (E)-2-hydroxy-8-methoxy-1-naphthaldehyde. This was converted to its corresponding oxime, which was oxidatively o-cyclized with phenyliodine(III) diacetate (PIDA) to 9-methoxynaphtho[1,2-d]isoxazole 2-oxide. The latter, in deuterated DMSO at room temperature, was rearranged to its isomer 2-hydroxy-8-methoxy(naphthalen-1-yl)nitrile oxide. The isomerization was detected by time-course plot 1H NMR spectroscopy and further identified from its 13C NMR and HRMS spectra. The nitrile oxide was stable in (non)deuterated DMSO for at least 18 h. A 3,4-bis(2-hydroxy-8-methoxynaphthalen-1-yl)-1,2,5-oxadiazole 2-oxide, as a dimerization product or an isocyanate as a rearrangement isomer, was ruled out, the former by its HRMS spectrum and the latter by its 1,3-dipolar cycloaddition reactions to substituted isoxazoles.
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Affiliation(s)
- Ioannis E. Gerontitis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, 451 10 Ioannina, Greece;
| | - Petros G. Tsoungas
- Department of Biochemistry, Hellenic Pasteur Institute, 127 Vas. Sofias Ave., 115 21 Athens, Greece;
| | - George Varvounis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, 451 10 Ioannina, Greece;
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4
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Singh V, Mishra BK, Kumar D, Tiwari B. Construction of Highly Functionalized C4-Oxyacylated and Aminated Pyrazolines. Org Lett 2023; 25:7089-7094. [PMID: 37748130 DOI: 10.1021/acs.orglett.3c02366] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Pyrazolines and pyrazolones are prevalent cores in drugs and bioactive molecules. Functionalizing them with heteroatoms on the ring improves or expands their clinical efficacy. However, a general method to selectively heterofunctionalize them at C4 and C5 is still elusive. Herein, we have demonstrated an iodine(III)-mediated construction of C4-heterofunctionalized pyrazolines from α,β-unsaturated hydrazones. The oxyacylated and aminated products, bearing a tertiary as well as a secondary stereocenter, were obtained via aza-Michael, followed by a C-O/C-N bond formation. A deprotection/oxidation sequence produced pyrazolones in a quantitative yield.
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Affiliation(s)
- Vikram Singh
- Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India
| | - Bal Krishna Mishra
- Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India
| | - Deepak Kumar
- Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India
| | - Bhoopendra Tiwari
- Department of Biological and Synthetic Chemistry, Centre of Biomedical Research, SGPGIMS-Campus, Raebareli Road, Lucknow 226014, India
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5
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Panigrahi P, Ghosh S, Khandelia T, Mandal R, Patel BK. Isoxazole as a nitrile synthon: en routes to the ortho-alkenylated isoxazole and benzonitrile with allyl sulfone catalyzed by Ru(II). Chem Commun (Camb) 2023; 59:10536-10539. [PMID: 37565340 DOI: 10.1039/d3cc02996d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
A Ru(II) catalyzed regioselective Heck-type C-H olefination of isoxazole with unactivated allyl phenyl sulfone is revealed. The solvent DCM offers dual sp2-sp2 C-H activation via an N-directed strategy, leading to ortho-olefinated isoxazoles with exclusive E-selectivity. On the other hand, in DCE solvent, isoxazole serves as the nitrile synthon and leads to o-olefinated benzonitrile. At a higher temperature (110 °C) in DCE, after the ortho-olefination Ru(II) mediated cleavage of isoxazoles delivered the nitrile functionality.
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Affiliation(s)
- Pritishree Panigrahi
- Department of Chemistry, Indian Institute of Technology Guwahati, 781039, Assam, India.
| | - Subhendu Ghosh
- Department of Chemistry, Indian Institute of Technology Guwahati, 781039, Assam, India.
| | - Tamanna Khandelia
- Department of Chemistry, Indian Institute of Technology Guwahati, 781039, Assam, India.
| | - Raju Mandal
- Department of Chemistry, Indian Institute of Technology Guwahati, 781039, Assam, India.
| | - Bhisma K Patel
- Department of Chemistry, Indian Institute of Technology Guwahati, 781039, Assam, India.
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6
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Jiaping J, Woldegiorgis AG, Lin X. Chiral spirocyclic phosphoric acid-catalyzed enantioselective synthesis of heterotriarylmethanes bearing an amino acid moiety. RSC Adv 2023; 13:18964-18973. [PMID: 37362600 PMCID: PMC10285616 DOI: 10.1039/d3ra03480a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 06/17/2023] [Indexed: 06/28/2023] Open
Abstract
We present herein an enantioselective protocol for the chiral phosphoric acid-catalyzed addition of 3-arylisoxazol-5-amines to highly reactive 3-methide-3H-pyrroles to provide a diverse range of heterotriarylmethanes bearing an amino acid moiety in good yields (up to 97%) and high enantioselectivities (up to 93% ee) under mild conditions. The chiral spirocyclic phosphoric acid is crucial in converting the initial 1H-pyrrol-3-yl carbinols into reactive 3-methide-3H-pyrroles and obtaining the good enantiocontrol, thereby facilitating the desired enantioselective transformation.
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Affiliation(s)
- Jin Jiaping
- Center of Chemistry for Frontier Technologies, Department of Chemistry, Zhejiang University Hangzhou 310058 China
| | | | - Xufeng Lin
- Center of Chemistry for Frontier Technologies, Department of Chemistry, Zhejiang University Hangzhou 310058 China
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7
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Pattanayak P, Chatterjee T. Synthesis of (4-Trifluoromethyl)isoxazoles through a Tandem Trifluoromethyloximation/Cyclization/Elimination Reaction of α,β-Unsaturated Carbonyls. J Org Chem 2023; 88:5420-5430. [PMID: 36913616 DOI: 10.1021/acs.joc.2c03053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/15/2023]
Abstract
We disclose a metal-free, cascade regio- and stereoselective trifluormethyloximation, cyclization, and elimination strategy with readily available α,β-unsaturated carbonyl compounds to access a wide variety of pharmaceutically potential heteroaromatics, i.e., 4-(trifluoromethyl)isoxazoles including a trifluoromethyl analogue of an anticancer agent. The transformation requires only a couple of commercially available and cheap reagents i.e., CF3SO2Na as the trifluoromethyl source, and tBuONO as an oxidant as well as a source of N and O. Notably, 5-alkenyl-4-(trifluoromethyl)isoxazoles were further synthetically diversified to a new class of biheteroaryls, i.e., 5-(3-pyrrolyl)-4-(trifluoromethyl)isoxazoles. Mechanistic studies revealed a radical pathway for the reaction.
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Affiliation(s)
- Paramita Pattanayak
- Department of Chemistry, Birla Institute of Technology and Science, Pilani (BITS Pilani), Hyderabad Campus, Jawahar Nagar, Hyderabad 500078, Telangana, India
| | - Tanmay Chatterjee
- Department of Chemistry, Birla Institute of Technology and Science, Pilani (BITS Pilani), Hyderabad Campus, Jawahar Nagar, Hyderabad 500078, Telangana, India
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8
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Linden M, Hofmann S, Herman A, Ehler N, Bär RM, Waldvogel SR. Electrochemical Synthesis of Pyrazolines and Pyrazoles via [3+2] Dipolar Cycloaddition. Angew Chem Int Ed Engl 2023; 62:e202214820. [PMID: 36478106 DOI: 10.1002/anie.202214820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 12/06/2022] [Accepted: 12/06/2022] [Indexed: 12/12/2022]
Abstract
Pyrazolines and pyrazoles are common and important motifs of pharmaceutical agents and agrochemicals. Herein, the first electrochemical approach for their direct synthesis from easily accessible hydrazones and dipolarophiles up to decagram scale is presented. The application of a biphasic system (aqueous/organic) even allows for the conversion of highly sensitive alkenes, wherein inexpensive sodium iodide is employed in a dual role as supporting electrolyte and mediator. In addition, mechanistic insight into the reaction is given by the isolation of key step intermediates. The relevance of the presented reaction is underlined by the synthesis of commercial herbicide safener mefenpyr-diethyl in good yields.
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Affiliation(s)
- Martin Linden
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Silja Hofmann
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Antonia Herman
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Nicole Ehler
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
| | - Robin M Bär
- Research & Development, Crop Science, Bayer AG, Alfred-Nobel-Str. 50, 40789, Monheim am Rhein, Germany
| | - Siegfried R Waldvogel
- Department of Chemistry, Johannes Gutenberg University Mainz, Duesbergweg 10-14, 55128, Mainz, Germany
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9
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Synthetic utility of styrenes in the construction of diverse heterocycles via annulation/cycloaddition. Tetrahedron 2023. [DOI: 10.1016/j.tet.2023.133270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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10
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Saleh EAM, Kotian SY, Al Dawsari AM, Hassan I, Husain K, Abishad PC, Byrappa K, Sharabi RSSAL, Rai KML. Synthesis, Antioxidant, and Antibacterial Activities of Two Novel Series of 3,5-Disubstituted Isoxazole Ether-Linked Isoxazolines and 3,5-Disubstituted Pyrazole Ether-Linked Isoxazolines Mediated by Chloramine-T. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2022. [DOI: 10.1134/s1068162022050181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Bai YJ, Cheng ML, Zheng XH, Zhang SY, Wang PA. Chiral Cyclopropenimine-catalyzed Asymmetric Michael Addition of Bulky Glycine Imine to α,β-Unsaturated Isoxazoles. Chem Asian J 2022; 17:e202200131. [PMID: 35415949 DOI: 10.1002/asia.202200131] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/26/2022] [Indexed: 11/11/2022]
Abstract
A highly efficient asymmetric Michael addition of bulky glycine imine to α,β-unsaturated isoxazoles has been achieved by using 5 mol% of chiral cyclopropenimine as a chiral organo-superbase catalyst under mild conditions. Michael adducts were obtained in excellent yields (up to 97%) and stereoselectivities (up to>99 : 1 dr and 98% ee). A significant solvent effect was found in these chiral organosuperbase catalyzed asymmetric Michael reactions. Gram-scale preparation of Michael adducts and their transformations are realized to provide corresponding products without loss of stereoselectivities. The configurations of Michael adduct was determined by single-crystal X-ray diffraction analysis.
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Affiliation(s)
- Yu-Jun Bai
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, The College of Life Sciences, Northwest University, Xi'an, 710069, P. R. China) E-mails.,Department of Medicinal Chemistry and Pharmaceutical Analysis, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, P. R. China
| | - Mei-Ling Cheng
- Department of Medicinal Chemistry and Pharmaceutical Analysis, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, P. R. China
| | - Xiao-Hui Zheng
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, The College of Life Sciences, Northwest University, Xi'an, 710069, P. R. China) E-mails
| | - Sheng-Yong Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, The College of Life Sciences, Northwest University, Xi'an, 710069, P. R. China) E-mails.,Department of Medicinal Chemistry and Pharmaceutical Analysis, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, P. R. China
| | - Ping-An Wang
- Department of Medicinal Chemistry and Pharmaceutical Analysis, School of Pharmacy, Fourth Military Medical University, Xi'an, 710032, P. R. China
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12
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Nikitina EV, Çelikesir ST, Akkurt M, Petkevich SK, Akishina EA, Khrustalev VN, Mlowe S. Crystal structure and Hirshfeld surface analysis of 5-(5-phenyl-1,2-oxazol-3-yl)-1,3,4-thiadiazol-2-amine. Acta Crystallogr E Crystallogr Commun 2022; 78:453-457. [PMID: 35492272 PMCID: PMC8983972 DOI: 10.1107/s2056989022003450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 03/27/2022] [Indexed: 11/23/2022]
Abstract
In the crystal, the molecules are linked by N—H⋯N and C—H⋯N hydrogen bonds, forming double layers parallel to the (001) plane. The layers are connected by van der Waals interactions, generating a three-dimensional supramolecular structure. The title compound, C11H8N4OS, crystallizes with two independent molecules in the asymmetric unit. In the crystal, the N—H⋯N and C—H⋯N hydrogen bonds connect the molecules, generating double layers parallel to the (001) plane. The layers are joined by C—H⋯π interactions to form a three-dimensional supramolecular structure.
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13
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Kotipalli R, Nagireddy A, Reddy MS. Palladium-catalyzed cyclizative cross coupling of ynone oximes with 2-haloaryl N-acrylamides for isoxazolyl indoline bis-heterocycles. Org Biomol Chem 2022; 20:2609-2614. [PMID: 35298580 DOI: 10.1039/d2ob00065b] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Metal-catalyzed cyclizative cross-coupling reactions have attracted enormous attention due to their unique cascade nature. We demonstrated, herein, a dual-cyclizative coupling of ynone oxime ethers with acrylamides for the synthesis of methylene-linked isoxazolyl 2-oxindoles. The cascade was triggered by a palladium(II)-catalyzed ynone oxime ether cyclization, which underwent a Heck-type coupling intercepted by an aryl iodide insertion. Control experiments were carried out to understand the mechanism.
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Affiliation(s)
- Ramesh Kotipalli
- Department of OSPC, CSIR-Indian Institute of Chemical Technology, Habsiguda, Hyderabad 500007, India.,Academy of Scientific and Innovative Research, Ghaziabad 201002, India.
| | - Attunuri Nagireddy
- Department of OSPC, CSIR-Indian Institute of Chemical Technology, Habsiguda, Hyderabad 500007, India.,Academy of Scientific and Innovative Research, Ghaziabad 201002, India.
| | - Maddi Sridhar Reddy
- Department of OSPC, CSIR-Indian Institute of Chemical Technology, Habsiguda, Hyderabad 500007, India.,Academy of Scientific and Innovative Research, Ghaziabad 201002, India.
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