Current Research Interest :
- Development of new reagent systems, synthetic transformations, and mechanistic aspects
- Gold-catalyzed C-C and C-heteroatom bond formation
- Novel methodologies for bioactive heterocycles, especially substituted furans and pyrans
Names of the group members including regular staff with designation and research fellow:
- Mr. Kanchan Mal (SRF, CSIR); e-mail: firstname.lastname@example.org
- Mr. Fazle Haque (JRF, UGC); e-mail: email@example.com
Ph.D and Postdoctoral positions are available.
CSIR/UGC NET awardees with a background in Organic Chemistry are welcome to apply via e-mail.
List of important Publications and Patents:
12. ZnI2-Catalyzed Diastereoselective [4+2] Cycloadditions of β,γ-unsaturated α-ketothioesters with Olefins By Kanchan Mal, Supriya Das, Nakul C. Maiti, Ramalingam Natarajan, and Indrajit Das, J. Org. Chem. Just Accepted, 2015.
Abstract: The potential of β,γ-unsaturated α-ketothioesters participating in hetero Diels-Alder reaction has remained unexplored. We report herein the first study of a ZnI2-catalyzed highly diastereoselective inverse electron demand hetero Diels-Alder reaction of β,γ-unsaturated α-ketothioesters with olefins to access highly substituted 3,4-dihydro-2H-pyrans. All the reactions proceed with cis-selectivity in moderate to excellent yields. Under similar reaction conditions, terminal alkynes undergo direct conjugate 1,4-addition to yield δ,ε-acetylenic α-ketothioesters. Furthermore, the utility of these cycloadducts has been
demonstrated by a NBS-MeOH mediated stereospecific efficient access to fully substituted pyran rings. The product bromoethers undergo E2 elimination with DBU, resulting in substituted 3,6-dihydro-2H-pyrans. In addition, the thioester moiety of the products has been used for further transformations, such as amidations and Fukuyama coupling reactions
11. Preparation of PNA-6-aminoglucosamine conjugates as antiviral agents By Virendra N Pandey, Jean-Luc Decout, Indrajit Das, Jérôme Désiré; U.S. Pat. Appl. Publ. (2014), US 20140371137 A1 20141218.
Abstract: The present invention relates to methods and compns. pertaining to conjugates comprising a nucleic acid oligomer conjugated to a glucosamine or a deriv. thereof which are useful for inhibiting the transcription of target nucleic acids. The conjugates of the invention exhibit advantageous bioavailability and readily penetrate cell membranes which make them useful for inhibiting translation of target mRNA in vivo. The nucleic acid oligomer hybridizes HIV TAR RNA or HCV RNA.
10. Gold(III) Chloride Catalyzed Synthesis of Chiral Substituted 3-Formyl Furans from Carbohydrates: Application to the Synthesis of 1,5-Dicarbonyl Derivative and Furo[3,2-c]pyridine By Kanchan Mal, Abhinandan Sharma, and Indrajit Das,* Chemistry - A European Journal (Full Paper), 2014, 20, 11932 – 11945.
Abstract: A gold(III)-catalyzed efficient access to substituted chiral 3-formyl furans under extremely mild conditions from suitably protected 5-(1-alkynyl)-2,3-dihydro-pyran-4-ones and H2O as a nucleophile are described. The latter can easily be synthesized from appropriately functionalized monosaccharides or commercially available glycals in a few steps following oxidation, iodination, and Sonogashira coupling sequences. Furthermore, synthesis of furo[3,2-c]pyridine from chiral 3-formyl furans has also been achieved via a TiBr4-catalyzed conversion to 1,5-dicarbonyl compound followed by treatment with NH4OAc in acidic medium.
9. PPh3.HBr-DMSO mediated expedient synthesis of γ-substituted β,γ-unsaturated α-ketomethylthioesters and α-bromo enals: Application to the synthesis of 2-methylsulfanyl-3(2H)-furanones By Kanchan Mal, Abhinandan Sharma, Prakas R. Maulik, and Indrajit Das,* Chemistry - A European Journal (Communication), 2014, 20, 662 – 667.
Abstract: An efficient chemoselective general procedure for the synthesis of γ-substituted β,γ-unsaturated α-ketomethylthioesters from α,β-unsaturated ketones has been achieved through an unprecedented PPh3.HBr-DMSO mediated oxidative bromination and Kornblum oxidation sequence. The newly developed reagent system serves admirably well for the synthesis of α-bromoenals from enals. Furthermore, AuCl3-catalyzed efficient access to 3(2H)-furanones from the above intermediates under extremely mild conditions are described.
Previous Publications and Patents:
8. A Peptide Nucleic Acid-Aminosugar Conjugate Targeting Transactivation Response Element of HIV-1 RNA Genome Shows a High Bioavailability in Human Cells and Strongly Inhibits Tat-mediated Transactivation of HIV-1 Transcription By Indrajit Das, Jérôme Désiré, Dinesh Kumar Manvar, Isabelle baussanne, Virendra N Pandey, and Jean-Luc Decout* J. Med. Chem.,2012, 5, 6021–6032.
7. 6-amino-6-deoxyglucosamine derivatives and their use as antibacterial agents By Jean-Luc Decout,* Isabelle Baussanne, Jerome Desire, Indrajit Das, and Marie-Paule Mingeot-Leclercq PCT Int. Appl. 2012, WO 2012062996 A1 20120518.
6. 6-amino-6-deoxyglucosamine derivatives and their use as antibacterial agents By Jean-Luc Decout,* Indrajit Das, Jerome Desire, Isabelle Baussanne, and Marie-Paule Mingeot-Leclercq Fr. Demande, 2012, FR 2967068 A1 20120511.
5. Unusual addition of amines to C-2 of vinyl sulfone-modified-β-d-pent-2-enofuranosyl carbohydrates: synthesis of a new class of β-anomeric 2-amino-2,3-dideoxy-d-threo-pentofuranosides By Indrajit Das, Cheravakkattu G. Suresh, Jean-Luc Décout, and Tanmaya Pathak* Carbohydr. Res., 2008, 343, 1287-1296.
4. Diastereoselective Michael Initiated Ring Closure on Vinyl Sulfone-Modified Carbohydrates: A Stereospecific and General Route to α-Substituted Cyclopropanes By Indrajit Das, Tarun K. Pal, and Tanmaya Pathak* J. Org. Chem., 2007, 72 (24), 9181–9189.
3. Diastereoselective C−C Bond Formation at C-5 of Vinyl Sulfone-Modified Hex-5-enofuranosyl Carbohydrates: Diversity-Oriented Synthesis of Branched-Chain Sugars and Beyond By Indrajit Das, Tarun K. Pal, Cheravakkattu G. Suresh, and Tanmaya Pathak* J. Org. Chem., 2007, 72 (15), 5523–5533.
2. Desulfonylation with Mg−MeOH−NiBr2: An Expedient Reagent System for the Synthesis of 2-Amino-2,3-dideoxy Furanosides By Indrajit Das and Tanmaya Pathak* Org. Lett., 2006, 8 (7), 1303–1306.
1. A Diastereoselective and General Route to 5-Amino-5-deoxysugars: Influence of C-3 Substitution on the Addition of Amines to C-5 of Vinyl Sulfone-Modified Hex-5-enofuranosyl Carbohydrates By Indrajit Das, Tanmaya Pathak*, and Cheravakkattu G. Suresh J. Org. Chem., 2005, 70 (20), 8047–8054.