Sambasivarao Kotha

    Professor

    Department of Chemistry

    Indian Institute of Technology Bombay

    Powai, Mumbai 400076

    Ph:   022-2576 7160

    Fax:  022-2572 7152

    Email: srk@chem.iitb.ac.in

    Group Webpage

Academic Background

B.Sc. Andhra Loyola College-Vijayawada, Nagarjuna University M.Sc.  University of Hyderabad-Hyderabad

Ph.D.  University of Hyderabad-Hyderabad

Professional Experience

Professor 2001 Feb-

Associate Professor 1997 July -2001 Feb IIT-Bombay

Assistant Professor 1994 -1997 July  IIT-Bombay

Research Chemist II 1992-1993,  Hoechst Celanese,TX

Visiting Scientist 1990-1991,  Cornell Uni, NY

Research Associate 1987-1989,  Univ. of  Wisconsin,WI

Research Associate 1986-1987,  UMIST, Manchester, UK

Post Doctoral Fellow 1984-1986, Univ. of Hyderabad

 

Research Interests

New Synthetic methods, Unusual amino acids, Suzuki coupling reaction, Metathesis,

Peptide modifications, Nanotechnology, Theoretically interesting molecules.

 

   Our group at IIT-B has been engaged in developing new and novel synthetic methods for the preparation of unusual a-amino acids (AAAs) and polycyclic compounds. Synthetic AAAs have been found to play a significant role in the interface of chemistry and biology. Our approach to these AAAs is based on the development of new building blocks embodying AAA moiety, which are useful in the preparation of diverse AAAs of higher order ring systems.

 

    Recently, we have demonstrated that solid-liquid phase-transfer catalysis is remarkably effective in the preparation of constrained AAAs with highly electron deficient and electron-rich side chains using ethyl isocynaoacetate as a glycine equivalent. This approach has been successfully applied for the synthesis of several indane-based AAAs, which are inaccessible, by the other known methods. This methodology is also extended to indane-based constrained a-amino acid derivatives containing crown-ether side chain for the first time. Parallel to this methodology, we have shown that 2+2+2 and 4+2 cycloaddition reactions are useful for the synthesis of constrained analogues of phenylalanine. Using 2+2+2 cycloaddition reaction we have prepared the indane based amino acids. Our cycloaddition methodology demonstrates the feasibility of introducing diverse functionalities by judicious choice of the reacting partners. Post-translational peptide modification was also established via 2+2+2 cycloaddition reaction. In connection with various unusual AAA derivatives we have utilized ring-closing metathesis, enyne metathesis, and cross metathesis reactions as key steps.

 

    In connection with our interest to prepare exotic non-natural products such as dodecahedron, our group has developed a simple and straight forward three-step methodology for cyclopentane annulation using inexpensive reagents. By this method, various hexaquinane ring systems were prepared from the readily available bicyclo(3.3.0)octane dione derivatives. A new method for spiro-cyclopentane annulation was demonstrated using ring-closing metathesis reaction as a key step. Fragmentation methodology was utilized to allylate some polycyclic diketones where ionic conditions are inappropriate. We have prepared various star-shaped thiophene derivatives using tetrachlorosilane mediated trimerization and Suzuki coupling reactions as key steps. This methodology has been  extended to various dendrimer-type molecules

 

Represented Publications

  • S. Kotha, K. Mandal A retrospective on the design and synthesis of novel molecules through a strategic consideration of metathesis and Suzuki-Miyaura cross-coupling reaction.Chem. Asian. J. 354, 4, 2009.



  • S. Kotha,A. Deb, K. Lahiri, E. Manivannan Recent synthetic approaches to spirocyclics.Synthesis 165, 2009.



  • S. Kotha, M. Mishram, A. Tiwari Advanced approach to polycyclics by a synergistic combination of enyne metathesis and Diels-Alder reaction Chem. Soc. Rev. 2065, 38, 2009



  • S. Kotha, P. Khedkhar Differential reactivity pattern of hybrid o-quinodimethane precursors: Strategic expansion to annulated benzocycloalkanes via Rongalite J. Org. Chem. 5667, 74, 2009



  • S. Kotha, S. Misra, S. Halder Benzannulation.Tetrahedron 10775, 64, 2008



  • S Kotha, K. Lahiri Design and synthesis of diverse polycyclic compounds via catalytic metathesis.Synlett 2767, 2007



  • S. Kotha, V. R. Shah, K. Mandal Formation of Arenes via Diallylarenes: Strategic Utilization of Suzuki-Miyaura Cross-Coupling, Claisen Rearrangement and Ring-Closing Metathesis.Adv. Synth. Cat. 1159, 2007



  • S Kotha, K. Mandal, A. Tiwari, S. M. Mobin Diversity-oriented approach to biologically relevant molecular frameworks starting with -naphthol using Claisen rearrgement and olefin metathesis as key steps.Chem. Eur. J. 8024, 2006



  • S. Kotha S. Banerjee, M. P. Patil, R. B. Sunoj Retro Diels-Alder reaction under mild conditions: experimental and theoretical studies.Org. Biomol. Chem. 1854, 2006.



  • S. Kotha, E. Brahmachary, K. Lahiri Transition metal-catalyzed [2+2+2] cycloaddition and application in organic synthesis.Eur. J. Org. Chem. 4741, 2005



  • S. Kotha, S. Banerjee, K. Mandal Oxidative dehydrogenation and the aromatization of polycycles using o-iodoxybenzoic acid (IBX).Synlett 2043, 2004



  • S. Kotha The building block approach to unusual -amino acid derivatives and peptides.Acc. Chem. Res. 342, 2003



  • S. Kotha, K. Lahiri, D. Kasinath Recent applications of Suzuki-Miyaura cross-coupling reaction in organic synthesis.Tetrahedron 58, 9633, 2002



  • S. Kotha, N. Sreenivasachary Catalytic metathesis in organic synthesis.Indian J. Chem. 40B, 763, 2001



  • S. Kotha, S. Halder, E. Brahmachary, T. Ganesh Synthesis of unusual a-amino acid derivatives via cross enyne metathesis reaction.Synlett 853, 2000



  • S. Kotha, N. Sreenivasachary A novel synthetic approach to 1, 2, 3, 4-tetrahydroisoquinoline-3-carboxylic acid (Tic) derivatives via enyne-metathesis and the Diels-Alder approach.Chem. Commun. 503, 2000



  • S. Kotha, E. Brahmachary Synthesis of indane-based unusual-amino acid derivatives under phase-transfer catalysis conditions.J. Org. Chem. 65, 1359, 2000



  • S. Kotha, K. Chakraborty, E. Brahmachary A general and simple method for the synthesis of star-shaped thiophene derivatives.Synlett 1621, 1999



  • S. Kotha, N. Sreenivasachary, E. Brahmachary Synthesis of constrained a-amino acid derivatives via enyne-metathesis reaction.Tetrahedron Lett. 39, 2805, 1998



  • S. Kotha, E. Brahmachary Synthesis of unusual -amino acids via a [2+2+2] cycloaddition strategy.Tetrahedron Lett. 38, 3561, 1997