Hyderabad|India|June'2012: For the first time king size pre-transition state of asymmetric supramolecular reaction was discovered and analyzed by Dr. D. B. Ramachary and his team from Catalysis Laboratory, School of Chemistry, University of Hyderabad. The findings have been published in the prestigious international chemistry journal, Chemistry - A European Journal, published by Wiley-VCH on behalf of ChemPubSoc Europe.

Entire living and non-living systems existed in this world are generated through variety of chemical and biological reactions on the simple atoms/molecules as starting materials catalyzed by small amino acids to big enzymes.

To understand the process of chemical and biological reactions in living and non-living systems, first we need to understand the catalytic power of small to big molecules in a variety of chemical and biological reactions.

That is the reason for many chemists/biologists to study and practice the catalysis as an important area in chemical and biological sciences.

For the last few decades, many chemists/biologists are working to reveal the reaction pathways in a clearer manner especially on the “transition state” of the reactions.

In 1999, Professor Ahmed H. Zewail from California Institute of Technology, Pasadena, USA got Nobel Prize in Chemistry for his studies of the transition states of fundamental chemical reactions using ultra-short laser flashes, on the time scale on which the reactions actually occur (femtosecond spectroscopy). Professor Zewail's contributions have brought about a revolution in chemistry and adjacent sciences, since this type of investigation allows us to understand and predict important reactions.

But this femtosecond spectroscopy may not be suitable to study the transition states of sensitive asymmetric reactions due to the use of high energy ultra-short laser flashes.

Alternatively Dr. D. B. Ramachary from School of Chemistry, University of Hyderabad emphasizes the need for development of different smooth ways of studying pre- or post-transition states of complex asymmetric chemical reactions using electrospray ionization with high resolution mass spectrometry (ESI-HRMS) technique that have an influence on the variety of chemical/biological reactions.

“Highly reactive pre-transition state of the chemical reactions can be made much more stable to monitor with ESI-HRMS by designing the processes in such a way that multiple weak hydrogen bond and covalent bond interactions operate synergistically between substrates and catalysts in the course of reaction,” he said.

Dr. D. B. Ramachary, Ms. R. Sakthidevi and Ms. K. S. Shruthi for the first time discovered the utilization of large size supramolecular rings in the pre-transition state of enamine-based Michael reactions for the high asymmetric induction. They have got a strong support for the hypothesis which involves a stable pre-transition state supramolecular assembly through careful investigation of the Michael reaction of cyclohexanone and 2-(2-nitrovinyl)phenol under the d-proline/quinine-NH-thiourea-catalysis using electrospray ionization with high resolution mass spectrometry (ESI-HRMS) technique, which enabled them to identify all critical proposed catalytic intermediates (see Scheme).

Enantiomerically pure, drug-like hexahydroxanthenes having three contiguous stereocenters were synthesized through supramolecular-catalysis by D-proline and quinine-NH-thiourea followed by reductive etherification from simple precursors under the mild conditions (see Scheme).

Dr Ramachary said he derived the inspiration to develop this novel chemical philosophy/technology from the sociological chemistry, where people work together to sustain their identity and success.

“Similarly, design of synergetic one-pot combination of multiple-hydrogen bond interactions and multiple-covalent bonds between substrates and catalysts will be victorious over many problems in organic and pharmaceutical chemistry,” he said.

-June'' 2012