Usha Ranjan Ghatak obtained his PhD degree (1957) from the University of Calcutta. His areas of specialization were synthetic organic chemistry and stereochemistry. He was Director, Professor and Head, Department of Organic Chemistry, Indian Association for the Cultivation of Science, Kolkata. After superannuation, Ghatak was INSA Senior Scientist at Indian Institute of Chemical Biology, Kolkata.
Academic and Research Achievements: Ghatak made significant contributions to stereo-controlled synthesis of polycarbocyclic diterpenoids, and bridged-ring compounds related to bioactive natural products. He developed regio- and stereo-specific intramolecular alkylation rearrangements through diazoketones, and new annulation reactions involving cationic and radical processes, leading to the synthesis of complex carbocyclic systems.
At the early stage of his research career, Ghatak and his co-workers achieved total synthesis of some resin acids of profound contemporary interest such as podocarpic acid, desisopropyl dehydroabietic acid and 5-epi-deoxypodocarpic acid. These studies clarified the stereochemical uncertainties that existed in the literature and paved the way for entry into other related compounds. Synthesis of the plant hormones, gibberellins possessing a bridged-tetracyclic carbon skeleton, was a challenging problem from structural and stereochemical points. Bond reorganization of strained ring systems was the most fascinating aspect in Ghatak’s approach to structurally complex natural products. A large number of synthetic methodologies for the carbon-carbon bond formations and reorganizations have been developed by Ghatak and his co-worker.
Other Contributions: Dr Ghatak was a member of Editorial Boards of Indian Journal of Chemistry (Sec B), Proceedings of Indian Academy of Sciences (Chem Sci) and Proceedings of Indian National Science Academy. He served as Chairman and Member of Research Councils of several CSIR laboratories. He was also a Member of INSA Council (1994-96).
Awards and Honours: Dr Ghatak was a recipient of SS Bhatnagar Prize (1974). He was honoured with Professor K Venkataraman Endowment Lecture (1982), Acharya PC Ray Memorial Lecture (1985), Professor NV Subba Rao Memorial Lecture (1986), Dr RC Shah Memorial Lecture (1986), TR Sheshadri Memorial Lecture (1987) and Baba Kartar Singh Memorial Lecture (1990) and S Swaminathan Sixtieth Birthday Commemoration Lecture of INSA (1994). He was a Fellow of Indian Academy of Sciences, Bangalore, an Associate Member of Royal Society of Chemistry (London) and Chemical Society (London).