• Kuppuswamy Nagarajan

      Articles written in Journal of Chemical Sciences

    • Creative research in the chemical industry – Four decades in retrospect

      Kuppuswamy Nagarajan

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      My professional research career spanning more than four decades has been largely devoted to synthetic medicinal chemistry (Ciba, Bombay — now Mumbai — 21 years) followed by an equal number of years in process development of drugs, crop protection chemicals (Searle, Bombay) and drugs and speciality chemicals (Recon and Hikal, Bangalore). These efforts have involved several collaborators including many from other institutions and offered multitudinous challenges calling for continuous creativity in industrial setups. I was fortunate to have had a conducive environment to be able to respond to these challenges. I attempt to offer the readers in the ensuing pages a flavour of the excitement that has marked these years

    • A new synthesis of Entacapone and report on related studies

      Attimogae Shivamurthy Harisha Suresh Parameshwar Nayak Pavan M S Shridhara K Sundarraja Rao K Rajendra K Koteppa Pari Sivaramkrishnan H Guru Row T N Kuppuswamy Nagarajan

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      A new synthesis of the catechol-𝑂-methyltransferase (COMT) inhibitor, entacapone (E-isomer) has been achieved under mild conditions by amine-mediated demethylation of the precursor 2-Cyano-3-(3-hydroxy-4-methoxy-5-nitrophenyl) prop-2-eneamide, wherein the methoxyl group adjacent to a nitro group gets demethylated under nucleophilic attack. Similar demethylation was achieved on ethyl 2-cyano-3-(3,4-dimethoxy-5-nitrophenyl) prop-2-enoate, 2-cyano-3-(3,4-dimethoxy-5-nitrophenyl)-N,N-diethylprop-2-enamide, ethyl 2-cyano-3-(3-hydroxy-4-methoxy-5-nitrophenyl) prop-2-enoate and ethyl 2-cyano-3-(4-methoxy-3-nitrophenyl) prop-2-enoate. The scope of demethylation has been studied. Analogues of ethyl 2-cyano-3-(3,4-dimethoxy-5-nitrophenyl) prop-2-enoate wherein a methoxyl group is not adjacent to a NO2 group are unaffected and phenolic derivatives yield the amine salts. Entacapone has been converted to salts with organic bases. The crystal structure of the isomer of entacapone (Z-isomer), a significant human metabolite of E-isomer has been established. NMR methods for deriving E and Z geometry and other similar molecules have been successfully established, mainly by studying the proton coupled $_{}^{13}$C spectra. Preliminary studies reveal in vitro activity for some compounds against tuberculosis (TB) and dengue.

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