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      https://www.ias.ac.in/article/fulltext/jcsc/104/01/0027-0042

    • Keywords

       

      CGI 14600; hypoglycemic; 13C and1H NMR spectra; X-ray crystal structure

    • Abstract

       

      IR, UV, NMR and mass spectral data for the title compounds are discussed. The EI mass spectra of4. and the analogues59 and1115 display major (M-Cn2H3O2)+ fragment ions that correspond to the loss of a structural element not present in the parent molecules. These (M-59)+ ions have no equivalent in the model compound l-phenyl-2,6,6-trimethyl-4-oxo-4, 5,6,7-tetrahydroindole (27). The unusual fragmentation is thought to be initiated by α-cleavage within the alicyclic 1,3-diketone moiety (ring C) under concomitant formation of a benzylic radical site. Reclosure of this ‘open’ intermediate to a lactone-type molecular ion provides two O-atoms in the proximity required for an ejection of a CH2COOH radical as the neutral species in question. The1H NMR spectra of4 and its methyl ether16 reveal restricted rotation of substituents at positions 1 and 3 of the pyrrole ring, the eight methylene protons becoming fully anisochronous at 500 MHz. X-ray studies on single crystals of8 confirmed its structure.

    • Author Affiliations

       

      K Nagarajan1 2 S J Shenoy2 D R Müller W J Richterc3 L Kozerski4 V Pattabhi5

      1. Hindustan CIBA-GEIGY Research Centre, Bombay - 400063, India
      2. Searle R & D Centre, 25, MIDC Land, Thane-Belapur Road, Thane - 400601, India
      3. Research Services Physics, CIBA-GEIGY AG, Basel - CH 4002, Switzerland
      4. Institute of Organic Chemistry, Polish Academy of Sciences, Warszawa - 00-961, Poland
      5. Department of Crystallography and Biophysics, University of Madras, Guindy, Madras - 600025, India
    • Dates

       
  • Journal of Chemical Sciences | News

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