Conversion of indoline-2-thione and oxindole to isatin- some new observations

Department of Chemistry, Bose Institute, 93/l, A. P. C. Road, Kolkata-700 009, India E-mail: chakmanas@yahoo.co.in Fax: 91-33-23506790 Manuscript received 28 March 2003, accepted 22 August 2003 lndoline-2-thione (1) and oxindole, when treated separately with eerie ammonium nitrate adsorbed on silica gel (CAN-SiO₂) in acetonitrile, furnished isatin (2) as the sole product, whereas Montmorillonite K10 clay alone converted oxindole to isatin in a dry reaction.