STUDIES ON 2-MERCAPTO COUMARINOXAZOLE SYSTEMS: SYNTHESIS OF NOVEL TYPES OF 2-MERCAPTO-9-METHYL-7H-PYRANO-(3,2-e)BENZOXAZOLE-7-ONE DERIVATIVES—PART III

Abstract 5-Amino-6-hydroxy-4-methylcoumarin (I) when treated with carbon disulphide in alkaline medium to furnish the novel and hitherto unknown 2-mercapto-9-methyl-7H-pyrano(3,2-e)benzoxazole-7-one (IIa). Treatment of IIa with alkyl halides and acid halides gives the corresponding thioethers (IIb-i) and thioesters (IIj-k) respectively. Oxidation of IIb, IIc, IId, IIf, IIh with hydrogenperoxide gives the corresponding sulfones (IIIa-e). These are characterised by elemental analysis, IR, PMR and mass spectral data.