SOLVENT-INDUCED SYNTHESIS OF SPIRO [INDOLE-PYRAN] SYSTEM USING CONDENSATION-REACTIONS

Reaction of indole-2,3-dione with 4-hydroxy-2H-1-benzopyran-2-one 2 ha s been studied under different media and a single one-step synthesis o f a never spiro[indole-pyran] system is achieved. piro[indole-3,7'-[6H ,7H,8H]pyrano[3,2-c;5,6-c']di[ 1]benzopyran]-2(3H),6',8'-trione 4a, it s N-methyl 4b and 5-fluoro 4c analogues have been synthesised by the r eaction of indole-2,3-dione la, its N-methyl 1b and 5-fluoro 1c deriva tives respectively with 2 under different reaction conditions. All the synthetic spiro compounds 4a-c have been fully characterized on the b asis of their IR, H-1 and C-13 NMR and mass spectral data.