| Summary: | The ketoacid, 2-(4-diethylamino-2-hydroxybenzoyl)benzoic acid, prepared from N,N-diethyl-m-aminophenol and phthalic anhydride, was reacted with various substituted 3-[6-methoxybenzothiazol-2-yl]-4(3H)-quinazolinones in the presence of a dehydration condensing agent to afford novel spiro[isobenzofuran-1(3H),9’-xanthene]-3-ones. The benzothiazolyl quinazolinones were synthesized by reacting 2-amino-6-methoxybenzothiazole with various substituted benzoxazinones. All compounds were characterized by melting point determination, elemental analysis, infra- red spectroscopy, NMR-spectroscopy and UV-visible sprectroscopy. All the fluoran compounds are colourless or nearly colourless and produce colour in the presence of acidic media.
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