Halochrome Moleküle 9. Mitteilung[1]. Substituierte 6,11-Dihydrospiro[[1]benzopyrano[4,3-b]indol-6,9′-9′H-xanthen]-2′,6′-diamine und ihre Aza-analogen: Neue Chromogene für schwarze Farbbilder

Halochromic Molecules. Substituted 6,11-Dihydrospiro1]benzopyrano4,3-b]indol-6,9′-9′H-xanthene]-2′,6′-diamines and Their Aza Analogues: New Chromogenes for Black Images . We have synthesized a series of substituted 6,11-dihydrospiro1]benzopyrano4,3-b]indo1-6,9′-9′H-xanthene]-2′,6′-diamines and their respective aza analogues. These compounds develop a black colour in acidic media. The assumed structures of the analytically pure starting and final products are consistant with the fragmentations in the MS and are also supported by FT ¹H-NMR. The UV/VIS spectra in buffered MeOH/H₂O solutions were measured. From the ?_pH* curves, we determined the pK* values. The title compounds can be used in so-called pressure-sensitive copying systems.