Untersuchungen in der Benztropylium‐Reihe IX. Die Absorptions‐Spektren der 2‐Alkyl‐4,5‐benztropone, 2,7‐Dialkyl‐4,5‐benztropone und 5,7‐Dialkyl‐2,3‐benztropone

The preparation and the absorption spectra of 2‐alkyl‐ and 2,7‐dialkyl‐4,5‐benztropones (with alkyl = methyl, ethyl, propyl, hexyl, iso‐propyl and tert.‐butyl), and of 5,7‐dialkyl‐2,3‐benztropones (with alkyl = methyl and ethyl) are described.