反应详情

Hill et al., The Phenol Dyestuff of Liehermann as an Acridan Derivative, J. Chem. Soc. (C) 2462 (1970), describes an acridan derivative, 7-hydroxyspiro [acridine-9,1'-cyclohexa-2', 5'-diene]-2(9H), 4'-dione, that has been used as an oxidation-reduction indicator. This compound and related acridan derivatives, 4',7-dihydroxyspiro [acridine-9,1'-cyclohexane]-2(9H)-one; 7-hydroxy-2',3',5',6'-tetramethylspiro[acridine-9,1'-cyclohexa-2', 5'-diene]-2(9H), 4'-dione; 9,9-diphenyl-7-hydroxyacridin-2 (9H)-one; and 9,9-dimethyl-7-hydroxyacridin-2(9H)-one, yield blue solutions in sulfuric acid which turn red on dilution, this color being due to protonation of the free base. The neutral forms of the compounds are yellow in most solvents. A method of synthesizing these compounds is also disclosed.