Dyes Derived from Substituted Phthalic Acids. Part V. 3,6-Endoxo­hexahydrophthalic Acid. Effect of Completely Saturating and also of Introducing an Oxygen Bridge in the Phthalic Acid Portion of Phthalein Dyes

3,6-Endoxohexahydrophthalic acid, in the form of its anhydride. has been condensed with a number of aromatic hydroxy (phenols) and hydroxyamino (m-diethylaminophenol) compounds. The phthalein and rhodamine types of compounds hare been studied analytically and spectrophotometrically and compared with similar compounds obtained from phthalic acid. The resorcinol compound has also been brominated and acety-lated. The effect of completely saturating and introducing an oxygen bridge in the phthalic acid portion of phthalein dyes has been studied.