1965 年 85 巻 8 号 p. 679-685
Several new non-symmetric trihydroxyfluoran derivatives substituted with bromine and iodine in 2′-, 4′-, and 2′, 4′-position were synthesized by the method previously reported through condensation of 3-halo- (III), 5-halo- (I), or 3, 5-dihalo-2, 4-dihydroxybenzoylbenzoic acid (II) with phenols (pyrogallol, phloroglucinol, and o-hydroxyhydroquinone triacetate). Coloration pH range of these 18 kinds of bromo-and iodo-trihydroxyfluorans was measured (Table I). The bromo derivatives (Nos. 1-9) generally showed more bathochromic coloration than the iodo derivatives (Nos. 10-18) and intensity of the coloration increased in the order of 4′-halo, 2′-halo, and 2′, 4′-dihalo derivatives.
Examinations were made on the relationship between pH range and coloration in the reaction of bromo- and iodo-trihydroxyfluoran derivatives with metal ions (Table II). It was thereby found that, as in the case of chloro derivatives, the metal ions could be divided into three large groups according to the reaction of the solutions in which they undergo coloration; Bi, Th, Hg in acidity, Pb, Co, Cd, Ni, Zn, La, Cu in neutral to slight acidity, and Mg, Ca, Ba, Al, Sr in alkalinity. The number of metal ions reacting with the iodo derivatives were less than those reacting with the bromo derivatives, and their coloration was generally hypsochromic.