Tetrachlorofluorescein and Some of Its Derivatives.

Abstract

at 9-92 '. It may be purified by crystallization from alcohol, from which the chloroimide separates i n the form of square prisms that melt at 93-94'. From ligroin (b. p. 70-80')) it gives crystals of the same shape, melting at 'the same temperature. It decomposes suddenly, with charring, when heated above 176'. 0.3443 g. subs. gave 0.6079 g. AgHal. Calc. for C7HdONC12Br: Halogen, 56.12; found. 56.14. The mother liquor, left after crystallization of the above described chloroimidoquinone, was evaporated to a small volume and allowed to cool. The solid that separated melted at 111-113') which showed that this material could not be the chloroimide. Further crystallization from alcohol. raised the m. p. to 114-115', but the small quantity of material available made it impossible to secure a product that was entirely pure. The substance crystallized in the form of the irregular scales characteristic of 2-chloro-6-bromo-~-methylquinone described above. A mixture of a pure sample of the latter, m. p. 119') and the product here in question, melted at 115-11g', showing no depression. When the substance to be identified was mixed with a pure sample of 2-chloro-6-bromo-~-methyl-~-chloroimidoquinone, m. p. 93-94 ' , both of which were produced in the same experiment, the mixture melted at 75-86'. Analysis for halogen gave too high a value, which suggests a trace of a higher halogenated product. 0.0785 g. subs. gave 0.1130 g. AgHal. Calc. for C7H402ClBr: Halogen, 49.03; found: 50.06. SUmmq. I. When 4-nitro-m-cresol is chlorinated by passing pure or diluted chlorine into an acetic acid solution of the substance, a mixture of z-chloro-4-nitro-nz-cresol and 6-chloro-~-nitro-m-ceso~, in which the first is present in largest amount, is formed. 2. When 4-nitro-m-cresol is chlorinated by means of a mixture giving so-called nascent chlorine, nothing but z~6-dichloro-~-nitro-m-cresol i s obtained. CHICAGO. ILL. CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF CORNELL UNIVERSITY. ] TETRACHLOROFLUORESCEIN AND SOME OF ITS DERIVATIVES .

Byproduct with Altered Fluorescent Properties Is Formed during Standard Deprotection Step of Hexachlorofluorescein Labeled Oligonucleotides

“…Fluorescein ammonium salt in a dry ammonia stream has been converted to 3,6-diaminoacridine derivative at 180−200 °C in 5 days . However, at lower temperature (110 °C) dry ammonia did not change tetrachloroeosine . In turn, we did not detect 3,6-hydroxyl substitution with water ammonia at temperatures up to 70 °C.…”

Reactions and Uses of Tetrachlorophthalic Anhydride

“…Resorcinol, condensed with the anhydride, yielded tetrachlorofluorescein and tetrachloro-o-fluorescein (35,72,77). From this compound was obtained a Phloxine dye, tetrachloroeosin (8, 9, 72, 77), and the closely related Rose Bengal 3B (8, 9).…”

Preparation of two novel monobrominated 2-(2′,4′-dihydroxybenzoyl)-3,4,5,6-tetrachlorobenzoic acids and their separation from crude synthetic mixtures using vortex counter-current chromatography

“…28 (R28, mainly 2 , Colour Index 45410, phloxine B) are color additives permitted for use in drugs and cosmetics in the U.S. [1]. Their manufacture involves several steps: condensation of two equivalents of resorcinol with either one equivalent of tetrachlorophthalic anhydride [2] or one equivalent of tetrachlorophthalic acid in the presence of a condensing agent [3] to obtain the intermediate 4,5,6,7-tetrachlorofluorescein (TCF in Fig. 1); bromination of TCF to yield the main component of R27; and alkaline hydrolysis of R27 with sodium hydroxide to obtain the main component of R28 (Fig.…”