- Phenol-naphthol-benzeine - Synthesis and chromophoric properties. Part 5: Benzeines
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Phenols 4 and 1-naphthol (5) react with benzotrichloride (6) to give benzaurines 7, phenol-naphthol-benzeines 3 and α-naphtholbenzein (1), which were isolated by chromatography. Phenol-naphthol-benzeines 3 are X-/Y-chromophores like α-naphtholbenzeine (1) with two absorption maxima. These are hypsochromically shifted in neutral, in alkaline and in acidic solution, compared with those of 1.
- Kallmayer,Lenze
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p. 534 - 536
(2007/10/03)
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- 5-Oxo-14-phenyl-5H-dibenzo[a,h]xanthene - Part of the indicator 'α-naphtholbenzein'
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The indicator substance α-naphtholbenzein 1/2 is synthesized from 1-naphthol and benzotrichloride. This reaction gives always 5-oxo-14-phenyl-5H-dibenzo[a,h]xanthene (3), too. 3 shows an orange color, which is pH-independent, and an orange fluorescence. Subsequently, the formation of 3 is investigated.
- Kallmayer,Lenze
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p. 393 - 395
(2007/10/02)
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- 4-[(4-hydroxy-1-naphthyl)phenylmethylen]-1(4H)-naphthalinone - The indicator substance from 'α-naphtholbenzein', part 1: Benzeines
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The red brown mixture of E/Z-isomeres 3/6 were isolated from 'α-naphtholbenzein', a mixture of various substances. Compounds 3 and 6 are the real indicator substances in 'α-naphtholbenzein', which is used to indicate titrations of weak bases and acids. The reduction of 3/6 give only the colorless 9. Its 4,4'-connections are proved by 1H-NMR-spectroscopy after OH-methylation.
- Lenze,Kallmayer
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