- From liquid to solid-state fluorescence: Tricyclic lactones based on 4-hydroxy-1,3-thiazoles
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This work describes the synthesis of a series of tricyclic lactones based on 4-hydroxy-1,3-thiazoles prepared by the classic Hantzsch synthesis. The tricyclic lactones are more rigid than the parent 4-hydroxythiazoles and are featured not only by fluorescence in solution, but also in the solid state. An extension of the chromophoric system was successfully realized by integration of the benzothiazole substructure, thus resulting in bathochromic shifts of absorption and also fluorescence. The new synthesized lactones additionally show interesting properties in solution, whereby the initial blue fluorescence changes dramatically with a variation of the pH value. Georg Thieme Verlag Stuttgart · New York.
- Calderón Ortiz, Lorena K.,Würfel, Hendryk,T?uscher, Eric,Wei, Dieter,Birckner, Eckhard,G?rls, Helmar,Beckert, Rainer
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p. 126 - 134
(2014/01/06)
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- A new synthesis of dehydroluciferin [2-(6′-hydroxy-2′- benzothiazolyl)-thiazole-4-carboxylic acid] from 1,4-benzoquinone
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A new synthesis of dehydroluciferin [2-(6′-hydroxy-2′- benzothiazolyl)-thiazole-4-carboxylic acid], the oxidative product of luciferin, has been realized starting from 1,4-benzoquinone. Reaction of this compound with l-cysteine ethyl ester, followed by an oxidation-cyclization step afforded 2-carbethoxy-6-hydroxybenzothiazole that was in situ hydrolyzed and decarboxylated to 6-hydroxybenzothiazole. The tert-butyl(dimethyl)silyl ether of this key intermediate was subjected to α-lithiation followed by formylation with DMF, and the resulting aldehyde condensed with l-cysteine ethyl ester. Dehydrogenation of the intermediate thiazolidine followed by deprotection afforded dehydroluciferin in 35% overall yield from 1,4-benzoquinone (69% from 6-hydroxybenzothiazole).
- Ciuffreda, Pierangela,Casati, Silvana,Meroni, Giuseppe,Santaniello, Enzo
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p. 5893 - 5897
(2013/07/27)
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