Sieben Thesen Zu Edition Von Musik Und Musikalischer Praxis

Dürr, Walther

doi:10.7767/omz.1991.46.10.522

Cited by 2 publications

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“…Photochromic dihydroindolizines have proved to constitute a highly efficient class of versatile molecules information recording or storage, and photoswitches, as well as their recent application in dental materials have made these molecules a highly attractive class of photochromes.…”

Section: Introductionmentioning

confidence: 99%

Photophysical Properties of Biphotochromic Dihydroindolizines. Ring-Opening into Extended Bis-Betaines

et al. 1998

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New photochromic spirodihydroindolizines (DHI) that are mono-(1a-e) or biphotochromic (3a-e) have been prepared. The monophotochromic DHIs 1d and 1e contain sterically highly demanding substituents. Photophysical studies, both static and time-resolved, were carried out with 1 and 3. Monophotochromic DHIs 1a-e show fluorescence and phosphorescence. Temperature decrease produces a hypsochromic shift in the fluorescence spectra. Time-resolved studies demonstrate that the photochromism is based on a one-photon electrocyclic photoreaction of 1 to the colored betaine. Only one transient of 0.6-6 µs lifetime could be detected for the transformation of 1a-e. For the bichromophoric DHIs 3a-e, two different transients were recorded with lifetimes of 1 and 45-680 µs. It was proved that the ring opening 1 f 4 (as well as 3 f 9) results from an excited singlet species, as demonstrated by the absence of an oxygen effect and by sensitization experiments. Viscosity effects underline the conformational transformations involved in the sequence 1 f T f 4 and 3 f T 1 f T 2 f 9 to occur in distinct steps, thus showing the detailed reaction paths of photochromic molecules 1 and 3. 990

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Section: Introductionmentioning

confidence: 99%

Photophysical Properties of Biphotochromic Dihydroindolizines. Ring-Opening into Extended Bis-Betaines

et al. 1998

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“…Among the multitude of photochromic materials they are distinguished by high their efficiency, their cheapness, and their accessibility. This forms the basis of their prospective use in optical lenses, the recording and storage of data [4], and dental materials [5].In the present work we describe the synthesis and photochromic characteristics of novel 2-arylindole systems containing a dihydroindolizine ring. It seemed to us important to couple the qualities of 2-arylindoles, which form the fundamental unit in many biologically active systems [6,7], and those of photochromic molecules.…”

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confidence: 99%

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Derivatives of indole. 143.* synthesis of photochromic derivatives of 2-arylindoles

Gogrichiani

Katsadze

Gavtadze

et al. 2004

Chem Heterocycl Compd

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New derivatives of 2-arylindoles containing (4-pyridyl)alkyl substituents at various positions of the pyrrole ring were synthesized. They react with 2,3-dimethoxycarbonylspirofluorenylcyclopropene with the formation of light-sensitive systems belonging to the photochromic dihydroindolizine class.Photochromic dihydroindolizines form a rich and varied class of light-sensitive compounds [2,3]. Among the multitude of photochromic materials they are distinguished by high their efficiency, their cheapness, and their accessibility. This forms the basis of their prospective use in optical lenses, the recording and storage of data [4], and dental materials [5].In the present work we describe the synthesis and photochromic characteristics of novel 2-arylindole systems containing a dihydroindolizine ring. It seemed to us important to couple the qualities of 2-arylindoles, which form the fundamental unit in many biologically active systems [6,7], and those of photochromic molecules. Model systems of such a type are promising for use as marker molecules in the study of biological processes.A standard and effective method for the production of photochromic dihydroindolizines is the addition of electron-excessive N-heterocyclic bases to spirocyclopropene. Such bases for us were the 1-and 3-(4-pyridyl)alkyl-substituted 2-arylindoles 4a-d and 5a-c that we had synthesized.Indolepyridine is the main structural element of many natural products [8], among which there are antitumor [9] and antidiabetic [10] agents. On this basis compounds 4a-d and 5a-c are of interest in themselves as possible biologically active substances.The initial bases 4a-d and 5a-c were produced by alkylation of the respective 2-arylindoles, obtained by the Fischer method [11] (Scheme 1).The 1-(4-pyridylmethyl)-2-arylindoles 4a-d were obtained by N-alkylation of 2-arylindoles (1) with 4-(chloromethyl)pyridine in the 50% aqueous potassium hydroxide-benzene two-phase system in the presence of tetrabutylammonium bromide.It is known that 4-vinylpyridine in an acidic medium alkylates the indole ring at position 3 [12]. In our case too by boiling 2-arylindoles 1a-c with 4-vinylpyridine 3 we obtained the corresponding 3-[2-(4-pyridyl)ethyl] derivatives 5a-c.

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Sieben Thesen Zu Edition Von Musik Und Musikalischer Praxis

Cited by 2 publications

References 0 publications

Photophysical Properties of Biphotochromic Dihydroindolizines. Ring-Opening into Extended Bis-Betaines

Photophysical Properties of Biphotochromic Dihydroindolizines. Ring-Opening into Extended Bis-Betaines

Derivatives of indole. 143.* synthesis of photochromic derivatives of 2-arylindoles

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