Darstellung von 1,2‐Benzisothiazolen und einige Folgereaktionen

“…Like the aldehyde 1, the nitrile 6 readily condenses with methyl thioglycolate in the presence of base to give methyl 3-amino-4,11-dimethoxyanthra[2,3-b]thiophene-5,10-dione-2-carboxylate (7) in high yield (85%). An interesting method has been proposed for the synthesis of benzoisothiazoles based on condensation of aromatic carbonyl compounds containing an ortho-positioned halogen with ammonia in the presence of sulfur [10]. Similarly to the unsubstituted anthra[2,3-b]isothiazole-5,10-dione reported in this work we prepared 4,11-dimethoxyanthra[2,3-d]isothiazole-5,10-dione (8) (Table 1).…”

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confidence: 87%

“…Anthra [2,3-d]thiazole-5,10-dione [3] itself and the majority of its derivatives have been patented as vat dyes, but latterly derivatives have found use as dichroic dyes for liquid crystals [4,5] and its photochromic derivatives have been patented as active media for CD discs [6]. Anthra[2,3-b]thiophene-5,10-dione (of which seven derivatives [7][8][9] have been reported) and anthra [2,3-d]isothiazole-5,10-dione [10] have been studied less. The synthesis and study of the spectroscopic properties of derivatives of this series can have _______ * For Communication 5 see [1].…”

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confidence: 99%

Heterocyclic analogs of 5,12-naphthacenequinone 6. Synthesis of 4,11-dimethoxy derivatives of anthra-[2,3-b]thiophene-5,10-dione and anthra[2,3-d]isothiazole-5,10-dione

Shchekotikhin

Lusikov

Buyanov

et al. 2007

Chem Heterocycl Compd

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Annelation of a heterocyclic fragment with the anthraquinone chromophore significantly affects the photochemical properties of a compound hence the synthesis of heterocyclic analogs of naphthacenequinone and a study of the relationship between chemical structure and spectroscopic properties allows us to direct the synthesis of a compound with targeted spectroscopic and photochemical characteristics. It was found that derivatives of the heterocyclic analogs of naphthacenequinone containing α-alkoxy groups (e.g. 4,11-dimethoxy derivatives of naphtho[2,3-f]indazole-5,10-diones [2]) show fluorescence with large Stokes shift values. Continuing a systematic study of heterocyclic analogs of naphthacenequinone analogs we have prepared and studied the spectroscopic properties of the methoxy derivatives of several thio analogs of 5,12-naphthacenequinone.Analysis of the literature data has shown that the most studied class of thio analogs of 5,12-naphthacenequinone are anthra[2,3-d]thiazole-5,10-diones amongst which series about 40 derivatives have been obtained up to this time. Anthra[2,3-d]thiazole-5,10-dione [3] itself and the majority of its derivatives have been patented as vat dyes, but latterly derivatives have found use as dichroic dyes for liquid crystals [4,5] and its photochromic derivatives have been patented as active media for CD discs [6]. Anthra[2,3-b]thiophene-5,10-dione (of which seven derivatives [7-9] have been reported) and anthra[2,3-d]isothiazole-5,10-dione [10] have been studied less. The synthesis and study of the spectroscopic properties of derivatives of this series can have _______ * For Communication 5 see [1].

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“…One of the most successful methods for the synthesis of 3-aminothiophenes 95 is the addition of an aryl isothiocyanate to active methylenenitrile compounds 84 in an alkaline medium, followed by heterocyclization of intermediate 94 with α-haloketones (Scheme 26) [174,[189][190][191][192][193][194][195][196][197][198]. o-Mercaptonitriles 96 reacted with α-haloketones to give 3-aminothiophenes 98 (Scheme 27) [199][200][201].…”

Section: Thiophenes and Their Fused Derivativesmentioning

confidence: 99%