New Polysulfur-Nitrogen Heterocycles by Thermolysis of 1,3λ4δ2,2,4-Benzodithiadiazines in the Hydrocarbon and Fluorocarbon Series
✍ Scribed by Vladimir V. Zhivonitko; Alexander Yu. Makarov; Irina Yu. Bagryanskaya; Yuri V. Gatilov; Makhmut M. Shakirov; Andrey V. Zibarev
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 254 KB
- Volume
- 2005
- Category
- Article
- ISSN
- 1434-1948
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✦ Synopsis
Abstract
In contrast to thermolysis of 1,3λ^4^δ^2^,2,4‐benzodithiadiazine (1) and its 5,6,7,8‐tetrafluoro derivative 2 in dilute (10^–3^ M) hydrocarbon solutions, which leads to persistent 1,2,3‐benzodithiazolyls in nearly quantitative yields, the thermolysis of 1 and 2 (the 6‐6 bicyclic system) in concentrated (0.5 M) solutions at 150–170 °C results in complex mixtures of various polysulfur‐nitrogen heterocycles, in particular differently fused 5‐5‐6, 5‐6‐7 and 5‐6‐6‐6 polycyclic systems that were previously unknown. The products were isolated by column chromatography, and the structures of the 5‐5‐6 (11, 12), 5‐6‐7 (5, 13), and 5‐6‐6‐6 (6, 14, 15) polycyclic systems, as well as the 6‐7 (4) and 5‐6 (16) bicyclic derivatives, confirmed by X‐ray diffraction. The crystal packing of 6 and 11–16 is discussed with special emphasis on π‐stacking interactions. The fluorescent properties of the 5‐6‐6‐6 systems synthesized are reported. An alternative approach to the linear 5‐6‐6‐6 system 15 based on self‐condensation of an R–N=PPh~3~ precursor (R = 4,5,6,7‐tetrafluoro‐1,2,3‐benzodithiazol‐2‐yl) is described, and the free‐radical character of this new reaction is proved. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)