Syntheses and Properties of S2-Bridged Benzidines

Autor: Qin Zhu-Ohlbach, Torsten Reda, Frank Rominger, Rolf Gleiter, Hanns-Ludwig Schmidt
Rok vydání: 1998
Předmět:
Zdroj: European Journal of Organic Chemistry. 1998:2409-2416
ISSN: 1099-0690
1434-193X
DOI: 10.1002/(sici)1099-0690(199811)1998:11<2409::aid-ejoc2409>3.0.co;2-2
Popis: The syntheses of 1,2-benzodithiino[5,4,3-cde][1,2]benzodithiin-2,7-diamine (1) and dithio-bridged benzidine 2 have been achieved. The starting material for the synthesis of 1 was 1,3-diiodo-5-nitrobenzene (15) which was transformed by conventional means into 1,2-bis[3,5-bis(ethylthio)phenyl]diazane (19). The benzidine rearrangement of 19 in the presence of HBF4 at –30 °C yielded 4,4′-diamino-2,2′,6,6′-tetraethylthiobiphenyl (20) in 50 % yield. Treatment of 20 with sodium in ammonia and work-up in the presence of air yielded 1. The latter compound could be reduced with LiAlH4 to the tetrathiol 20a. The starting material for the preparation of 2 was 3-chloro-1-iodo-5-nitrobenzene (23), a side product of the preparation of 15. It was transformed analogously to the preparation of 1 into 1,2-bis(3-ethylthiophenyl)diazane (28). The benzidine rearrangement of 28 in presence of HBF4 at –30 °C afforded 4,4′-diamino-2,2′-bis(ethylthio)biphenyl (29) in 49 % yield. Treatment of 29 with sodium in ammonia and work-up under aerobic conditions yielded 2. Quantitative reduction of 2 to the thiol 29a could be achieved with LiAlH4. The reversible electrochemical reduction of 1 on unmodified glassy carbon electrodes leads to a product to which the structure of 3 was assigned.
Databáze: OpenAIRE
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