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Syntheses and Properties of S 2 ‐Bridged Benzidines
Author(s) -
ZhuOhlbach Qin,
Gleiter Rolf,
Rominger Frank,
Schmidt HannsLudwig,
Reda Torsten
Publication year - 1998
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199811)1998:11<2409::aid-ejoc2409>3.0.co;2-2
Subject(s) - benzidine , chemistry , nitrobenzene , yield (engineering) , biphenyl , diamine , electrochemistry , medicinal chemistry , ammonia , sodium tetraphenylborate , organic chemistry , electrode , catalysis , ion , materials science , metallurgy
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 HBF 4 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 LiAlH 4 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 HBF 4 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 LiAlH 4 . The reversible electrochemical reduction of 1 on unmodified glassy carbon electrodes leads to a product to which the structure of 3 was assigned.