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The synthesis of azoniadithia[6]helicenes
Author(s) -
Sato Kiyoshi,
Okazaki Shuichi,
Yamagishi Takamichi,
Arai Sadao
Publication year - 2004
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570410324
Subject(s) - helicene , chemistry , yield (engineering) , thiophene , salt (chemistry) , proton nmr , nmr spectra database , stereochemistry , medicinal chemistry , spectral line , organic chemistry , molecule , materials science , metallurgy , physics , astronomy
A new short‐step synthesis of 8a‐azonia[6]helicene (1) and the novel dithieno derivatives ( 2 and 3 ) is described. Double photocyclization of 2,8‐distyrylquinolizinium salt (8) gave 1 in 35% yield. Similarly, 2,8‐bis[2‐(2‐thienyl)vinyl]‐ and 2,8‐bis[2‐(3‐thienyl)vinyl]‐quinolizinium salts ( 9 and 10 ) afforded new azonia[6]helicenes containing two thiophene rings at the ends of helix, that is 7a‐azonia‐3,12‐dithia[6]helicene (2) and 7a‐azonia‐1,14‐dithia[6]helicene (3) , in 43 and 35% yields, respectively. The total assignment of their 1 H‐ and 13 C‐nmr spectra was performed by utilizing two‐dimensional and NOE nmr spectroscopic methods.