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The synthesis of new azoniathiahelicenes
Author(s) -
Sato Kiyoshi,
Katayama Yuu,
Yamagishi Takamichi,
Arai Sadao
Publication year - 2006
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.5570430127
Subject(s) - helicene , chemistry , knoevenagel condensation , yield (engineering) , salt (chemistry) , condensation , proton nmr , medicinal chemistry , stereochemistry , organic chemistry , molecule , catalysis , materials science , physics , metallurgy , thermodynamics
AbstractSynthesis of new azonia derivatives of thia[6]helicene ( 1 ) and thia[7]helicene ( 2 ) is described. The Knoevenagel condensation of 2‐methylbenzothieno[3,2‐ a ]quinolizinium salt ( 8 ) with appropriate arylaldehydes yielded 2‐(arylvinyl)benzothieno[3,2‐ a ]quinolizinium salts ( 9 and 10 ), respectively. Photocyclization of 2‐styrylbenzothieno[3,2‐ a ]quinolizinium salt ( 8 ) gave 7a‐azonia‐5‐thia[6]helicene ( 1 ) in 63% yield. Similarly, 2‐[2‐(2‐naphthyl)vinyl]benzothieno[3,2‐ a ]quinolizinium salt ( 10 ) afforded 7a‐azonia‐5‐thia[7]helicene ( 2 ) in 56% yield. The complete and unambiguous assignment of their 1 H‐ and 13 C‐nmr spectra was performed by utilizing two‐dimensional nmr spectroscopic methods.