Synthesis of Anthryl-Substituted Bithienylpyridines and their N-Methylpyridinium Salts

Franz Effenberger; Jochen M. Endtner; Burkhard Miehlich; Jürgen S. R. Münter; Martin S. Vollmer

doi:10.1055/s-2000-6410

Synthesis 2000; 2000(9): 1229-1236
DOI: 10.1055/s-2000-6410

paper

© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to criminal prosecution. This applies in particular to photostat reproduction, copying, cyclostyling, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.

Synthesis of Anthryl-Substituted Bithienylpyridines and their N-Methylpyridinium Salts

Franz Effenberger^* , Jochen M. Endtner, Burkhard Miehlich, Jürgen S. R. Münter, Martin S. Vollmer

^*Institut für Organische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany; Fax + 49(7 11)6 85 42 69; E-mail: franz.effenberger@po.uni-stuttgart.de

Abstract

als PDF herunterladen Alle Artikel dieser Rubrik

The synthesis of bithiophenes with anthracene and pyridine as terminal groups is described. 3- and 4-thienylpyridines 3, derived from thiopheneboronic acid 1 and the respective bromopyridines 2a, b, were coupled with 2-(9-anthryl)-5-iodothiophene 4 to give the isomeric (9-anthryl)bithienylpyridines 5a, b. In order to introduce a methylene spacer between the donor anthracene and bithiophene, 5-(2,2′-bithienyl)magnesium bromide 7 was reacted with 2 to yield the bithienylpyridines 9a, b. The reaction of 9 with 9-hydroxymethylanthracene 10 gave 3- and 4-(9-anthrylmethyl)bithienylpyridines 11a, b. The linkage of pyridine to bithiophene via a methylene spacer was reached by reacting lithiobithiophene with the isomeric pyridinecarbaldehydes 14a, b. Dehydroxylation of the resulting carbinols 15a, b with NaBH₃CN/ZnI₂, however, afforded the N-cyanoborane adducts 16a, b, which were transformed to the desired 3- and 4-(bithienylmethyl)pyridines 18a, b by heating either in EtOH or in 6 N HCl. Pyridines 5, 9, 11, and 18 were methylated with CF₃SO₃Me in CH₂Cl₂ or Et₂O as solvent to yield the corresponding pyridinium triflates 6, 12, 13, and 19 in high purity.

aryl-aryl coupling - donor-acceptor systems - electron transfer - oligothiophenes

PDF (141 kb)