Chemistry of thienopyridines. XXXIII. Synthetic routes to 5- and 7-substituted thieno[3,2-b]pyridines from theN-oxide

Autor: Clay Higgins, Daniel R. Muchiri, William A. Boisvert, LeRoy H. Klemm, John N. Louris
Rok vydání: 1985
Předmět:
Zdroj: Journal of Heterocyclic Chemistry. 22:1249-1252
ISSN: 1943-5193
0022-152X
DOI: 10.1002/jhet.5570220522
Popis: Thieno[3,2-b]pyridine (1) is oxidized to N-oxide 1a by means of m-chloroperoxybenzoic acid (83%). Compound 1a forms adducts with hydrogen chloride and picric acid and gives ring substitution alpha or gamma to the heteronitrogen atom. Thus, 1a plus nitric and sulfuric acids produces the 7-nitro-N-oxide 1m (63%), or plus phosphorus oxychloride gives a mixture of 5-chloro and 7-chloro (1j) derivatives of 1. Compound 1m is convertible into a variety of other derivatives of 1, viz. 7-chloro-N-oxide, 1j, 7-bromo-N-oxide, 7-nitro and 7-amino. 5-Cyano-1, formed from 1a, is, in turn, transformed into a methyl imidate (93%), cyclic amidines, and a 5-tetrazolyl-1 (91%). These results confirm the prediction that 1a, thieno[2,3-b]pyridine-4-oxide and quinoline 1-oxide should exhibit closely similar (i.e. analogous) chemical reactions.
Databáze: OpenAIRE
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