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New symmetric and unsymmetric polyfunctionalized 2,2′‐bipyridines
Author(s) -
De Vains J. B. Regnouf,
Papet A. L.,
Marsura A.
Publication year - 1994
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.5570310463
Subject(s) - chemistry , cyanation , hydroxymethyl , alkylation , nucleophile , polymer chemistry , medicinal chemistry , stereochemistry , organic chemistry , catalysis
Recently, a large number of biheterocycles have been synthesized in order to build macrobicyclic cryp‐tates. To pursue investigations in this field, we prepared new symmetric and unsymmetric functionalized bi‐pyridines and we describe here two synthetic strategies leading to new tetrasubstituted 3 to 15 and trisubsti‐tuted 17 to 29 bipyridines. Modification at the α,α'‐methyl groups and introduction of functionalities in the 4,4′‐positions have been performed after N‐O activation of the starting 6,6′‐dimethyl‐2,2′‐bipyridine unit. In the case of cyano and hydroxymethyl groups, alkylation of the N‐O function followed by a nucleophilic attack with the CN anion or an hydroxymethyl radical allowed us to obtain the dissymmetric species. To understand observed differencies between cyanation and hydroxymethylation processes, the unstable and hygroscopic N ‐methoxybipyridinium salt 30 has been isolated and characterized by nmr. Dibromomethyl compounds 8, 15, 29 were finally obtained in good to moderate yields by the Boekelheide rearrangement followed by a pseudohalogen exchange.