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Regioselective symmetrical bromination of protected 2,2′‐biimidazole
Author(s) -
SanchezGarcia David,
Borros Salvador,
ll Santi,
Borrell Jose I.,
Colominas Carles,
Teixido Jordi
Publication year - 2002
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.5570390418
Subject(s) - chemistry , halogenation , regioselectivity , lithium (medication) , equivalent , medicinal chemistry , n bromosuccinimide , stereochemistry , organic chemistry , catalysis , medicine , biochemistry , endocrinology
Treatment of the benzyl and (trimethylsilylethoxymethyl) SEM protected 2,2′‐biimidazoles, 2a and 2b , with 2 equivalents of N ‐bromosuccinimide (NBS) allows obtaining the 5,5′‐dibromo and 4,4′‐dibromo substituted biimidazoles, 3a and 5b respectively. The use of 4 equivalents of NBS, followed by treatment of the corresponding tetrabromoderivatives 4a and 5b with butyl lithium (BuLi), yields the 4,4′‐dibromoderiva‐tives 5a (G=Bn) and 5b (G=SEM).