SYNTHESIS OF 2-SUBSTITUTED 1-HYDROXYIMIDAZOLES THROUGH DIRECTED LITHIATION

Benzylation of 3-hydroxyimidazole 1-oxide gave 3-(benzyloxy)imidazole 1-oxide, which was deoxygenated with phosphorous trichloride to produc e 1-(benzyloxy)imidazole. 1-(Benzyloxy)imidazole was deprotonated sele ctively at C-2 by n-butyllithium. The anion formed was reacted with el ectrophiles to give 1-(benzyloxy)imidazoles with carbon; halogen, sili con, or sulfur substituents at the 2-position, Subsequent debenzylatio n afforded 2-substituted 1-hydroxaimidazoles which in turn could be de oxygenated to give 2-substituted imidazoles.