90408-27-8Relevant articles and documents
2,5-Dilithiation of N-Protected Imidazoles. Syntheses of 2,5-Disubstituted Derivatives of 1-Methoxymethyl-, 1-Triphenylmethyl-, and 1-(N,N-Dimethylsulphonamido)-imidazole
Chadwick, Derek J.,Ngochindo, Raphael I.
, p. 481 - 486 (2007/10/02)
The conditions previously established for the dilithiation of 1-methylimidazole are shown to be applicable to 1-methoxymethyl- and 1-triphenylmethyl-imidazole allowing good-yielding syntheses of 1,2,5-trisubstituted imidazole derivatives.The suitability of the 1-substituted (and of other groups) for the N-protection of imidazoles in dilithiation experiments is discussed and the use of the N,N-dimethylsulphamoyl protecting group is proposed. 1-Sulphamoylimidazole undergoes mono- and 2,5-di-lithiation quantitatively at low temperatures and in short reaction times.The results of work-up of the 2,5-dilithio intermediate with 1 mol equiv. of iodomethane or dimethyl sulphate indicate selectivity in favour of reaction at the 5-position.
