Cesium Carbonate as an Efficient Base for Alkylation of 3-(1H-Imidazol-4-yl)pyridine

Abstract

Regioselective 1-alkylation of 3-(1H-imidazol-4-yl)pyridine using bromoacetaldehyde diethyl acetal in the presence of cesium carbonate has been achieved. Selective isolation of the desired 1-alkylated 3-(1H-imidazol-4-yl)pyridine product as a hydrochloride salt, there by avoiding the need for chromatography, is described.

Keywords:

• Alkylation
• cesium carbonate
• macrolides
• pyridyl imidazole
• regioselective

Notes

Notes. Entries 1–9 and 12, base used 1–3 equivalents; entry 10, base used 2 equivalents; entry 11, base used 1.1 equivalents; entries 6 and 11, additives used 0.25 equivalents; entry 9, base used 2 equivalents and 3 equivalents of 5b were used; entry 10, base used 2 equivalents and 1.5 equivalents of 5b were used; and entry 11, base used 1.1 equivalents and 1.1 equivalents of 5b were used.