Cyclobutylamine → 1-cyclobutyl-1H-imidazole-4-carboxylic acid ethyl ester

Participants

Reaction Steps

Ethyl 3-(dimethylamino)-2-isocyanoacrylate (WO 2007042545) (45 g, 0.27 mol) was added to cyclobutylamine (50 g, 0.70 mol) and heated to reflux for 2 hours. The solution was then cooled and concentrated. The residue was purified by column chromatography over silica gel (3:1 EtOAc:Heptane). The oily residue was triturated with TBME:heptane (1:1) and the resulting solid was collected and dried, giving 1-cyclobutyl-1H-imidazole-4-carboxylic acid ethyl ester (35 g, 67%, second crop not harvested). 1-Cyclobutyl-1H-imidazole-4-carboxylic acid ethyl ester (35 g, 0.21 mol) was dissolved in 6 N HCl (300 mL) and refluxed for 1 day. The solution was concentrated to dryness in vacuo. The solid was azeotroped with toluene, triturated with toluene and then dried under vacuum, giving the title compound 88% yield, 37.2 g, m/z 167 [M+H]+.

Provenance & Evidence