Chlorosulfonyl isocyanate → 2-Methyl-5-ureido-thiazole-4-carboxylic acid ethyl ester

Participants

Reaction Steps

To a solution of 5-amino-2-methyl-thiazole-4-carboxylic acid ethyl ester (15.0 g, 0.081 mol) in DCM (550 mL) was added chlorosulfonyl isocyanate (8.92 mL, 0.102 mol) dropwise at −78° C. The thick suspension was allowed to warm to RT and stirred for 45 minutes. The resulting precipitate was collected by filtration and dried in vacuo. The resultant white solid was suspended in an aqueous solution of HCl (6 M, 400 mL) and heated at 90° C. for 1 h. The resulting solution was cooled to 0° C. and pH adjusted to 5 with an aqueous solution of NaOH (6 M). The resultant precipitate was collected by filtration and dried in vacuo at 60° C. for 36 h to give the title compound (16.4 g, 89%).

Provenance & Evidence