1-[2-(Dimethylamino)ethyl]-1H-tetrazole-5-thiol

1-(2-Dimethylaminoethyl)-5-mercaptotetrazole is an impurity of Cefotiam, a semi-synthetic cephalosporin antibiotic.

2-isocyanate-N, N-dimethylethanamine (1 mmol), and sodium azide (1 mmol) were stirred with 2 ml of 2-propanol and 2 ml of water for 3 hours at a temperature of 80°C. The solvent was removed by reducing pressure after acidification using 2N HCl. The desired form of the compound, 1-(2-dimethylamino)ethyl)-1H-tetrazole-5-thiol, was obtained with a yield of 84% by purifying with silica gel column chromatography using methanol and dichloromethane as developing solvents.