105-56-6

13616-37-0

General procedure for the synthesis of ethyl 1H-tetrazole-5-acetate from ethyl cyanoacetate: general method: a mixture of ethyl cyanoacetate (1 mmol), sodium azide (1.25 mmol) and L-proline (30 mol%) in N,N-dimethylformamide (DMF, 5 mL) was stirred and reacted for 1-2 hours at 110°C. The reaction process was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the reaction mixture was cooled to room temperature. The cooled reaction mixture was slowly poured into ice water (15 mL) under stirring. Subsequently, the resulting mixture was acidified with dilute hydrochloric acid under vigorous stirring to pH < 3. If a solid product precipitated after acidification, the solid was collected by filtration and washed with plenty of cold water until the washings were neutral. The resulting solid product was air dried at room temperature to give pure ethyl 1H-tetrazole-5-acetate. If no solid product precipitated after acidification (e.g., when benzyl cyanide or aliphatic nitrile was used as the raw material), the aqueous phase of acidification was extracted with ethyl acetate (2 x 20 mL), and the organic phases were combined and washed with deionized water. The organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure to obtain the corresponding pure ethyl 1H-tetrazole-5-acetate.