反应详情

A solution of 1-methyl-1H-tetrazole-5-thiol (23 g) in dry tetrahydrofuran (80 ml) was added over 20 minutes with stirring under dry nitrogen atmosphere to a n-butyllithium (250 ml, 15% in hexane) solution in dry tetrahydrofuran (250 ml) precooled to -15° to -10° C. After stirring at the same temperature for 40 minutes, the mixture was cooled to -60°±5° C. and thereto was added dropwise a solution of diethyl oxalate (28.95 g) in dry tetrahydrofuran (80 ml) over 30 min. The reaction mixture was stirred at -60°±5° C. for 1.5 hours. 10% Aqueous hydrochloric acid (72 ml) was added with stirring and the separated aqueous layer (pH 7.5) was adjusted to pH 2.5 with 10% hydrochloric acid and extracted with ethyl acetate (200 ml×3). The combined extracts were dried over magnesiusm sulfate and evaporated to give oily residue of 1-ethoxalylmethyl-1H-tetrazole-5-thiol (34.3 g).

1. customprecooled to -15° to -10° C
2. temperaturethe mixture was cooled to -60°±5° C.
3. stirringThe reaction mixture was stirred at -60°±5° C. for 1.5 hours
4. stirringwith stirring
5. extractionextracted with ethyl acetate (200 ml×3)
6. customThe combined extracts were dried
7. customevaporated