反应详情

To an ice cold and stirred solution of 5-mercapto-1H-tetrazole-1-acetic acid (320 mg) in methanol (3 ml) are added triethylamine (0.33 ml) and N,N'-dicyclohexylcarbodiimide (495 mg), and th mixture is stirred for 7 hours. To this solution is added a solution of methoxyamine hydrochloride (33.4 mg) and triethylamine (56 μl) in methanol (0.3 ml). After the addition of a further amount of N,N'-dicyclohexylcarbodiimide (124 mg), the mixture is left stand at room temperature overnight. The reaction mixture is concentrated under reduced pressure to about 1 ml and then diluted with ethyl acetate (8 ml) and 5% sodium hydrogen carbonate (7 ml). After the separated solid (461 mg) is removed by filtration, the filtrate is saturated with sodium chloride and diluted with ethyl acetate-methyl ethyl ketone mixture (1:1). The mixture is acidified to pH 1 with hydrochloric acid and extracted with ethyl acetate. The extract is dried over magnesium sulfate and concentrated under reduced pressure to give 5-mercapto-1H-tetrazole-1-acetohydroxamic acid methyl ester (375 mg), identical with the product prepared with N,N'-carbonyldiimidazole.

1. waitthe mixture is left stand at room temperature overnight
2. concentrationThe reaction mixture is concentrated under reduced pressure to about 1 ml
3. additiondiluted with ethyl acetate (8 ml) and 5% sodium hydrogen carbonate (7 ml)
4. customAfter the separated solid (461 mg) is removed by filtration
5. additiondiluted with ethyl acetate-methyl ethyl ketone mixture (1:1)
6. extractionextracted with ethyl acetate
7. dry with materialThe extract is dried over magnesium sulfate
8. concentrationconcentrated under reduced pressure