反应详情

2.66 g. of 5,6-diamino-4-butylamino-2-methylnicotinic acid ethyl ester (0.01 mol.) are dissolved in 20 ml. of acetic acid and 5 ml. of water. The mixture is cooled to 5° with stirring. At this temperature, a solution of 0.9 g. of sodium nitrite in 5 ml. of water is showly added dropwise. Stirring is continued for an additional 8 hours. The solvent is distilled off and the residue treated with 20 ml. of water and extracted three times with 10 ml. portions of chloroform. The organic layers are dried with sodium sulfate, filtered and evaporated. The crystalline 7-butylamino-5-methyl-3H-[1,2,3]-triazolo-[4,5-b]pyridine-6-carboxylic acid ethyl ester remains and is recrystallized from methanol, yield 2.3 g. (83%), m.p. 188°-189°.

1. temperatureThe mixture is cooled to 5°
2. stirringStirring
3. distillationThe solvent is distilled off
4. additionthe residue treated with 20 ml
5. extractionof water and extracted three times with 10 ml
6. dry with materialThe organic layers are dried with sodium sulfate
7. filtrationfiltered
8. customevaporated
9. customis recrystallized from methanol, yield 2.3 g