反应详情

温度

90 °C

To a round bottom flash equipped with an overhead stir motor was added 80 g of polyphosphoric acid. The flask was heated to 90° C. and a finely ground mixture of 3-methyl-1H-indazole-5-carboxlic acid 4e (8.0 g, 45.5 mmol) and thiosemicarbazide (4.1 g (45.4 mmol) was slowly added over a period of 30 min. The resulting mixture was stirred for 24 hr. At this point 200 ml of ice water was added to the solution, and the pH of the resulting mixture was adjusted to 7.0 using solid KOH. A precipitate was formed in the process. The precipitate was isolated by filtration, washed sequentially with water and ether, and dried at reduced pressure, affording 5-(3-Methyl-1H-indazol-5-yl)-[1,3,4]thiadiazol-2-ylamine (4f) (5.50 g, 53% yield) as a tan colored solid. 1H 400 MHz NMR (d6 DMSO), 2.54 (3 H, s), 3.17 (1H, s), 7.54 (1H, d, J=8.0 Hz), 7.83 (1H, t, J=8.0 Hz), 8.06 (1H, s). MS (API-ES) m/z (%): 232 (100%, M++H).

1. customTo a round bottom flash equipped with an overhead
2. additionwas slowly added over a period of 30 min
3. stirringThe resulting mixture was stirred for 24 hr
4. customA precipitate was formed in the process
5. customThe precipitate was isolated by filtration
6. washwashed sequentially with water and ether
7. customdried at reduced pressure