Reaction #1726702

Reaction equation

3-Chloro-4-phenyl-1,2,5-thiadiazole

lithium bis(trimethylsilyl)amide

hydrochloric acid

→

3-amino-4-phenyl-1,2,5-thiadiazole

Yield 68.0%

Solvents

THF

THF

Conditions

Workup

1. 1
   Extractionextracted three times into ether (total 300 ml)
2. 2
   WashThe combined organic phases were washed with saturated aqueous sodium bicarbonate and brine
3. 3
   Dryingdried over magnesium sulfate
4. 4
   Concentrationconcentrated in vacuo
5. 5
   workup.DISSOLUTIONThe residue was dissolved in methanol (50 ml)
6. 6
   Temperaturetriethylamine (0.5 ml) was heated
7. 7
   Temperatureto reflux for 15 hr
8. 8
   Concentrationagain concentrated in vacuo

Procedure

3-Chloro-4-phenyl-1,2,5-thiadiazole (3.19 g, 16.2 mmol) in THF (32 ml) at 0° C. was treated dropwise with a solution of lithium bis(trimethylsilyl)amide in THF (17.0 ml, 1.0 M, 17.0 mmol). After 10 min the mixture allowed to warm to ambient temperature for 1.5 hr, treated with 1N hydrochloric acid, and extracted three times into ether (total 300 ml). The combined organic phases were washed with saturated aqueous sodium bicarbonate and brine, and dried over magnesium sulfate and concentrated in vacuo. The residue was dissolved in methanol (50 ml) and triethylamine (0.5 ml) was heated to reflux for 15 hr and again concentrated in vacuo. Flash chromatography on silica gel (ethyl acetate/hexanes) yielded 3-amino-4-phenyl-1,2,5-thiadiazole (1.96 g, 68%) as a colorless solid.

Source