Ammonium Chloride → HCID 86724101, compound

Temperature

0 °C

To a mixture of 2-(1-methyl-5-nitro-1H-pyrazol-3-yl)-1,3,4-oxadiazole (2.56 g, 13.1 mmol), ammonium chloride (4.91 g, 92 mmol) in a 1:1 solution of THF/MeOH (82.6 mL) at about 0° C. was added zinc dust (6.0 g, 92 mmol) portionwise. The reaction was stirred for about 10 min at about 0° C. The ice bath was removed and the reaction stirred at ambient temperature for about 16 h. The reaction mixture was filtered through a pad of Celite® rinsing with MeOH (50 mL). The filtrate was concentrated under reduced pressure. The material was partitioned between DCM (50 mL) and water (10 mL). The aqueous layer was back extracted with DCM (2×50 mL). The combined organic layers were dried over MgSO4, filtered and concentrated under reduced pressure. The aqueous layer was acidified using 1 N HCl to about pH 3 and back extracted with DCM (50 mL). The organic layer was dried over MgSO4, filtered and concentrated under reduced pressure. The organic layer batches were combined to afford 1-methyl-3-(1,3,4-oxadiazol-2-yl)-1H-pyrazol-5-amine (0.67 g, 4.06 mmol, 31%, which was used without further purification). LC-MS (Table 1, Method g) Rt=0.59 min, m/z 166 (M+H)+.

1. customThe ice bath was removed
2. stirringthe reaction stirred at ambient temperature for about 16 h
3. filtrationThe reaction mixture was filtered through a pad of Celite®
4. washrinsing with MeOH (50 mL)
5. concentrationThe filtrate was concentrated under reduced pressure
6. customThe material was partitioned between DCM (50 mL) and water (10 mL)
7. extractionThe aqueous layer was back extracted with DCM (2×50 mL)
8. dry with materialThe combined organic layers were dried over MgSO4
9. filtrationfiltered
10. concentrationconcentrated under reduced pressure
11. extractionback extracted with DCM (50 mL)
12. dry with materialThe organic layer was dried over MgSO4
13. filtrationfiltered
14. concentrationconcentrated under reduced pressure

ORD record

ord-58fa51285dad4023b943816b647f14c1

Source dataset

uspto-grants-2015_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09150592B2