Ethyl Acetate → 5-(5-methyl-1H-1,2,4-triazol-3-yl)-3-[4-(trifluoromethoxy)phenyl]-1,2,4-oxadiazole

Temperature

180 °C

To a solution of 3-(4-(trifluoromethoxy)phenyl)-1,2,4-oxadiazole-5-carbohydrazide (9.7 g, 33.7 mmol) and acetimidamide hydrochloride (4.8 g, 50.5 mmol) in dry THF (300 mL), NaOH (2.0 g, 50.5 mmol) was added at RT. The mixture was refluxed overnight. The solution was cooled, concentrated and ethane-1,2-diol (100 mL) was added. The resulting mixture was heated at 180° C. for 3 h, cooled to RT, diluted with H2O (800 mL), and extracted with EtOAc (3×400 mL). The combined organic layers were washed with H2O (300 mL) and brine (100 mL), dried over Na2SO4, filtered, and concentrated under reduced pressure to afford the crude solid product, which was treated with EtOAc (150 mL). The resulting suspension was stirred at RT for 15 min, and then filtered to afford 4.8 g of the pure desired compound. The remaining filtrate was concentrated and purified by silica gel column chromatography (Petroleum ether:EtOAc=1:1) to afford 1.4 g of another batch of 5-(5-methyl-1H-1,2,4-triazol-3-yl)-3-(4-(trifluoromethoxy)phenyl)-1,2,4-oxadiazole as a white solid-overall 6.2 g, yield 59%. MS (ES+) C12H8F3N5O2 requires: 311. found: 312 [M+H]+.

1. temperatureThe mixture was refluxed overnight
2. temperatureThe solution was cooled
3. concentrationconcentrated
4. additionethane-1,2-diol (100 mL) was added
5. temperaturecooled to RT
6. additiondiluted with H2O (800 mL)
7. extractionextracted with EtOAc (3×400 mL)
8. washThe combined organic layers were washed with H2O (300 mL) and brine (100 mL)
9. dry with materialdried over Na2SO4
10. filtrationfiltered
11. concentrationconcentrated under reduced pressure
12. customto afford the crude solid product, which
13. filtrationfiltered

ORD record

ord-f1efb60d3b0c4ff7bfbb4655ae687a44

Source dataset

uspto-grants-2015_04

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09018380B2