Ethyl orthoformate → Ethyl 1,2,4-oxadiazole-3-carboxylate

To a suspension of ethyl 2-(hydroxyamino)-2-iminoacetate (3 g, 22.71 mmol) in triethylorthoformate (14 mL, 84.08 mmol) was added boron trifluoride diethyl etherate (0.144 mL, 1.14 mmol). It was heated for 90 minutes. The reaction mixture was concentrated under reduced pressure and the residue dissolved in chloroform. The resulting organic layer was washed with aqueous hydrochloric acid 2N (2×80 mL), aqueous sodium bicarbonate 4% (1×80 mL) and water (2×80 mL), it was dried over anhydrous sodium sulphate and the solvent removed under reduced pressure to yield the title compound (2.70 g, 79%) as a yellow oil.

1. temperatureIt was heated for 90 minutes
2. concentrationThe reaction mixture was concentrated under reduced pressure
3. dissolutionthe residue dissolved in chloroform
4. washThe resulting organic layer was washed with aqueous hydrochloric acid 2N (2×80 mL), aqueous sodium bicarbonate 4% (1×80 mL) and water (2×80 mL), it
5. dry with materialwas dried over anhydrous sodium sulphate
6. customthe solvent removed under reduced pressure

ORD record

ord-bd97b84e6d7045a19546339bbf3e0cd5

Source dataset

uspto-grants-2012_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08258122B2