3775-60-8

Under ice bath cooling and stirring conditions, 1.0 mL (16.65 mmol) of formylhydrazine was dissolved in 10 mL of methanol, and 1.76 g (16.62 mmol) of cyanogen bromide was added slowly and dropwise to a 10 mL methanol solution. The reaction mixture was kept at 5°C and the reaction was stirred. Over 1 hour and 30 minutes, 1.82 g (21.6 mmol) of sodium bicarbonate was added to the reaction mixture. After continuing stirring at the same temperature for 15 min, the reaction mixture was allowed to warm up naturally to room temperature and stirred continuously for 22 hrs. Upon completion of the reaction, the insoluble material was removed by filtration and the solvent was subsequently removed by distillation to give 3.12 g of light pink solid. The solid was dissolved in acetonitrile and again filtered to remove insoluble matter and the solvent was removed by distillation from the filtrate. Finally, the resulting solid was washed with ethyl ether to give 0.80 g of the target product 1,3,4-oxadiazol-2-amine as a light reddish white solid.

[1] Patent: US2883391, 1957,
[2] Patent: JP2017/25054, 2017, A. Location in patent: Paragraph 0224
[3] Patent: JP2018/76298, 2018, A. Location in patent: Paragraph 0196