Cyanogen Bromide → 5-propyl-1,3,4-oxadiazol-2-amine

To a solution of 5.0 g (47.0 mmol) cyanogen bromide in 50 ml of methanol was added dropwise over a period of 30 min a solution of 4.80 g (47.0 mmol) butyric acid hydrazide in 50 ml of methanol. The mixture was then refluxed for 15 min, and then concentrated in vacuo till cristallisation began. The cristals (9 g) were filtered off, taken up in 60 ml of ethanol. Then 5 g of finely powdered potassium carbonate were added and the suspension was stirred for 5 min at room temperature. The resulting orange suspension was filtered, and the filtrate was concentrated in vacuo. The resulting orange powder (5.5 g) was purified by flash chromatography on silicagel with a 80:10:1 mixture of methylene chloride/methanol/28% ammonia as eluent to yield 3.95 g (31.1 mmol, 66%) of 5-propyl-[1,3,4]oxadiazol-2-ylamine as white cristals, MS: m/e=127 (M+).

1. temperatureThe mixture was then refluxed for 15 min
2. concentrationconcentrated in vacuo till cristallisation
3. filtrationThe cristals (9 g) were filtered off
4. additionThen 5 g of finely powdered potassium carbonate were added
5. filtrationThe resulting orange suspension was filtered
6. concentrationthe filtrate was concentrated in vacuo
7. customThe resulting orange powder (5.5 g) was purified by flash chromatography on silicagel with a 80:10:1 mixture of methylene chloride/methanol/28% ammonia as eluent

ORD record

ord-a1715fa51e7248cd9452fbbbb1013cca

Source dataset

uspto-grants-2003_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06596743B2