Ethyl orthoformate → [1,2,4]Triazolo[4,3-a]pyridine

2-Hydrazinylpyridine (5.06 g, 46.4 mmol) was treated with triethoxymethane (50.2 mL, 302 mmol) and the mixture was heated to reflux for 4 hours with nitrogen flowing over the top of the air condenser. The air condenser was replaced with a small distillation head and the low boiling solvents (75-80° C.) were removed from the system. Heating continued for 16 hours. The reaction was cooled to ambient temperature and concentrated in vacuo to a dark residue. The residue was chromatographed on SiO2 eluting with a gradient of 6% NH4OH in MeOH/ethyl acetate. The desired product was isolated as a light orange solid (4.2 g). MS APCI (+) m/z 120.0 (M+1) detected.

1. temperaturethe mixture was heated
2. temperatureto reflux for 4 hours with nitrogen flowing over the top of the air condenser
3. customthe low boiling solvents (75-80° C.) were removed from the system
4. temperatureHeating
5. concentrationconcentrated in vacuo to a dark residue
6. customThe residue was chromatographed on SiO2 eluting with a gradient of 6% NH4OH in MeOH/ethyl acetate

ORD record

ord-0218b615edfa4a419b9bd8030cb4238b

Source dataset

uspto-grants-2015_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08987251B2