Diisopropylethylamine → 5-Bromo-[1,2,4]triazolo[1,5-a]pyridin-2-amine

Temperatur

20 °C

To a suspension of hydroxylamine hydrochloride (101.8 g, 1.465 mol) in EtOH/MeOH (1:1, 900 mL) is added N,N-diisopropylethylamine (145.3 mL, 0.879 mol) and the mixture is stirred at room temp. (20° C.) for 1 h. 1-(6-Bromo-pyridin-2-yl)-3-carboethoxy-thiourea (2) (89.0 g, 0.293 mol) is then added and the mixture slowly heated to reflux (Note: bleach scrubber is required to quench H2S evolved). After 3 h at reflux, the mixture is allowed to cool and filtered to collect the precipitated solid. Further product is collected by evaporation in vacuo of the filtrate, addition of H2O (250 mL) and filtration. The combined solids are washed successively with H2O (250 mL), EtOH/MeOH (1:1, 250 mL) and Et2O (250 mL) then dried in vacuo to afford the triazolopyridine derivative (3) as a solid. The compound may be used as such for the next step without any purification. 1H (400 MHz, DMSO-d6) δ 7.43-7.34 (2H, m, 2×aromatic-H), 7.24 (1H, dd, J 6.8 and 1.8 Hz, aromatic-H), 6.30 (2H, br, NH2); m/z 213/215 (1:1, M+H+, 100%).

1. temperaturethe mixture slowly heated
2. temperatureto reflux
3. custom(Note: bleach scrubber is required to quench H2S evolved)
4. temperatureAfter 3 h at reflux
5. temperatureto cool
6. filtrationfiltered
7. customto collect the precipitated solid
8. filtrationFurther product is collected by evaporation in vacuo of the filtrate, addition of H2O (250 mL) and filtration
9. washThe combined solids are washed successively with H2O (250 mL), EtOH/MeOH (1:1, 250 mL) and Et2O (250 mL)
10. customthen dried in vacuo

ORD-Eintrag

ord-97784dd42554461992455f88bebb4fcb

Quelldatensatz

uspto-grants-2012_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08088764B2