7-Chloro-[1,2,4]triazolo[1,5-a]pyridin-2-ylamine synthesis

Yield: 78.2%

Reaction Conditions:

with hydroxylamine hydrochloride;N-ethyl-N,N-diisopropylamine in ethanol at 25; for 60 h;Reflux;

Steps:

19.f f) 7-Chloro-[ 1 ,2,4]triazolo[ 1 ,5-a]pyridin-2-ylamine
f) 7-Chloro-[ 1 ,2,4]triazolo[ 1 ,5-a]pyridin-2-ylamine A mixture of hydro xylamine hydrochloride (5.35 g, 77.0 mmol, Eq: 5) and N- ethyldiisopropylamine (5.97 g, 8.07 ml, 46.2 mmol, Eq: 3) in ethanol (80 ml) was stirred for a few minutes at 25 °C, then the mixture was added to l-ethoxycarbonyl-3-(4-chloro-pyridin-2- yl)-thiourea (4.0 g, 15.4 mmol, Eq: 1.00) and the resulting mixture was refluxed for 2.5 days (over the weekend). The crude material was applied on Si02 and purified by flash chromatography over a 20 g Si02 column using ethyl acetate 100 % as eluent affording 7- chloro-[l,2,4]triazolo [l,5-a]pyridin-2-ylamine (2.03 g / 78.2%) as a white solid. MS: m/e= 169.1 (M+H+), mp: 189-190°C

References:

F. HOFFMANN-LA ROCHE AG;HOFFMANN-LA ROCHE INC.;FLOHR, Alexander;GROEBKE ZBINDEN, Katrin;KUHN, Bernd;LERNER, Christian;RUDOLPH, Markus;SCHAFFHAUSER, Herve WO2013/178572, 2013, A1 Location in patent:Page/Page column 55