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ChemicalBook CAS DataBase List 7-bromo-[1,2,4]triazolo[1,5-a]pyridin-2-amine
882521-63-3

7-bromo-[1,2,4]triazolo[1,5-a]pyridin-2-amine synthesis

2synthesis methods
[[(4-Bromo-2-pyridinyl)amino]thioxomethyl]-carbamic acid ethyl ester

882521-62-2

7-bromo-[1,2,4]triazolo[1,5-a]pyridin-2-amine

882521-63-3

1-Ethoxycarbonyl-3-(4-bromopyridin-2-yl)thiourea (17.5 g, 57.5 mmol) was mixed with hydroxylamine hydrochloride (20.0 g, 288 mmol) and N-ethyl diisopropylamine (30.1 ml, 173 mmol) in ethanol (367 ml). After stirring for a few minutes at room temperature, the reaction mixture was heated to reflux for 24 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. Water (100 ml) was added to the residue and stirred for 10 min to form a suspension. The solid product was collected by filtration, washed with water and dried to give 7-bromo-[1,2,4]triazolo[1,5-a]pyridin-2-amine (10.71 g, 87.4% yield) as a light yellow solid. Melting point: 190-192°C. Mass spectrum (MS): m/z = 213.0, 215.0 ([M+H]+).

-

Yield: 87.4%

Reaction Conditions:

with hydroxylamine hydrochloride;N-ethyl-N,N-diisopropylamine in ethanol at 25; for 24 h;Product distribution / selectivity;Reflux;

Steps:

35.b
A mixture of hydroxylamine hydrochloride (20.0 g, 288 mmol) and N-ethyldiisopropylamine (30.1 ml, 173 mmol) in ethanol (367 ml) is stirred for a few minutes at room temperature and the mixture is added to l-ethoxycarbonyl-3-(4-bromo-pyridin-2-yl)-thiourea (17.5 g, 57.5 mmol). The resulting mixture is refluxed for 1 day. The solvent is evaporated and 100 ml water is added to the residue. The suspension is stirred for 10 minutes, the solid is collected by filtration, washed with water and dried affording 7-bromo-[l,2,4]triazolo[l,5-a]pyridin-2-amine (10.71 g, 87.4%) as a light yellow solid. Mp.: 190-2°C. MS: m/z= 213.0, 215.0 (M+H+).

References:

F. HOFFMANN-LA ROCHE AG;FLOHR, Alexander;GOBBI, Luca;GROEBKE ZBINDEN, Katrin;KOERNER, Matthias;PETERS, Jens-Uwe WO2012/76430, 2012, A1 Location in patent:Page/Page column 90

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