Diisopropylethylamine → 6-Bromo-[1,2,4]triazolo[1,5-a]pyridin-2-amine

Participants

Reaction Conditions

Reaction Steps

To a suspension of hydroxylamine hydrochloride (409.2 g, 5.888 mol) in EtOH/MeOH (1:1, 2.5 L) was added N,N-diisopropylethylamine (606.1 mL, 3.480 mol), the mixture was stirred at room temperature (20° C.) for 1 h. 1-(6-Bromo-pyridin-2-yl)-3-carboethoxy-thiourea (2) (352.8 g, 1.160 mol) was then added and the mixture slowly heated to reflux (Note: bleach scrubber required to quench H2S evolved). After 2 h at reflux the mixture was allowed to cool and filtered to collect the precipitated solid. The collected solid was washed successively with water (1.0 L), EtOH/MeOH (1:1, 1.0 L) and diethyl ether (500 mL) then air-dried to afford the title compound as a white solid (169.2 g, 69%). No further purification was required.

Provenance & Evidence