Triphosgene → 8-bromo-7-chloro-[1,2,4]triazolo[4,3-a]pyridin-3(2H)-one

To a stirring solution of triphosgene (5.766 g, 19.43 mmol) in anhydrous THF (50 mL) at room temperature was added 1-(3-bromo-4-chloropyridin-2-yl)hydrazine (1.438 g, 70% pure) portion-wise over 15 min. The resulting suspension was stirred under argon at room temperature overnight, then cooled at 0° C. and quenched carefully by slow addition of water (30 mL). The resulting yellowish suspension was filtered, and the solid collected was washed with water (20 mL×3), then diethyl ether (5 mL), and dried in a 60° C. vacuum oven to obtain 0.525 g of the title compound, 8-bromo-7-chloro-[1,2,4]triazolo[4,3-a]pyridin-3(2H)-one as an off-white solid. HPLC/MS: retention time=1.93 min, [M+H]+=248.

1. temperaturecooled at 0° C.
2. customquenched carefully by slow addition of water (30 mL)
3. filtrationThe resulting yellowish suspension was filtered
4. customthe solid collected
5. washwas washed with water (20 mL×3)
6. dry with materialdiethyl ether (5 mL), and dried in a 60° C. vacuum oven

ORD record

ord-d4fc0c09bad74ce793d5d7d1bc334305

Source dataset

uspto-grants-2009_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07572808B2