Triphosgene → 6-Bromo-8-chloro-1,2,4-triazolo[4,3-a]pyrazin-3(2H)-one

Participants

Reaction Steps

A solution of 2.50 g of the product of Step C in THF (60 mL) was stirred as 3.32 g of triphosgene was added in portions to provide a tan suspension. A homogeneous solution was obtained after 30 min. and the excess phosgene was destroyed by the careful addition of water and the mixture was extracted with EtOAc. The organic extracts were washed with sat. sodium chloride solution, dried over magnesium sulfate, filtered, and concentrated to afford 6-bromo-8-chloro-2H-[1,2,4]triazolo[4,3-a]pyrazin-3-one as a light yellow solid. MS (M+H−)=280.1.

Provenance & Evidence