Ammonium Hydroxide → Ethyl 8-chloro-[1,2,4]triazolo[4,3-a]pyrazin-3-ylcarbamate

Participants

Reaction Steps

A solution of bromine (653 μl, 12.74 mmol) in acetic acid (9 mL) was added to a solution of ethyl 2-(3-chloropyrazin-2-yl)hydrazinecarbonothioylcarbamate (3.523 g, 14.40 mmol) in acetic acid (30 mL) at room temperature and stirred for a further 80 minutes. The mixture was cooled in an ice-bath while 15% ammonium hydroxide solution (180 mL) was added to the reaction mixture, ensuring the reaction temperature remained below 30° C. The mixture was diluted with water (50 mL) and chloroform (120 mL) and filtered. The cake was washed with chloroform (50 mL) and dried under high vacuum at 50° C. to yield ethyl 8-chloro-[1,2,4]triazolo[4,3-a]pyrazin-3-ylcarbamate (1.69 g) as a brown solid.

Provenance & Evidence