Hydrochloric Acid → 2-Chloro-3-(piperazin-1-yl)pyrazine

Participants

Reaction Steps

Add 4 M HCl in 1,4-dioxane (10 mL) to 3′-chloro-2,3,5,6-tetrahydro-[1,2′]bipyrazinyl-4-carboxylic acid t-butyl ester (6.80 g, 22.76 mmol). Add 1,4-dioxane (40 mL) and subject the reaction to ultrasound then stir at room temperature under nitrogen for 3 hr. Add further HCl in 1,4-dioxane (40 mL) and stir for 1 hr. Add chloroform (400 mL), wash with 2 N sodium hydroxide (200 mL), saturated aq. sodium chloride (100 mL), dry (magnesium sulfate) and concentrate to give 3′-chloro-3,4,5,6-tetrahydro-2H-[1,2′]bipyrazinyl as a yellow oil which crystallized on standing to give a solid (4.0 g, 88%). MS (ES): m/z=199.1 [M+H]+.

Provenance & Evidence