The cyclization of ethyl 2-(2-thienyl)glyoxylate (I) with ethylenediamine (II) in refluxing ethanol gives 3-(2-thienyl)-1,2,5,6-tetrahydropyrazin-2-one (III), which is reduced with H2 over Raney Nickel (RaNi) in hot ethanol at 50 bar.