6-Alkyl-2,5-bisethoxy-3-ethoxycarbonyl-3,6-dihydropyrazine aus Piperazin-2,5-dionen 6-Alkyl-2,5-bisethoxy-3-ethoxycarbonyl-3,6-dihydropyrazines from Piperazine-2,5-diones
6-Alkyl-2,5-bisethoxy-3-ethoxycarbonyl-3,6-dihydropyrazine aus Piperazin-2,5-dionen 6-Alkyl-2,5-bisethoxy-3-ethoxycarbonyl-3,6-dihydropyrazines from Piperazine-2,5-diones