Abstract Some 3, 6-dialkyl-1, 4-dihydroxy-2, 5-dioxopiperazines were conveniently prepared from the corresponding 3, 6-dialkyl-2, 5-dichloropyrazines via their 1, 4-dioxides and 3, 6- dialkyl-2, 5-dihydroxypyrazine 1, 4-dioxides. On the basis of the examination of pmr, tlc, and glc of the 2, 5-dioxopiperazines derived from the products, it was clarified that all the products were cis-diastereomers.