The condensation of 1, 4-diacetyl-2, 5-piperazinedione with salicylaldehyde gave 1-acetyl- (Z)-3-salicylidene-2, 5-piperazinedione and 3-(N-acetylglycyl) aminocoumarin by ca. 1: 1 ratio. The former was readily converted with t-BuOCl into spiro [3H-benzofuran-2, 3′-(2′, 5′-dioxo)-piperazine] derivative which has a main skeleton of aspirochlorin.