3,5-bis-propionamidonitrobenzene 、 5-acetyl-3-[1-(3,5-bis-propionamidophenylamino)ethylidene]-4-hydroxy-2H-pyran-2,6(3H)-dione 以(0.0084 mol) of 3,5-diacetyl-4,6-dihydroxy-2H-pyran-2-one to furnish 5-acetyl-4-hydroxy-3-[1-(3,5-bis-propionamidophenylamino)ethylidene]-2H-pyran-2,6(3H)-dione, m.p. 239°-241° (dec.)的产率得到2,4-二乙酰基-3-氧代戊二酸酐