3,4-diphenylcyclobut-3-ene-1,2-dione

二氯乙炔

3-氯-4-(吗啉-4-基)-3-环丁烯-1,2-二酮

3,4-bis(4-nitrophenoxy)cyclobut-3-ene-1,2-dione

3-chloro-4-(4-methoxyphenyl)cyclobut-3-ene-1,2-dione