3,4-二甲氧基-3-环丁烯-1,2-二酮

3-(1-甲基乙氧基)-4-(三丁基锡烷基)-3-环丁烯-1,2-二酮

4-hydroxy-2,3-di(propan-2-yloxy)cyclobut-2-en-1-one

3-hydroxy-4-(N-phenylanilino)cyclobut-3-ene-1,2-dione

3-propan-2-yl-4-propan-2-yloxycyclobut-3-ene-1,2-dione