7-Aza-14,15-dioxadispiro[5.1.5.2]pentadecane

Dispiro[1,2,4-dioxazolidine-3,1':5,1''-dicyclohexane]

Dispiro[cyclohexane-1,3'-[1,2,4]dioxazolidine-5',1''-cyclohexane]