spiro

N,N'-dimethyl-5-hydroxy-5-(1,1,2-trimethyl-2-propenyl)hydantoin

N,N'-dimethyl-5-hydroxy-5-benzylhydantoin

N,N'-dimethyl-5-hydroxy-5-(hydroxymethyl)hydantoin

(Z)-N,N'-dimethyl-5-hydroxy-5-(4-methoxy-1,1,4,4-tetramethyl-2-butenyl)hydantoin