Figure 1.

Structures of dantrolene and its derivatives. (a) The structure of dantrolene sodium (Dan). (b) N-(3-azido-5-iodo)benzylated Dan derivative, which is referred to as GIF-0082, was designed as a photoaffinity probe by incorporation of azido group as a photoreactive unit and iodine. (c) GIF-0146 and GIF-0185 are Dan analogues, in which the substituent on the phenyl ring is changed from an electron-withdrawing nitro group to electron-donating iodo and methoxy groups, respectively. (d) GIF-0149-R is another type of Dan derivative in which an alkyl chain is anchored on the hydantoin ring. (e) GIF-0163, N-benzyldantrolene, is the structurally more simplified compound of GIF-0082.