Structure-activity relationship study of [1,2,3]thiadiazole necroptosis inhibitors.

Necroptosis is a regulated caspase-independent cell death mechanism that results in morphological features resembling non-regulated necrosis. This form of cell death can be induced in an array of cell types in apoptotic deficient conditions with death receptor family ligands. A series of [1,2,3]thiadiazole benzylamides was found to be potent necroptosis inhibitors (called necrostatins). A structure-activity relationship study revealed that small cyclic alkyl groups (i.e. cyclopropyl) and 2,6-dihalobenzylamides at the 4- and 5-positions of the [1,2,3]thiadiazole, respectively, were optimal. In addition, when a small alkyl group (i.e. methyl) was present on the benzylic position all the necroptosis inhibitory activity resided with the (S)-enantiomer. Finally, replacement of the [1,2,3]thiadiazole with a variety of thiophene derivatives was tolerated, although some erosion of potency was observed.