The synthesis of aryl 4‐nitro‐5‐imidazolyl sulfone radiation sensitizers sterically protected against glutathione reaction

2,6‐Disubstituted aryl 1‐methyl‐4‐nitro‐5‐imidazolyl sulfones 4 and aryl 1‐neopentyl‐2‐tert‐butyl‐4‐nitro‐5‐imidazolyl sulfones 10 have been synthesized and tested as radiation sensitizers of hypoxic carcinoma cells. These sterically crowded imidazoles show decreased displacement reactivity with glutathione at C‐5, a major metabolic reaction known to deplete effective plasma drug levels in traditional aryl imidazolyl sulfone radiation sensitizers.