An improved synthesis of 3-[3-(trifluoromethyl)-3H-1,2-diazirin-3-yl]aniline: A key intermediate in the synthesis of photoaffinity probes

An improved synthesis of 3-3-(trifluoromethyl)-3H-1,2-diazirin-3-yl]aniline, achieving an overall yield of 38% over seven steps is reported. Only three chromatographic separations were needed and the preparation of ～0.7 g of the target compound was demonstrated. The stability of the diazirine in solution at room temperature while exposed to ambient light was studied. No significant degradation of the compound was observed over the course of five weeks in a 130 mM sample and only minor degradation was observed in weaker samples (10, 5, and 2.5 mM), as demonstrated by ¹H and ¹⁹F NMR.