The mixture of 2,9-diazaspiro[5.5]undecan-1-one TFA salt ([1190586-22-1], 1.0 g, 3.5 mmol), 2-chloroquinoxaline ([1448-87-9], 0.77 g, 4.6 mmol), DIPEA (3.7 ml, 21 mmol) and DMAP (22 mg, 0.18 mmol) in ethanol (10 ml) was placed in a microwave tube. The tube was sealed and the suspension was heated at 160° C. for 2 h under microwave conditions. The mixture was filtered and the residue washed with ethanol. The filtrate was concentrated and the precipitate filtered and washed with ethanol. The combined solid material was dissolved in ethyl acetate, washed with water and dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to afford 0.81 g (77%) of the title compound as a pale yellow solid which was not further purified. [1H NMR (400 MHz, DMSO-d6) ♀ ppm 8.79 (s, 1H), 7.78 (d, J=7.8 Hz, 1H), 7.53-7.58 (m, 2H), 7.31-7.39 (m, 2H), 4.22 (dt, J=13.5, 4.4 Hz, 2H), 3.37-3.49 (m, 2H), 3.06-3.15 (m, 2H), 1.91-2.05 (m, 2H), 1.75-1.83 (m, 2H), 1.65-1.75 (m, 2H), 1.44-1.55 (m, 2H); LCMS RtB=2.80 min, [M+H]+=297.2].
