A mixture of tert-butyl {1-[4-(2-chloro-9H-imidazo[1,2-d]pyrido[2,3-b][1,4]benzodiazepin-3-yl)phenyl]cyclobutyl}carbamate (55 mg, 0.092 mmol), methyl 2-hydroxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzoate (48 mg, 0.18 mmol), bis(di-tert-butyl(4-dimethylaminophenyl)phosphine)dichloropalladium(II) (7 mg, 0.009 mmol), and 2M Na2CO3 aq. (0.092 mL, 0.18 mmol) in DMF (2.5 mL) was treated with microwave (160° C. for 1 hour). The reaction mixture was added potassium carbonate (30 mg, 0.22 mmol) and iodomethane (0.050 mL, 0.80 mmol) and stirred at r.t for 8.5 hours. The mixture was diluted with AcOEt, washed with water(×3), brine, dried over Na2SO4, then filtrated through Celite pad. The filtrate was concentrated and the residue was purified by preparative thin-layer chromatography (n-hexane/AcOEt=1:2) to afford the desired product (33 mg, 57%) as a pale yellow solid. 1HNMR (CDCl3) 400 MHz δ: 8.16 (dd, J=8.0 Hz and 1.1 Hz, 1H), 8.01 (d, J=4.0 Hz, 1H), 7.70 (d, J=8.6 Hz, 1H), 7.39 (d, J=8.6 Hz, 2H), 7.31 (td, J=8.0 Hz and 1.1 Hz, 2H), 7.18-7.16 (m, 2H), 7.11-7.07 (m, 1H), 6.95 (d, J=8.0 Hz, 1H), 6.80-6.76 (m, 1H), 6.59 (dd, J=7.7 Hz and 4.9 Hz, 1H), 6.24 (s, 1H), 5.09 (br s, 1H), 3.92 (s, 3H), 2.59-2.40 (m, 4H), 2.19-2.12 (m, 1H), 1.93-1.88 (m, 1H), 1.40 (br s, 9H). LCMS: 630 [M+H].
