Diisopropylethylamine → Tert-butyl 4-(3-bromoimidazo[1,2-b]pyridazin-6-yl)-1,4-diazepane-1-carboxylate

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Reaction Steps

A stirred solution of 3-bromo-6-fluoroimidazo[1,2-b]pyridazine (1.6 g, 7.6 mmol), tert-butyl 1,4-diazepane-1-carboxylate [112275-50-0] (4.4 mL, 22.6 mmol), and Hunig's base [7087-68-5] (5.3 mL, 30.4 mmol) in 2-propanol (25 mL) was heated to 65° C. for 3d then partitioned between brine and ethyl acetate. The extract was dried (CaSO4) and evaporated to provide 5.9 g of clear orange liquid which was flash chromatographed (silica gel eluted with 10% (v/v) methanol/ethyl acetate) and crystallized from ethyl acetate/heptane to afford 2.0 g of white powder, mp. 101-102° C. 1H NMR (400 MHz, DMSO-d6) δ ppm (rotomers present) 1.03 (s, 5H) 1.17 (s, 4H) 1.73 (br. s., 1H) 1.85 (br. s., 1H) 2.43-2.47 (m, 1H) 3.20-3.29 (m, 3H) 3.49 (d, J=5.51 Hz, 1H) 3.55-3.66 (m, 3H) 3.70-3.79 (m, 2H) 7.05 (d, J=9.92 Hz, 1H) 7.49 (d, J=7.28 Hz, 1H) 7.78 (d, J=9.70 Hz, 1H). 13C NMR (100 MHz, DMSO-d6) δ ppm (rotomers present) 24.50, 24.83, 27.45, 27.61, 44.10, 44.78, 44.83, 45.33, 47.58, 47.74, 48.01, 48.09, 78.11, 78.27, 98.80, 109.23, 109.61, 125.65, 125.77, 130.81, 130.89, 136.07, 153.01, 153.18, 153.90, 154.19. LRMS (ESI) m/z 396.1/398.1 [(M+H)]+, calc'd for C16H22BrN5O2: 396.29.

Provenance & Evidence