1,2-Dimethoxyethane → 8-bromo-2-(2-isopropyl-2H-[1,2,4]triazol-3-yl)-4,5-dihydro-6-oxa-1,3a-diaza-benzo[e]azulene

Participants

Reaction Conditions

Reaction Steps

9-Bromo-5,6-dihydrobenzo[f]imidazo[1,2-d][1,4]oxazepine-2-carboxamide (4.93 g, 16.0 mmol) was taken up in 1,1-dimethoxy-N,N-dimethylmethanamine (25 mL, 0.18 mol) and 1,2-dimethoxyethane (66.5 mL, 0.640 mol). The heterogeneous mixture was stirred very vigorously and heated at 65° C. for 1 h. LC/MS showed complete consumption of starting material at the end of this period. The reaction mixture was concentrated in vacuo and carried on to the subsequent reaction with no further purification steps applied. The crude product from the previous reaction (5.8 g, 16.0 mmol) was suspended in glacial acetic acid (53.2 mL) and isopropylhydrazine hydrochloride (4.36 g, 39.4 mmol) was added. The mixture was heated at 100° C. for 2 h. The reaction vessel was cooled to room temp and the solvent was removed in vacuo. The resultant residue was dry loaded onto silica gel and purified by ISCO chromatography (120 g column, 100% EtOAc). In total, 2.3 g (39% yield) of 194 was isolated over the two steps. LC/MS (ESI+): m/z 376 (M+H, with halide isotope). 1H NMR (400 MHz, DMSO) δ 8.34 (d, J=8.6, 1H), 7.95 (s, 1H), 7.91 (s, 1H), 7.36 (dd, J=8.7, 2.0, 1H), 7.30 (d, J=2.0, 1H), 5.85 (dt, J=13.3, 6.6, 1H), 4.55 (d, J=15.5, 4H), 1.48 (d, J=6.6, 6H)

Provenance & Evidence