Trifluoroacetic acid → HCID 136348453, compound

Participants

Reaction Steps

TFA (0.800 mL) was added to a solution of tert-butyl (4-(1-(4-bromophenyl)-4-oxobutyl)-1-ethyl-3-(pyridin-2-yl)-1H-pyrazol-5-yl)carbamate (0.0400 g, 0.0780 mmol) and DCM (0.800 mL). After about 40 min, reaction monitor by LC-MS (Table 1, Method g) Rt=2.68 min; m/z 395 and 397 (M+H)+indicated conversion to 4-(4-bromophenyl)-1-ethyl-3-(pyridin-2-yl)-1,4,5,6-tetrahydropyrazolo[3,4-b]azepine. Sodium triacetoxyhydroborate (0.083 g, 0.390 mmol) was added in one portion. After about 45 min, the volatiles were removed under reduced pressure. THF (0.8 mL) and 2 M aqueous HCl (0.8 mL) were added. After about 15 min, saturated aqueous NaHCO3 (5 mL) was added. The solution was extracted with EtOAc (2×5 mL). The combined organics were dried over Na2SO4, filtered, and concentrated under reduced pressure. The residue was purified on silica gel (4 g) using a gradient of 50-100% EtOAc in heptane. The fractions containing product were combined and concentrated under reduced pressure to afford an ivory solid. Acetonitrile (0.5 mL) was added. The slurry was diluted with water (4 mL) then sonicated for about 2 min. The organic volatiles were removed under reduced pressure. The mixture was frozen then lyophilized to afford 4-(4-bromophenyl)-1-ethyl-3-(pyridin-2-yl)-1,4,5,6,7,8-hexahydropyrazolo[3,4-b]azepine (0.0239 g, 0.0600 mmol, 77%) as an ivory solid. LC-MS (Table 1, Method h) Rt=2.61 min; m/z 397 and 399 (M+H)+; 1H NMR (400 MHz, DMSO) δ 8.44-8.34 (m, 1H), 7.79-7.75 (m, 1H), 7.70-7.63 (m, 1H), 7.35 (d, J=8.4 Hz, 2H), 7.17-7.11 (m, 1H), 7.05 (d, J=8.4 Hz, 2H), 5.56-5.47 (m, 2H), 4.16-3.94 (m, 2H), 3.33-3.20 (m, 1H), 2.81-2.70 (m, 1H), 2.18-2.07 (m, 1H), 1.92-1.80 (m, 1H), 1.71-1.59 (m, 1H), 1.49-1.35 (m, 1H), 1.30 (t, J=7.1 Hz, 3H).

Provenance & Evidence