N-bromobutanimide → HCID 58382107, compound

Participants

Reaction Steps

NBS (0.708 g, 3.98 mmol) was added to a solution of 8-ethyl-1-methyl-6-tosyl-1,6-dihydropyrazolo[3,4-d]pyrrolo[2,3-b]pyridine (1.41 g, 3.98 mmol, Preparation #2, Step F) in THF (60 mL). The mixture was allowed to stir at rt. After 16 h additional NBS (0.106 g, 0.597 mmol) was added and reaction was stirred for about 3 h, then another portion of NBS (0.142 g, 0.796 mmol) was added. After another 1 h three equal portions of NBS (0.213 g, 1.19 mmol) were added over about 6 h. The mixture was then diluted with saturated aqueous Na2S2O3 (50 mL) and extracted with EtOAc (2×20 mL). The combined organic layers were dried over MgSO4, filtered and concentrated under reduced pressure. The residue was suspended in Et2O (10 mL) and sonicated for about 3 min. The precipitate was collected by filtration, washed with Et2O (10 mL) and dried in a vacuum oven at about 60° C. for about 3 h to give 3-bromo-8-ethyl-1-methyl-6-tosyl-1,6-dihydropyrazolo[3,4-d]pyrrolo[2,3-b]pyridine (1.3 g, 75%): LC/MS (Table 2, Method c) Rt=1.58 min.; MS m/z: 433 (M+H)+.

Provenance & Evidence