Reaction #1135832

Reaction equation

KOH

methyl 7-(5-bromo-1H-benzimidazol-2-yl)heptanoate

hydroxylamine

→

7-(6-bromo-1H-benzimidazol-2-yl)-N-hydroxy heptanamide

Yield 52.8%

Solvents

THF

Conditions

Workup

1. 1
   Concentrationbriefly concentrated
2. 2
   workup.ADDITIONby adding 1 N HCl solution until pH was 7
3. 3
   FiltrationThe light yellow precipitate was collected by filtration
4. 4
   Otherpump-dried

Procedure

To a solution of methyl 7-(5-bromo-1H-benzimidazol-2-yl)heptanoate (100 mg, 0.295 mmol) in THF at 0° C. was added 50% hydroxylamine solution (0.17 mL, 2.70 mmol). To this was added KOH (0.74 mL, 1M in MeOH, 0.74 mmol) dropwise. The reaction was stirred at 0° C. for 2 hr, briefly concentrated and neutralized by adding 1 N HCl solution until pH was 7. The light yellow precipitate was collected by filtration and pump-dried to give 7-(6-bromo-1H-benzimidazol-2-yl)-N-hydroxy heptanamide 15 (53 mg). The filtrate was extracted with ethyl acetate, dried and concentrated. The residue was purified by column to give another portion of the desired product 15 (16 mg). LCMS (M+1 @retention time): 340@1.283 min (LC conditions: 1. Column: YMC, C-18 ODS, 50×4.6 mm 0.5 u; 2. Mobile phase: A 0.05% TFA in water and B 0.05% TFA in acetonitrile; 3. Flow rate 1.2 mL/min; Gradient program: 20% B to 100% B in 3 min).

Source