Reaction #338186

Reaction equation

4-aminobutyraldehyde dimethyl acetal

1,1′-carbonyldiimidazole

DIPEA

benzyloxyamine hydrochloride

→

3-(4,4-dimethoxy-butyl)-1-(benzyloxy)-urea

Yield 74.1%

Solvents

THF

Conditions

Workup

1. 1
   ConcentrationThe mixture was concentrated under reduced pressure
2. 2
   workup.DISSOLUTIONthe residue was dissolved in DMF (50 mL)
3. 3
   Concentrationthen concentrated under reduced pressure
4. 4
   workup.DISSOLUTIONThe residue was dissolved in EtOAc (200 mL)
5. 5
   Washthe solution was washed with brine (5×25 mL)
6. 6
   Dryingdried (MgSO4)
7. 7
   Concentrationconcentrated
8. 8
   OtherPurification of the crude material by column chromatography on silica gel (4:1 hexanes-EtOAc followed by 100% EtOAc)

Procedure

To a solution of 4-aminobutyraldehyde dimethyl acetal (2.73 g, 20.5 mmol) in THF (50 mL) was added 1,1′-carbonyldiimidazole (3.39 g, 20.9 mmol) and the resultant mixture was stirred at room temperature for 45 minutes. The mixture was concentrated under reduced pressure and the residue was dissolved in DMF (50 mL) and treated with DIPEA (18 mL, 103 mmol) and benzyloxyamine hydrochloride (10.2 g, 64.0 mmol). The mixture was heated at 60° C. overnight then concentrated under reduced pressure. The residue was dissolved in EtOAc (200 mL) and the solution was washed with brine (5×25 mL), dried (MgSO4), and concentrated. Purification of the crude material by column chromatography on silica gel (4:1 hexanes-EtOAc followed by 100% EtOAc) provided 4.29 g (73%) of 3-(4,4-dimethoxy-butyl)-1-(benzyloxy)-urea as a yellow oil.

Source