Reaction #68557

Reaction equation

Water

1-(4-bromo-2-chlorophenyl)ethanone

ammonia

sodium borohydride

→

1-(4-bromo-2-chlorophenyl)ethanamine

Solvents

methanol

MeOH

Conditions

Workup

1. 1
   OtherReaction
2. 2
   OtherExothermic reaction
3. 3
   workup.STIRRINGstirred for an additional 10 min
4. 4
   OtherResulting white solid
5. 5
   Otherremoved via filtration through Celite
6. 6
   Filtrationfiltrated
7. 7
   ExtractionAqueous further extracted with 9:1 CHCl3/IPA (2×10 mL)
8. 8
   DryingCombined organics dried over MgSO4
9. 9
   Concentrationconcentrated
10. 10
    Otherpurified on silica (80 g)
11. 11
    Washeluting with 0>5% 2M NH3 in MeOH/DCM

Procedure

A solution of 1-(4-bromo-2-chlorophenyl)ethanone (2.430 g, 10 mmol), ammonia, 2.0 m solution in methanol (26 ml, 52 mmol) and titanium (iv) isopropoxide (6 ml, 21 mmol) was stirred for 16 h in a sealed vessel. Reaction then added to a freshly made suspension of sodium borohydride powder, 98% (4 g, 104 mmol) in MeOH (20 mL). Exothermic reaction started at 9:45 am, then continued to stir with a 45° C. external heating bath for 45 min. Water (10 mL) then added to reaction and stirred for an additional 10 min. Resulting white solid removed via filtration through Celite, and filtrated reduced in volume under reduced pressure. This suspension then partioned between 9:1 CHCl3/IPA (30 mL) and 1M NaOH (10 mL). Aqueous further extracted with 9:1 CHCl3/IPA (2×10 mL). Combined organics dried over MgSO4, concentrated, then purified on silica (80 g) eluting with 0>5% 2M NH3 in MeOH/DCM. MS (ESI pos. ion) m/z: 234/236 (MH+). Calc'd exact mass for C8H9BrClN: 233/235. 1-(4-bromo-2-chlorophenyl)ethanamine isolated as a colorless oil.

Source