Reaction #7294

Reaction equation

cysteamine hydrochloride

ammonia

benzyl bromide

→

S-Benzylcysteamine

Yield 86.0%

Solvents

methanol

Conditions

Workup

1. 1
   Filtrationthe formed precipitate of S-dibenzylcysteamine was collected by filtration
2. 2
   ExtractionThe product was extracted with ether (3×100 mL)
3. 3
   Washthe organic phase was successively washed with brine (2×100 mL)
4. 4
   Dryingdried over MgSO4
5. 5
   Otherthe solvent evaporated in vacuo
6. 6
   OtherIt could, however be recrystallized from ethyl acetate

Procedure

To a suspension of 0.1 mole cysteamine hydrochloride in 20 mL methanol were added 13.6 mL of 25% ammonia solution, followed by dropwise addition of 0.12 mole benzyl bromide at room temperature. The mixture was stirred for 0.5 h, and the formed precipitate of S-dibenzylcysteamine was collected by filtration. The product was extracted with ether (3×100 mL) and the organic phase was successively washed with brine (2×100 mL), dried over MgSO4 and the solvent evaporated in vacuo. The crude product was essentially pure enough for the next step. It could, however be recrystallized from ethyl acetate. Yield 86%, of white solid. m.p. 85–6° C. NMR (CDCl3) in agreement with the title compound.

Source