Réaction #7294

Équation de réaction

cysteamine hydrochloride

ammonia

benzyl bromide

→

S-Benzylcysteamine

Rendement 86.0%

Solvants

methanol

Conditions de réaction

Traitement

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
   Lavagethe organic phase was successively washed with brine (2×100 mL)
4. 4
   Séchagedried over MgSO4
5. 5
   Autrethe solvent evaporated in vacuo
6. 6
   AutreIt could, however be recrystallized from ethyl acetate

Mode opératoire

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