Réaction #64923

Équation de réaction

HCl ether

22-2

2(S)-Phenylsulfonylamino-3-aminopropionic acid

H2SO4

isobutylene

→

22-3

tert-Butyl 2(S)-Phenylsulfonylamino-3-aminopropionate hydrochloride

Solvants

DME

CHCl3

Conditions de réaction

Traitement

1. 1
   AutreThe cooling bath removed
2. 2
   workup.ADDITIONice-water (250 mL) was added
3. 3
   Lavageby washing with ether (2×)
4. 4
   Extractionsaturated with NaCl, followed by extraction with EtOAc (3×)
5. 5
   LavageThe combined extracts were washed with brine
6. 6
   Séchagedried (MgSO4)
7. 7
   Concentrationconcentrated
8. 8
   Autreto give a white solid
9. 9
   Concentrationthen concentrated

Mode opératoire

In a Fischer-Porter tube, a mixture of 22-2 (102 g, 42 mmol) and DME (150 mL) was sequentially treated with H2SO4 (6.4 mL, 0.12 mol), cooled to -78° C., and then condensed isobutylene (75 mL). The cooling bath removed. After 2 h, ice-water (250 mL) was added followed by washing with ether (2×). The aqueous phase was basified with aq 5N NaOH, then saturated with NaCl, followed by extraction with EtOAc (3×). The combined extracts were washed with brine dried (MgSO4), and concentrated to give a white solid. This was dissolved in CHCl3 then treated with 1N HCl/ether (22 mL) then concentrated to give 22-3 as a glossy yellow solid.

Source