Réaction #2175464

Équation de réaction

N-Boc-(L)-Dopa

tetrabutylammonium hydroxide

→

title compound 1a

Rendement 83.0%

(2S)-3-(3,4-Dihydroxyphenyl)-2-[(tert-butoxycarbonyl)amino]propanoic acid, tetrabutylammonium salt

Rendement 83.0%

Solvants

methanol

Conditions de réaction

Traitement

1. 1
   ConcentrationThe mixture was then concentrated under reduced pressure
2. 2
   Autredried
3. 3
   Autreby azeotroping twice with toluene
4. 4
   AutreThe residue was crystallized
5. 5
   LavageThe resulting crystalline solid was washed with acetone (400 mL×3)
6. 6
   Autrecollected on a Buchner funnel
7. 7
   Autredried under high vacuum

Mode opératoire

A solution of N-Boc-(L)-Dopa (175 g, 0.59 mol) in methanol (1 L) was cautiously mixed with a methanolic solution of tetrabutylammonium hydroxide (1.0 M, 0.55 L) at 0° C. for 30 min. The mixture was then concentrated under reduced pressure and dried by azeotroping twice with toluene. The residue was crystallized after cooling at 4° C. for 16 h. The resulting crystalline solid was washed with acetone (400 mL×3), collected on a Buchner funnel, and then dried under high vacuum to afford 245 g (83% yield) of the title compound 1a. 1H NMR (400 MHz, DMSO-d6): δ 0.94 (t, J=7.6 Hz, 12H), 1.30 (m, 17H), 1.60 (m, 8H), 3.18 (m, 8H), 4.58 (m, 1H), 5.68 (d, J=5.6 Hz, 1H), 6.30 (d, J=7.6 Hz, 1H), 6.46 (d, J=8.0 Hz, 1H), 6.51 (s, 1H), 8.85 (s, 1H): 8.94 (s, 1H).

Source