Reaktion #2175467

Reaktionsgleichung

NaHCO3

hydrochloride salt

(2R)-2-Phenylcarbonyloxypropyl (2S)-2-amino-3-(3,4-dihydroxyphenyl)propanoate hydrochloride

Methanesulfonic acid

ethyl acetate

methanesulfonic acid

→

mesylate salt

Ausbeute 99.3%

(2R)-2-Phenylcarbonyloxypropyl (2S)-2-amino-3-(3,4-dihydroxyphenyl)propanoate mesylate

Ausbeute 99.3%

Lösungsmittel

water

water

Reaktionsbedingungen

Aufarbeitung

1. 1
   ExtraktionThe resulting aqueous suspension was extracted with ethyl acetate (EtOAc) (2×400 mL)
2. 2
   ExtraktionThe combined EtOAc extract
3. 3
   Waschenwas washed with water
4. 4
   Trocknenbrine, and dried through MgSO4
5. 5
   SonstigeWhite precipitate
6. 6
   Sonstigeformed as
7. 7
   workup.STIRRINGThe suspension was stirred for another 30 min
8. 8
   Filtrationfiltered
9. 9
   WaschenThe filter cake was washed three times with ethyl acetate (EtOAc) and vacuum
10. 10
    Sonstigedried overnight

Vorschrift

A solution of NaHCO3 (9.87 g, 117.5 mmol) in water (80 mL) was slowly added to a solution of hydrochloride salt 1d (31.0 g, 78.3 mmol) in water (300 mL). The resulting aqueous suspension was extracted with ethyl acetate (EtOAc) (2×400 mL). The combined EtOAc extract was washed with water, then brine, and dried through MgSO4. Methanesulfonic acid (6.04 mL, 93.12 mmol) was slowly added to the ethyl acetate (EtOAc) solution while stirred. White precipitate formed as soon as the addition of methanesulfonic acid was complete. The suspension was stirred for another 30 min and then filtered. The filter cake was washed three times with ethyl acetate (EtOAc) and vacuum dried overnight to afford 35.4 g (quantitative yield) of anhydrous mesylate salt 1 as a white solid. 1H NMR (400 MHz, CD3OD): δ 1.40 (d, J=6.4 Hz, 3H), 2.70 (s, 3H), 2.98 (dd, J=7.8, 14.6 Hz, 1H), 3.10 (dd, J=5.6, 14.4 Hz, 1H), 4.24 (dd, J=5.8, 7.8 Hz, 1H), 4.38 (dd, J=6.8, 12.0 Hz, 1H), 4.52 (dd, J=3.4, 11.8 Hz, 1H), 5.40 (dp, J=3.2, 6.4 Hz, 1H), 6.52 (dd, J=2.2, 8.2 Hz, 1H), 6.67 (d, J=2.2 Hz, 1H), 6.69 (d, J=8.0 Hz, 1H), 7.47 (t, J=7.6 Hz, 2H), 7.60 (br t, J=7.4 Hz, 1H), 8.01 (d, J=7.6 Hz, 2H). MS (ESI) m/z 360.07 (M+H)+ and 358.01 (M−H)−.

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