Methanol → methyl (S)-2-amino-4,4-difluoropentanoate hydrochloride

Temperatur

35 °C

At approx. 5° C. (ice bath cooling), 8.2 ml of thionyl chloride (112.6 mmol; 1.5 eq.) were added dropwise to 100 ml of methanol (p.a.) under argon. The mixture was allowed to come to RT within 30 min and stirred for a further 30 min. 19.0 g of (S)-2-tert-butoxycarbonylamino-4,4-difluoropentanoic acid (75.0 mmol) were added in portions to this reaction mixture. The reaction mixture was stirred at RT for 2 h. Thereafter, the reaction mixture was warmed to 35° C. (internal temperature) and stirred at this temperature for another 3 h. Subsequently, the mixture was concentrated under reduced pressure, which afforded methyl (S)-2-amino-4,4-difluoropentanoate hydrochloride as a slightly brownish crystalline solid which was clean enough for further reactions. Yield: 13.5 g (89% of theory).

1. stirringThe reaction mixture was stirred at RT for 2 h
2. stirringstirred at this temperature for another 3 h
3. concentrationSubsequently, the mixture was concentrated under reduced pressure, which

ORD-Eintrag

ord-81541a2355ef4a7d8269f2244caa8a81

Quelldatensatz

uspto-grants-2011_10

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08039480B2