Sodium Hydroxide → (S)-3-Boc-2,2-dimethyloxazolidine-4-propanoic Acid

Sodium hydroxide (27 mL of a 4.0 M solution in H2O, 108 mmol, 3.0 equiv.) was added to a solution of (4S)-4-(2-methoxycarbonylethyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester (prepared as described in Chida et al., J. Chem. Soc., Chem. Commun. 1992, 1064) (10.5 g, 36.5 mmol, 1 equiv.) in CH3OH (150 mL), and the resulting cloudy reaction mixture was stirred at 23° C. for 3.5 h. The mixture was concentrated under reduced pressure to 30 mL volume, and then was partitioned between 0.5 M HCl (150 mL) and EtOAc (2×150 mL). The combined organic layers were dried over MgSO4 and were gravity filtered. The filtrate was concentrated under reduced pressure and the residue dried under vacuum, to afford (4S)-4-(2′-carboxyethyl)-2,2-dimethyloxazolidine-3-carboxylic acid tert-butyl ester (10.0 g, 100% crude yield). This material was used without further purification: 1H NMR (CDCl3, mixture of rotamers) δ 1.49 (s), 1.57 (s), 1.60 (s), 1.84–2.05 (m), 2.39–2.41 (m), 3.71–3.74 (m), 3.91–4.05 (m).

1. customthe resulting cloudy reaction mixture
2. concentrationThe mixture was concentrated under reduced pressure to 30 mL volume
3. customwas partitioned between 0.5 M HCl (150 mL) and EtOAc (2×150 mL)
4. dry with materialThe combined organic layers were dried over MgSO4
5. filtrationfiltered
6. concentrationThe filtrate was concentrated under reduced pressure
7. customthe residue dried under vacuum

ORD record

ord-79a731aadb3d46ac80efcef08ac2b290

Source dataset

uspto-grants-2006_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06995142B2