Trifluoroacetic acid → (S)-5-(1,3-dioxoisoindolin-2-yl)-2-hydroxypentanoic acid

Participants

Reaction Steps

A solution of (S)-2-(tert-butoxycarbonylamino)-5-(1,3-dioxoisoindolin-2-yl)pentanoic acid L (1.45 g, 4.0 mmol) in dichloroethane (25 mL) was cooled to 0° C. Trifluoroacetic acid was added in one portion and the mixture was allowed to warm to room temperature and stir for 2 h. The mixture was concentrated to dryness mixed with water (18.5 mL), HOAc (9.5 mL) and aqueous NaNO2 (1.2 g in 25 mL H2O). After 15 min another portion of HOAc (14 mL) was added and the mixture was stirred at room temperature for 18 h. The reaction mixture was concentrated to dryness. The residue was dissolved in water (100 mL), the pH was adjusted to 1 by addition of 10% aqueous HCl, and the solution was extracted with diethyl ether (5×100 mL). The organic phase was dried over Na2SO4 and concentrated to dryness under reduced pressure afford (S)-5-(1,3-dioxoisoindolin-2-yl)-2-hydroxypentanoic acid LI (0.98 g, 3.73 mmol, 93%). ESIMS found for C13H13NO5 m/z 262 (M−H)−.

Provenance & Evidence