Triethylamine → Methyl L-prolinate

To a solution of L-proline methyl ester hydrochloride (257 mg, 1.43 mmol) in MeOH was added triethylamine (0.2 mL, 1.43 mmol). The solution was concentrated under reduced pressure to give a white solid residue, which was triturated with ether (3×). The collected ether solution was concentrated under reduced pressure to give L-proline methyl ester free amine (220 mg) as a colorless oil. To a solution of above free amine in toluene (5 mL) was added compound 1A (278 mg, 1.3 mmol), followed by 4 Å molecular sieves (1.0 g). The mixture was stirred at room temperature overnight and filtered. The filtrate was diluted with EtOAc, washed with 1 N aqueous HCl, water, brine, dried over MgSO4, concentrated under reduced pressure to give a crude product, which was chromatographed (silica gel) eluting with CH2Cl2, 0.5% MeOH in CH2Cl2 to give the title compound (410 mg, 92% yield) as a yellow foam.

1. concentrationThe solution was concentrated under reduced pressure
2. customto give a white solid residue, which
3. customwas triturated with ether (3×)
4. concentrationThe collected ether solution was concentrated under reduced pressure

ORD-Eintrag

ord-16d4886752374489ac6f02c5481ed97c

Quelldatensatz

uspto-grants-2003_12

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US06670386B2