(R)-b-AMino-3-fluorobenzenepropanol synthesis

Yield:774243-59-3 42%

Reaction Conditions:

Stage #1: (R)-2-amino-3-(3-fluorophenyl)propionic acidwith borane-THF in tetrahydrofuran at 0 - 25; for 5 h;
Stage #2: with sodium hydrogencarbonate in water; for 15 h;

Steps:

18.c Aminoalcohol 18c

To A THF solution (30 mL) of D-3-fluorophenylalanine (5 g, 27.3 mmol) at 0 C was added borane in THF (1 M, 68. 3 mL, 68. 3 mmol). After 5 h at 2 "C, to the solution was added sat'd NaHCO3 solution (10 mL), which was stirred for 15 h. The mixture was concentrated and extracted with methylene chloride (3X50 mL). Combined organic layers were dried (Na2SO4) and concentrated. The residue was purified by column chromatography (CH2Cl2/MeOH/NH4OH 95/5/0. 5 to 90/10/1) to give 1. 94 g (42% yield) of the compound 18c as a white solid. 1H NMR (CD3OD): δ 7.32-7.21 (1H, m), 7. 00-6. 98 (3H, m), 3. 63 (1H, dd, J=11. 1, 4. 2 Hz), 3. 38 (IH, dd, J=10. 5,6. 9 Hz), 3. 12 (1H, m), 2.79 (1H, dd, J=13. 5,5. 1 Hz), 2.54 (1H, dd, J=13. 5, 8. 4 Hz) ; LCMS (ESP) : 170 (M+H+).

References:

WO2004/87720,2004,A1 Location in patent:Page 62